[Federal Register Volume 73, Number 95 (Thursday, May 15, 2008)]
[Rules and Regulations]
[Pages 28211-28303]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: E8-11105]



[[Page 28211]]

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Part II





Department of the Interior





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Fish and Wildlife Service



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50 CFR Part 17



Endangered and Threatened Wildlife and Plants; Determination of 
Threatened Status for the Polar Bear (Ursus maritimus) Throughout Its 
Range; Final Rule

Federal Register / Vol. 73 , No. 95 / Thursday, May 15, 2008 / Rules 
and Regulations

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DEPARTMENT OF THE INTERIOR

Fish and Wildlife Service

50 CFR Part 17

[FWS-R7-ES-2008-0038; 1111 FY07 MO-B2]
RIN 1018-AV19


Endangered and Threatened Wildlife and Plants; Determination of 
Threatened Status for the Polar Bear (Ursus maritimus) Throughout Its 
Range

AGENCY: Fish and Wildlife Service, Interior.

ACTION: Final rule.

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SUMMARY: We, the U.S. Fish and Wildlife Service (Service), determine 
threatened status for the polar bear (Ursus maritimus) under the 
Endangered Species Act of 1973, as amended (Act) (16 U.S.C. 1531 et 
seq.). Polar bears evolved to utilize the Arctic sea ice niche and are 
distributed throughout most ice-covered seas of the Northern 
Hemisphere. We find, based upon the best available scientific and 
commercial information, that polar bear habitat--principally sea ice--
is declining throughout the species' range, that this decline is 
expected to continue for the foreseeable future, and that this loss 
threatens the species throughout all of its range. Therefore, we find 
that the polar bear is likely to become an endangered species within 
the foreseeable future throughout all of its range. This final rule 
activates the consultation provisions of section 7 of the Act for the 
polar bear. The special rule for the polar bear, also published in 
today's edition of the Federal Register, sets out the prohibitions and 
exceptions that apply to this threatened species.

DATES: This rule is effective May 15, 2008. The U.S. District Court 
order in Center for Biological Diversity v. Kempthorne, No. C 08-1339 
CW (N.D. Cal., April 28, 2008) ordered that the 30-day notice period 
otherwise required by the Administrative Procedure Act be waived, 
pursuant to 5 U.S.C. 553(d)(3).

ADDRESSES: Comments and materials received, as well as supporting 
scientific documentation used in the preparation of this rule, will be 
available for public inspection, by appointment, during normal business 
hours at: U.S. Fish and Wildlife Service, Marine Mammals Management 
Office, 1011 East Tudor Road, Anchorage, AK 99503. Copies of this final 
rule are also available on the Service's Marine Mammal website: http://alaska.fws.gov/fisheries/mmm/polarbear/issues.htm.

FOR FURTHER INFORMATION CONTACT: Scott Schliebe, Marine Mammals 
Management Office (see ADDRESSES section) (telephone 907-786-3800). 
Persons who use a telecommunications device for the deaf (TDD) may call 
the Federal Information Relay Service (FIRS) at 1-800-877-8339, 24 
hours a day, 7 days a week.

SUPPLEMENTARY INFORMATION: 

Background

    Information in this section is summarized from the following 
sources: (1) The Polar Bear Status Review (Schliebe et al. 2006a); (2) 
information received from public comments in response to our proposal 
to list the polar bear as a threatened species published in the Federal 
Register on January 9, 2007 (72 FR 1064); (3) new information published 
since the proposed rule (72 FR 1064), including additional sea ice and 
climatological studies contained in the Intergovernmental Panel on 
Climate Change (IPCC) Fourth Assessment Report (AR4) and other 
published papers; and (4) scientific analyses conducted by the U.S. 
Geological Survey (USGS) and co-investigators at the request of the 
Secretary of the Department of the Interior specifically for this 
determination. For more detailed information on the biology of the 
polar bear, please consult the Status Review and additional references 
cited throughout this document.

Species Biology

Taxonomy and Evolution

    Throughout the Arctic, polar bears are known by a variety of common 
names, including nanook, nanuq, ice bear, sea bear, isbj[oslash]rn, 
white bears, and eisb[auml]r. Phipps (1774, p. 174) first proposed and 
described the polar bear as a species distinct from other bears and 
provided the scientific name Ursus maritimus. A number of alternative 
names followed, but Harington (1966, pp. 3-7), Manning (1971, p. 9), 
and Wilson (1976, p. 453) (all three references cited in Amstrup 2003, 
p. 587) subsequently promoted the name Ursus maritimus that has been 
used since.
    The polar bear is usually considered a marine mammal since its 
primary habitat is the sea ice (Amstrup 2003, p. 587), and it is 
evolutionarily adapted to life on sea ice (see further discussion under 
General Description section). The polar bear is included on the list of 
species covered under the U.S. Marine Mammal Protection Act of 1972, as 
amended (16 U.S.C. 1361 et seq.) (MMPA).
    Polar bears diverged from grizzly bears (Ursus arctos) somewhere 
between 200,000 and 400,000 years ago (Talbot and Shields 1996a, p. 
490; Talbot and Shields 1996b, p. 574). However, fossil evidence of 
polar bears does not appear until after the Last Interglacial Period 
(115,000 to 140,000 years ago) (Kurten 1964, p. 25; Ingolfsson and Wiig 
2007). Only in portions of northern Canada, Chukotka, Russia, and 
northern Alaska do the ranges of polar bears and grizzly bears overlap. 
Cross-breeding of grizzly bears and polar bears in captivity has 
produced reproductively viable offspring (Gray 1972, p. 56; Stirling 
1988, p. 23). The first documented case of cross-breeding in the wild 
was reported in the spring of 2006, and Wildlife Genetics International 
confirmed the cross-breeding of a female polar bear and male grizzly 
bear (Paetkau, pers. comm. May 2006).

General Description

    Polar bears are the largest of the living bear species (DeMaster 
and Stirling 1981, p. 1; Stirling and Derocher 1990, p. 190). They are 
characterized by large body size, a stocky form, and fur color that 
varies from white to yellow. They are sexually dimorphic; females weigh 
181 to 317 kilograms (kg) (400 to 700 pounds (lbs)), and males up to 
654 kg (1,440 lbs). Polar bears have a longer neck and a proportionally 
smaller head than other members of the bear family (Ursidae) and are 
missing the distinct shoulder hump common to grizzly bears. The nose, 
lips, and skin of polar bears are black (Demaster and Stirling 1981, p. 
1; Amstrup 2003, p. 588).
    Polar bears evolved in sea ice habitats and as a result are 
evolutionarily adapted to this habitat. Adaptations unique to polar 
bears in comparison to other Ursidae include: (1) White pelage with 
water-repellent guard hairs and dense underfur; (2) a short, furred 
snout; (3) small ears with reduced surface area; (4) teeth specialized 
for a carnivorous rather than an omnivorous diet; and (5) feet with 
tiny papillae on the underside, which increase traction on ice 
(Stirling 1988, p. 24). Additional adaptations include large, paddle-
like feet (Stirling 1988, p. 24), and claws that are shorter and more 
strongly curved than those of grizzly bears, and larger and heavier 
than those of black bears (Ursus americanus) (Amstrup 2003, p. 589).

Distribution and Movements

    Polar bears evolved to utilize the Arctic sea ice niche and are 
distributed throughout most ice-covered seas of the Northern 
Hemisphere. They occur throughout the East Siberian, Laptev, Kara, and 
Barents Seas of Russia; Fram Strait (the narrow strait between northern 
Greenland and Svalbard),

[[Page 28213]]

Greenland Sea and Barents Sea of northern Europe (Norway and Greenland 
(Denmark)); Baffin Bay, which separates Canada and Greenland, through 
most of the Canadian Arctic archipelago and the Canadian Beaufort Sea; 
and in the Chukchi and Beaufort Seas located west and north of Alaska.
    Over most of their range, polar bears remain on the sea ice year-
round or spend only short periods on land. However, some polar bear 
populations occur in seasonally ice-free environs and use land habitats 
for varying portions of the year. In the Chukchi Sea and Beaufort Sea 
areas of Alaska and northwestern Canada, for example, less than 10 
percent of the polar bear locations obtained via radio telemetry were 
on land (Amstrup 2000, p. 137; Amstrup, USGS, unpublished data); the 
majority of land locations were bears occupying maternal dens during 
the winter. A similar pattern was found in East Greenland (Wiig et al. 
2003, p. 511). In the absence of ice during the summer season, some 
populations of polar bears in eastern Canada and Hudson Bay remain on 
land for extended periods of time until ice again forms and provides a 
platform for them to move to sea. Similarly, in the Barents Sea, a 
portion of the population is spending greater amounts of time on land.
    Although polar bears are generally limited to areas where the sea 
is ice-covered for much of the year, they are not evenly distributed 
throughout their range on sea ice. They show a preference for certain 
sea ice characteristics, concentrations, and specific sea ice features 
(Stirling et al. 1993, pp. 18-22; Arthur et al. 1996, p. 223; Ferguson 
et al. 2000a, p. 1,125; Ferguson et al. 2000b, pp. 770-771; Mauritzen 
et al. 2001, p. 1,711; Durner et al. 2004, pp. 18-19; Durner et al. 
2006, p. pp. 34-35; Durner et al. 2007, pp. 17 and 19). Sea-ice habitat 
quality varies temporally as well as geographically (Ferguson et al. 
1997, p. 1,592; Ferguson et al. 1998, pp. 1,088-1,089; Ferguson et 
al.2000a, p. 1,124; Ferguson et al.2000b, pp. 770-771; Amstrup et al. 
2000b, p. 962). Polar bears show a preference for sea ice located over 
and near the continental shelf (Derocher et al. 2004, p. 164; Durner et 
al. 2004, p. 18-19; Durner et al. 2007, p. 19), likely due to higher 
biological productivity in these areas (Dunton et al. 2005, pp. 3,467-
3,468) and greater accessibility to prey in near-shore shear zones and 
polynyas (areas of open sea surrounded by ice) compared to deep-water 
regions in the central polar basin (Stirling 1997, pp. 12-14). Bears 
are most abundant near the shore in shallow-water areas, and also in 
other areas where currents and ocean upwelling increase marine 
productivity and serve to keep the ice cover from becoming too 
consolidated in winter (Stirling and Smith 1975, p. 132; Stirling et 
al. 1981, p. 49; Amstrup and DeMaster 1988, p. 44; Stirling 1990, pp. 
226-227; Stirling and [Oslash]ritsland 1995, p. 2,607; Amstrup et al. 
2000b, p. 960).
    Polar bear distribution in most areas varies seasonally with the 
seasonal extent of sea ice cover and availability of prey. The seasonal 
movement patterns of polar bears emphasize the role of sea ice in their 
life cycle. In Alaska in the winter, sea ice may extend 400 kilometers 
(km) (248 miles (mi)) south of the Bering Strait, and polar bears will 
extend their range to the southernmost proximity of the ice (Ray 1971, 
p. 13). Sea ice disappears from the Bering Sea and is greatly reduced 
in the Chukchi Sea in the summer, and polar bears occupying these areas 
move as much as 1,000 km (621 mi) to stay with the pack ice (Garner et 
al. 1990, p. 222; Garner et al. 1994, pp. 407-408). Throughout the 
polar basin during the summer, polar bears generally concentrate along 
the edge of or into the adjacent persistent pack ice. Significant 
northerly and southerly movements of polar bears appear to depend on 
seasonal melting and refreezing of ice (Amstrup 2000, p. 142). In other 
areas, for example, when the sea ice melts in Hudson Bay, James Bay, 
Davis Strait, Baffin Bay, and some portions of the Barents Sea, polar 
bears remain on land for up to 4 or 5 months while they wait for winter 
and new ice to form (Jonkel et al. 1976, pp. 13-22; Schweinsburg 1979, 
pp. 165, 167; Prevett and Kolenosky 1982, pp. 934-935; Schweinsburg and 
Lee 1982, p. 510; Ferguson et al. 1997, p. 1,592; Lunn et al. 1997, p. 
235; Mauritzen et al. 2001, p. 1,710).
    In areas where sea ice cover and character are seasonally dynamic, 
a large multi-year home range, of which only a portion may be used in 
any one season or year, is an important part of the polar bear life 
history strategy. In other regions, where ice is less dynamic, home 
ranges are smaller and less variable (Ferguson et al. 2001, pp.51-52). 
Data from telemetry studies of adult female polar bears show that they 
do not wander aimlessly on the ice, nor are they carried passively with 
the ocean currents as previously thought (Pedersen 1945 cited in 
Amstrup 2003, p. 587). Results show strong fidelity to activity areas 
that are used over multiple years (Ferguson et al. 1997, p. 1,589). All 
areas within an activity area are not used each year.
    The distribution patterns of some polar bear populations during the 
open water and early fall seasons have changed in recent years. In the 
Beaufort Sea, for example, greater numbers of polar bears are being 
found on shore than recorded at any previous time (Schliebe et al. 
2006b, p. 559). In Baffin Bay, Davis Strait, western Hudson Bay and 
other areas of Canada, Inuit hunters are reporting an increase in the 
numbers of bears present on land during summer and fall (Dowsley and 
Taylor 2005, p. 2; Dowsley 2005, p. 2). The exact reasons for these 
changes may involve a number of factors, including changes in sea ice 
(Stirling and Parkinson 2006, p. 272).

Food Habits

    Polar bears are carnivorous, and a top predator of the Arctic 
marine ecosystem. Polar bears prey heavily throughout their range on 
ice-dependent seals (frequently referred to as ``ice seals''), 
principally ringed seals (Phoca hispida), and, to a lesser extent, 
bearded seals (Erignathus barbatus). In some locales, other seal 
species are taken. On average, an adult polar bear needs approximately 
2 kg (4.4 lbs) of seal fat per day to survive (Best 1985, p. 1035). 
Sufficient nutrition is critical and may be obtained and stored as fat 
when prey is abundant.
    Although seals are their primary prey, polar bears occasionally 
take much larger animals such as walruses (Odobenus rosmarus), narwhal 
(Monodon monoceros), and belugas (Delphinapterus leucas) (Kiliaan and 
Stirling 1978, p. 199; Smith 1980, p. 2,206; Smith 1985, pp. 72-73; 
Lowry et al. 1987, p. 141; Calvert and Stirling 1990, p. 352; Smith and 
Sjare 1990, p. 99). In some areas and under some conditions, prey other 
than seals or carrion may be quite important to polar bear sustenance 
as short-term supplemental forms of nutrition. Stirling and 
[Oslash]ritsland (1995, p. 2,609) suggested that in areas where ringed 
seal populations were reduced, other prey species were being 
substituted. Like other ursids, polar bears will eat human garbage 
(Lunn and Stirling 1985, p. 2,295), and when confined to land for long 
periods, they will consume coastal marine and terrestrial plants and 
other terrestrial foods (Russell 1975, p. 122; Derocher et al. 1993, p. 
252); however the significance of such other terrestrial foods to the 
long-term welfare of polar bears may be limited (Lunn and Stirling 
1985, p. 2,296; Ramsay and Hobson 1991, p. 600; Derocher et al. 2004, 
p. 169) as further expanded under the section entitled ``Adaptation'' 
below.

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Reproduction

    Polar bears are characterized by late sexual maturity, small litter 
sizes, and extended parental investment in raising young, all factors 
that contribute to a low reproductive rate (Amstrup 2003, pp. 599-600). 
Reproduction in the female polar bear is similar to that in other 
ursids. Females generally mature and breed for the first time at 4 or 5 
years and give birth at 5 or 6 years of age. Litters of two cubs are 
most common, but litters of three cubs are seen sporadically across the 
Arctic (Amstrup 2003, p. 599). When foraging conditions are difficult, 
polar bears may ``defer'' reproduction in favor of survival (Derocher 
et al. 1992, p. 564).
    Polar bears enter a prolonged estrus between March and June, when 
breeding occurs. Ovulation is induced by mating (Wimsatt 1963, p. 72), 
and implantation is delayed until autumn. The total gestation period is 
195 to 265 days (Uspenski 1977, cited in Amstrup 2003, p. 599), 
although active development of the fetus is suspended during most of 
this period. The timing of implantation, and therefore the timing of 
birth, is likely dependent on body condition of the female, which 
depends on a variety of environmental factors. Pregnant females that 
spend the late summer on land prior to denning may not feed for 8 
months (Watts and Hansen 1987, p. 627). This may be the longest period 
of food deprivation of any mammal, and it occurs at a time when the 
female gives birth to and then nourishes new cubs.
    Newborn polar bears are helpless and have hair, but are blind and 
weigh only 0.6 kg (1.3 lb) (Blix and Lentfer 1979, p. 68). Cubs grow 
rapidly, and may weigh 10 to 12 kg (22 to 26 lbs) by the time they 
emerge from the den in the spring. Young bears will stay with their 
mothers until weaning, which occurs most commonly in early spring when 
the cubs are 2.3 years of age. Female polar bears are available to 
breed again after their cubs are weaned; thus the reproductive interval 
for polar bears is 3 years.
    Polar bears are long-lived mammals not generally susceptible to 
disease, parasites, or injury. The oldest known female in the wild was 
32 years of age and the oldest known male was 28, though few polar 
bears in the wild live to be older than 20 years (Stirling 1988, p. 
139; Stirling 1990, p. 225). Due to extremely low reproductive rates, 
polar bears require a high survival rate to maintain population levels 
(Eberhardt 1985, p. 1,010; Amstrup and Durner 1995, pp. 1,313, 1,319). 
Survival rates increase up to a certain age, with cubs-of-the-year 
having the lowest rates and prime age adults (between 5 and 20 years of 
age) having survival rates that can exceed 90 percent. Amstrup and 
Durner (1995, p. 1,319) report that high survival rates (exceeding 90 
percent for adult females) are essential to sustain populations.

Polar Bear--Sea Ice Habitat Relationships

    Polar bears are distributed throughout the ice-covered waters of 
the circumpolar Arctic (Stirling 1988, p. 61), and rely on sea ice as 
their primary habitat (Amstrup 2003, p. 587). Polar bears depend on sea 
ice for a number of purposes, including as a platform from which to 
hunt and feed upon seals; as habitat on which to seek mates and breed; 
as a platform to move to terrestrial maternity denning areas, and 
sometimes for maternity denning; and as a substrate on which to make 
long-distance movements (Stirling and Derocher 1993, p. 241). Mauritzen 
et al. (2003b, p. 123) indicated that habitat use by polar bears during 
certain seasons may involve a trade-off between selecting habitats with 
abundant prey availability versus the use of safer retreat habitats 
(i.e., habitats where polar bears have lower probability of becoming 
separated from the main body of the pack ice) of higher ice 
concentrations with less prey. Their findings indicate that polar bear 
distribution may not be solely a reflection of prey availability, but 
other factors such as energetic costs or risk may be involved.
    Stirling et al. (1993, p. 15) defined seven types of sea ice 
habitat and classified polar bear use of these ice types based on the 
presence of bears or bear tracks in order to determine habitat 
preferences. The seven types of sea ice are: (1) stable fast ice with 
drifts; (2) stable fast ice without drifts; (3) floe edge ice; (4) 
moving ice; (5) continuous stable pressure ridges; (6) coastal low 
level pressure ridges; and (7) fiords and bays. Polar bears were not 
evenly distributed over these sea ice habitats, but concentrated on the 
floe ice edge, on stable fast ice with drifts, and on areas of moving 
ice (Stirling 1990 p. 226; Stirling et al. 1993, p. 18). In another 
assessment, categories of ice types included pack ice, shore-fast ice, 
transition zone ice, polynyas, and leads (linear openings or cracks in 
the ice) (USFWS 1995, p. 9). Pack ice, which consists of annual and 
multi-year older ice in constant motion due to winds and currents, is 
the primary summer habitat for polar bears in Alaska. Shore-fast ice 
(also known as ``fast ice'', it is defined by the Arctic Climate Impact 
Assessment (2005, p. 190) as ice that grows seaward from a coast and 
remains in place throughout the winter; typically it is stabilized by 
grounded pressure ridges at its outer edge) is used for feeding on seal 
pups, for movement, and occasionally for maternity denning. Open water 
at leads and polynyas attracts seals and other marine mammals and 
provides preferred hunting habitats during winter and spring. Durner et 
al. (2004, pp. 18-19; Durner et al. 2007, pp. 17-18) found that polar 
bears in the Arctic basin prefer sea ice concentrations greater than 50 
percent located over the continental shelf with water depths less than 
300 m (984 feet (ft)).
    Polar bears must move throughout the year to adjust to the changing 
distribution of sea ice and seals (Stirling 1988, p. 63; USFWS 1995, p. 
4). In some areas, such as Hudson Bay and James Bay, polar bears remain 
on land when the sea ice retreats in the spring and they fast for 
several months (up to 8 months for pregnant females) before fall 
freeze-up (Stirling 1988, p. 63; Derocher et al. 2004, p. 163; Amstrup 
et al. 2007, p. 4). Some populations unconstrained by land masses, such 
as those in the Barents, Chukchi, and Beaufort Seas, spend each summer 
on the multi-year ice of the polar basin (Derocher et al. 2004, p. 163; 
Amstrup et al. 2007, p. 4). In intermediate areas such as the Canadian 
Arctic, Svalbard, and Franz Josef Land archipelagos, bears stay on the 
sea ice most of the time, but in some years they may spend up to a few 
months on land (Mauritizen et al. 2001, p. 1,710). Most populations use 
terrestrial habitat partially or exclusively for maternity denning; 
therefore, females must adjust their movements in order to access land 
at the appropriate time (Stirling 1988, p. 64; Derocher et al. 2004, p. 
166).
    Sea ice changes between years in response to environmental factors 
may have consequences for the distribution and productivity of polar 
bears as well as their prey. In the southern Beaufort Sea, anomalous 
heavy sea ice conditions in the mid-1970s and mid-1980s (thought to be 
roughly in phase with a similar variation in runoff from the Mackenzie 
River) caused significant declines in productivity of ringed seals 
(Stirling 2002, p. 68). Each event lasted approximately 3 years and 
caused similar declines in the birth rate of polar bears and survival 
of subadults, after which reproductive success and survival of both 
species increased again.

Maternal Denning Habitat

    Throughout the species' range, most pregnant female polar bears 
excavate

[[Page 28215]]

dens in snow located on land in the fall-early winter period (Harington 
1968, p. 6; Lentfer and Hensel 1980, p. 102; Ramsay and Stirling 1990, 
p. 233; Amstrup and Gardner 1994, p. 5). The only known exceptions are 
in western and southern Hudson Bay, where polar bears first excavate 
earthen dens and later reposition into adjacent snow drifts (Jonkel et 
al. 1972, p. 146; Ramsay and Stirling 1990, p. 233), and in the 
southern Beaufort Sea, where a portion of the population dens in snow 
caves located on pack and shore-fast ice. Successful denning by polar 
bears requires accumulation of sufficient snow for den construction and 
maintenance. Adequate and timely snowfall combined with winds that 
cause snow accumulation leeward of topographic features create denning 
habitat (Harington 1968, p. 12).
    A great amount of polar bear denning occurs in core areas 
(Harington 1968, pp. 7-8), which show high use over time (see Figure 
8). In some portions of the species' range, polar bears den in a more 
diffuse pattern, with dens scattered over larger areas at lower density 
(Lentfer and Hensel 1980, p. 102; Stirling and Andriashek 1992, p. 363; 
Amstrup 1993, p. 247; Amstrup and Gardner 1994, p. 5; Messier et al. 
1994, p. 425; Born 1995, p. 81; Ferguson et al. 2000a, p. 1125; Durner 
et al. 2001, p. 117; Durner et al. 2003, p. 57).
    Habitat characteristics of denning areas vary substantially from 
the rugged mountains and fjordlands of the Svalbard archipelago and the 
large islands north of the Russian coast (L[oslash]n[oslash] 1970, p. 
77; Uspenski and Kistchinski 1972, p. 182; Larsen 1985, pp. 321-322), 
to the relatively flat topography of areas such as the west coast of 
Hudson Bay (Ramsay and Andriashek 1986, p. 9; Ramsay and Stirling 1990, 
p. 233) and north slope of Alaska (Amstrup 1993, p. 247; Amstrup and 
Gardner 1994, p. 7; Durner et al. 2001, p. 119; Durner et al. 2003, p. 
61), to offshore pack ice-pressure ridge habitat (Amstrup and Gardner 
1994, p. 4; Fischbach et al. 2007, p. 1,400). The key characteristic of 
all denning habitat is topographic features that catch snow in the 
autumn and early winter (Durner et al. 2003, p. 61). Across the range, 
most polar bear dens occur relatively near the coast. The main 
exception to coastal denning occurs in the western Hudson Bay area, 
where bears den farther inland in traditional denning areas (Kolenosky 
and Prevett 1983, pp. 243-244; Stirling and Ramsay 1986, p. 349).

Current Population Status and Trend

    The total number of polar bears worldwide is estimated to be 
20,000-25,000 (Aars et al. 2006, p. 33). Polar bears are not evenly 
distributed throughout the Arctic, nor do they comprise a single 
nomadic cosmopolitan population, but rather occur in 19 relatively 
discrete populations (Aars et al. 2006, p. 33). The use of the term 
``relatively discrete population'' in this context is not intended to 
equate to the Act's term ``distinct population segments'' (Figure 1). 
Boundaries of the 19 polar bear populations have evolved over time and 
are based on intensive study of movement patterns, tag returns from 
harvested animals, and, to a lesser degree, genetic analysis (Aars et 
al. 2006, pp. 33-47). The scientific studies regarding population 
bounds began in the early 1970s and continue today. Within this final 
rule we have adopted the use of the term ``population'' to describe 
polar bear management units consistent with their designation by the 
World Conservation Union-International Union for Conservation of Nature 
and Natural Resources (IUCN), Species Survival Commission (SSC) Polar 
Bear Specialist Group (PBSG) with information available as of October 
2006 (Aars et al. 2006, p. 33), and to describe a combination of two or 
more of these populations into ``ecoregions,'' as discussed in 
following sections. Although movements of individual polar bears 
overlap extensively, telemetry studies demonstrate spatial segregation 
among groups or stocks of polar bears in different regions of their 
circumpolar range (Schweinsburg and Lee 1982, p. 509; Amstrup et al. 
1986, p. 252; Amstrup et al., 2000b, pp. 957-958.; Garner et al. 1990, 
p. 224; Garner et al. 1994, pp.112-115; Amstrup and Gardner 1994, p. 7; 
Ferguson et al. 1999, pp. 313-314; Lunn et al. 2002, p. 41). These 
patterns, along with information obtained from survey and 
reconnaissance, marking and tagging studies, and traditional knowledge, 
have resulted in recognition of 19 relatively discrete polar bear 
populations (Aars et al. 2006, p. 33). Genetic analysis reinforces the 
boundaries between some designated populations (Paetkau et al. 1999, p. 
1,571; Amstrup 2003, p. 590) while confirming the existence of overlap 
and mixing among others (Paetkau et al. 1999, p. 1,571; Cronin et al. 
2006, p. 655). There is considerable overlap in areas occupied by 
members of these groups (Amstrup et al. 2004, p. 676; Amstrup et al. 
2005, p. 252), and boundaries separating the groups are adjusted as new 
data are collected. These boundaries, however, are thought to be 
ecologically meaningful, and the 19 units they describe are managed as 
populations, with the exception of the Arctic Basin population where 
few bears are believed to be year-round residents.

[[Page 28216]]

[GRAPHIC] [TIFF OMITTED] TR15MY08.002

    Population size estimates and qualitative categories of current 
trend and status for each of the 19 polar bear populations are 
discussed below. This discussion was derived from information presented 
at the IUCN/SSC PBSG meeting held in Seattle, Washington, in June 2005, 
and updated with results that became available in October 2006 (Aars et 
al. 2006, p. 33). The following narrative incorporates results from two 
recent publications (Stirling et al. 2007; Obbard et al. 2007). The 
remainder of the information on each population is based on the 
available status reports and revisions given by each nation, as 
reported in Aars et al. (2006).
    Status categories include an assessment of whether a population is 
believed to be not reduced, reduced, or severely reduced from historic 
levels of abundance, or if insufficient data are available to estimate 
status. Trend categories include an assessment of whether the 
population is currently increasing, stable, or declining, or if 
insufficient data are available to estimate trend. In general, an 
assessment of trend requires a monitoring program or data to allow 
population size to be estimated at more than one point in time. 
Information on the date of the current population estimate and 
information on previous population estimates and the basis for

[[Page 28217]]

those estimates is detailed in Aars et al. (2006, pp. 34-35). In some 
instances a subjective assessment of trend has been provided in the 
absence of either a monitoring program or estimates of population size 
developed for more than one point in time. This status and trend 
analysis only reflects information about the past and present polar 
bear populations. Later in this final rule a discussion will be 
presented about the scientific information on threats that will affect 
the species within the foreseeable future. The Act establishes a five-
factor analysis for using this information in making listing decisions.
    Populations are discussed in a counterclockwise order from Figure 
1, beginning with East Greenland. There is no population size estimate 
for the East Greenland polar bear population because no population 
surveys have been conducted there. Thus, the status and trend of this 
population have not been determined. The Barents Sea population was 
estimated to comprise 3,000 animals based on the only population survey 
conducted in 2004. Because only one abundance estimate is available, 
the status and trend of this population cannot yet be determined. There 
is no population size estimate for the Kara Sea population because 
population surveys have not been conducted; thus status and trend of 
this population cannot yet be determined. The Laptev Sea population was 
estimated to comprise 800 to 1,200 animals, on the basis of an 
extrapolation of historical aerial den survey data (1993). Status and 
trend cannot yet be determined for this population.
    The Chukchi Sea population is estimated to comprise 2,000 animals, 
based on extrapolation of aerial den surveys (2002). Status and trend 
cannot yet be determined for this population. The Southern Beaufort Sea 
population is comprised of 1,500 animals, based on a recent population 
inventory (2006). The predicted trend is declining (Aars et al. 2006, 
p.33), and the status is designated as reduced. The Northern Beaufort 
Sea population was estimated to number 1,200 animals (1986). The trend 
is designated as stable, and status is believed to be not reduced. 
Stirling et al. (2007, pp. 12-14) estimated long-term trends in 
population size for the Northern Beaufort Sea population. The model-
averaged estimate of population size from 2004 to 2006 was 980 bears, 
and did not differ in a statistically significantly way from estimates 
for the periods of 1972 to 1975 (745 bears) and 1985 to 1987 (867 
bears), and thus the trend is stable. Stirling et al. (2007, p. 13) 
indicated that, based on a number of indications and separate annual 
abundance estimates for the study period, the population estimate may 
be slightly biased low (i.e., might be an underestimate) due to 
sampling issues.
    The Viscount Melville Sound population was estimated to number 215 
animals (1992). The observed or predicted trend based on management 
action is listed as increasing (Aars et al. 2006, p. 33), although the 
status is designated as severely reduced from prior excessive harvest. 
The Norwegian Bay population estimate was 190 animals (1998); the 
trend, based on computer simulations, is noted as declining, while the 
status is listed as not reduced. The Lancaster Sound population 
estimate was 2,541 animals (1998); the trend is thought to be stable, 
and status is not reduced. The M'Clintock Channel population is 
estimated at 284 animals (2000); the observed or predicted trend based 
on management actions is listed as increasing although the status is 
severely reduced from excessive harvest. The Gulf of Boothia population 
estimate is 1,523 animals (2000); the trend is thought to be stable, 
and status is designated as not reduced. The Foxe Basin population was 
estimated to number 2,197 animals in 1994; the population trend is 
thought to be stable, and the status is not reduced. The Western Hudson 
Bay population estimate is 935 animals (2004); the trend is declining, 
and the status is reduced. The Southern Hudson Bay population was 
estimated to be 1,000 animals in 1988 (Aars et al. 2006, p. 35); the 
trend is thought to be stable, and status is not reduced. In a more 
recent analysis, Obbard et al. (2007) applied open population capture-
recapture models to data collected from 1984-86 and 1999-2005 to 
estimate population size, trend, and survival for the Southern Hudson 
Bay population. Their results indicate that the size of the Southern 
Hudson Bay population appears to be unchanged from the mid-1980s. From 
1984-1986, the population was estimated at 641 bears; from 2003-2005, 
the population was estimated at 681 bears. Thus, the trend for this 
population is stable. The Kane Basin population was estimated to be 
comprised of 164 animals (1998); its trend is declining, and status is 
reduced. The Baffin Bay population was estimated to be 2,074 animals 
(1998); the trend is declining, and status is reduced. The Davis Strait 
population was estimated to number 1,650 animals based on traditional 
ecological knowledge (TEK) (2004); data were unavailable to assess 
trends or status. Preliminary information from the second of a 3-year 
population assessment estimates the population number to be 2,375 bears 
(Peacock et al. 2007, p. 7). The Arctic Basin population estimate, 
trend, and status are unknown (Aars et al. 2006, p. 35).
    On the basis of information presented above, two polar bear 
populations are designated as increasing (Viscount Melville Sound and 
M'Clintock Channel-both were severely reduced in the past and are 
recovering under conservative harvest limits); six populations are 
stable (Northern Beaufort Sea, Southern Hudson Bay, Davis Strait, 
Lancaster Sound, Gulf of Bothia, Foxe Basin); five populations are 
declining (Southern Beaufort Sea, Norwegian Bay, Western Hudson Bay, 
Kane Basin, Baffin Bay); and six populations are designated as data 
deficient (Barents Sea, Kara Sea, Laptev Sea, Chukchi Sea, Arctic 
Basin, East Greenland) with no estimate of trend. The two populations 
with the most extensive time series of data, Western Hudson Bay and 
Southern Beaufort Sea, are both considered to be declining.
    As previously noted, scientific information assessing this species 
in the foreseeable future is provided later in this final rule.

Polar Bear Ecoregions

    Amstrup et al. (2007, pp. 6-8) grouped the 19 IUCN-recognized polar 
bear populations (Aars et al. 2006, p. 33) into four physiographically 
different functional groups or ``ecoregions'' (Figure 2) in order to 
forecast future polar bear population status on the basis of current 
knowledge of polar bear populations, their relationships to sea ice 
habitat, and predicted changes in sea ice and other environmental 
variables. Amstrup et al. (2007, p. 7) defined the ecoregions ``on the 
basis of observed temporal and spatial patterns of ice formation and 
ablation (melting or evaporation), observations of how polar bears 
respond to those patterns, and how general circulation models (GCMs) 
forecast future ice patterns.''
    The Seasonal Ice Ecoregion includes the Western and Southern Hudson 
Bay populations, as well as the Foxe Basin, Baffin Bay, and Davis 
Strait populations. These 5 IUCN-recognized populations are thought to 
include a total of about 7,200 polar bears (Aars et al. 2006, p. 34-
35). The 5 populations experience sea ice that melts entirely in 
summer, and bears spend extended periods of time on shore.

[[Page 28218]]

[GRAPHIC] [TIFF OMITTED] TR15MY08.003

    The Archipelago Ecoregion, islands and channels of the Canadian 
Arctic, has approximately 5,000 polar bears representing 6 populations 
recognized by the IUCN (Aars et al. 2006, p. 34-35). These populations 
are Kane Basin, Norwegian Bay, Viscount Melville Sound, Lancaster 
Sound, M'Clintock Channel, and the Gulf of Boothia. Much of this region 
is characterized by heavy annual and multi-year ice that fills the 
inter-island channels year round and polar bears remain on the sea ice 
throughout the year.
    The polar basin was split into a Convergent Ecoregion and a 
Divergent Ecoregion, based upon the different patterns of sea ice 
formation, loss (via melt and transport) (Rigor et al. 2002, p. 2,658; 
Rigor and Wallace 2004, p. 4; Maslanik et al. 2007, pp. 1-3; Meier et 
al. 2007, pp. 428-434; Ogi and Wallace 2007, pp. 2-3).
    The Divergent Ecoregion is characterized by extensive formation of 
annual sea ice that is transported toward the Canadian Arctic islands 
and Greenland, or out of the polar basin through Fram Strait. The 
Divergent ecoregion includes the Southern Beaufort, Chukchi, Laptev, 
Kara, and Barents Seas populations, and is thought to contain up to 
9,500 polar bears. In the Divergent Ecoregion, as in the Archipelago 
Ecoregion, polar bears mainly stay on the sea ice year-round.
    The Convergent Ecoregion, composed of the Northern Beaufort Sea, 
Queen Elizabeth Islands (see below), and East Greenland populations, is 
thought to contain approximately 2,200 polar bears. Amstrup et al. 
(2007, p. 7) modified the IUCN-recognized population boundaries (Aars 
et al. 2006, pp. 33,36) of this ecoregion by redefining a Queen 
Elizabeth Islands population and extending the original boundary of 
that population to include northwestern Greenland (see Figure 2). The 
area contained within this boundary is characterized by heavy multi-
year ice, except for a recurring lead system that runs along the Queen 
Elizabeth Islands from the northeastern Beaufort Sea to northern 
Greenland (Stirling 1980, pp. 307-308). The area may contain over 200 
polar bears and some bears from other regions have been recorded moving 
through the area (Durner and Amstrup 1995, p. 339; Lunn et al. 1995, 
pp. 12-13). The Northern Beaufort Sea and Queen Elizabeth Islands 
populations occur in a region of the polar basin that accumulates ice 
(hence, the Convergent Ecoregion) as it is moved from the polar basin 
Divergent Ecoregion, while the East Greenland population occurs in area 
where ice is transported out of the polar basin through the Fram Strait 
(Comiso 2002, pp. 17-18; Rigor and Wallace 2004, p. 3; Belchansky et 
al. 2005, pp. 1-2; Holland et al. 2006, pp. 1-5; Durner et al. 2007, p. 
3; Ogi and Wallace 2007, p. 2; Serreze et al. 2007, pp. 1,533-1536).
    Amstrup et al. (2007) do not incorporate the central Arctic Basin 
population into an ecoregion. This population was defined by the IUCN 
in 2001 (Lunn et al. 2002, p.29) to recognize polar bears that may 
reside outside the territorial jurisdictions of the polar nations. The 
Arctic Basin region is characterized by very deep water, which is known 
to be unproductive (Pomeroy 1997, pp. 6-7). Available data indicate 
that polar bears prefer sea ice over shallow water (less then 300 m 
(984 ft) deep) (Amstrup et

[[Page 28219]]

al. 2000b, p. 962; Amstrup et al. 2004, p. 675; Durner et al. 2007, pp. 
18-19), and it is thought that this preference reflects increased 
hunting opportunities over more productive waters. Also, tracking 
studies indicate that few if any bears are year-round residents of the 
central Arctic Basin, and therefore this relatively unpopulated portion 
of the Arctic was not designated as an ecoregion.

Sea Ice Environment

    As described in detail in the ``Species Biology'' section of this 
rule, above, polar bears are evolutionarily adapted to life on sea ice 
(Stirling 1988, p. 24; Amstrup 2003, p. 587). They need sea ice as a 
platform for hunting, for seasonal movements, for travel to terrestrial 
denning areas, for resting, and for mating (Stirling and Derocher 1993, 
p. 241). Moore and Huntington (in press) classify the polar bear as an 
``ice-obligate'' species because of its reliance on sea ice as a 
platform for resting, breeding, and hunting, while Laidre et al. (in 
press) similarly describe the polar bear as a species that principally 
relies on annual sea ice over the continental shelf and areas toward 
the southern edge of sea ice for foraging. Some polar bears use 
terrestrial habitats seasonally (e.g., for denning or for resting 
during open water periods). Open water is not considered to be an 
essential habitat type for polar bears, because life functions such as 
feeding, reproduction, or resting do not occur in open water. However, 
open water is a fundamental part of the marine system that supports 
seal species, the principal prey of polar bears, and seasonally 
refreezes to form the ice needed by the bears (see ``Open Water 
Habitat'' section for more information). Further, the open water 
interface with sea ice is an important habitat used to a great extent 
by polar bears. In addition, the extent of open water is important 
because vast areas of open water may limit a bear's ability to access 
sea ice or land (see ``Open Water Swimming'' section for more detail). 
Snow cover, both on land and on sea ice, is an important component of 
polar bear habitat in that it provides insulation and cover for young 
polar bears and ringed seals in snow dens or lairs (see ``Maternal 
Denning Habitat'' section for more detail).

Sea Ice Habitat

Overview of Arctic Sea Ice

    According to the Arctic Climate Impact Assessment (ACIA 2005), 
approximately two-thirds of the Arctic is ocean, including the Arctic 
Ocean and its shelf seas plus the Nordic, Labrador, and Bering Seas 
(ACIA 2005, p. 454). Sea ice is the defining characteristic of the 
marine Arctic (ACIA 2005, p. 30). The Arctic sea ice environment is 
highly dynamic and follows annual patterns of expansion and 
contraction. Sea ice is typically at its maximum extent (the term 
``extent'' is formally defined in the ``Observed Changes in Arctic Sea 
Ice'' section) in March and at its minimum extent in September 
(Parkinson et al. 1999, p. 20,840). The two primary forms of sea ice 
are seasonal (or first year) ice and perennial (or multi-year) ice 
(ACIA 2005, p. 30). Seasonal ice is in its first autumn/winter of 
growth or first spring/summer of melt (ACIA 2005, p. 30). It has been 
documented to vary in thickness from a few tenths of a meter near the 
southern margin of the sea ice to 2.5 m (8.2 ft) in the high Arctic at 
the end of winter (ACIA 2005, p. 30), with some ice also that is 
thinner and some limited amount of ice that can be much thicker, 
especially in areas with ridging (C. Parkinson, NASA, in litt. to the 
Service, November 2007). If first-year ice survives the summer melt, it 
becomes multi-year ice. This ice tends to develop a distinctive 
hummocky appearance through thermal weathering, becoming harder and 
almost salt-free over several years (ACIA 2005, p. 30). Sea ice near 
the shore thickens in shallow waters during the winter, and portions 
become grounded. Such ice is known as shore-fast ice, land-fast ice, or 
simply fast ice (ACIA 2005, p. 30). Fast ice is found along much of the 
Siberian coast, the White Sea (an inlet of the Barents Sea), north of 
Greenland, the Canadian Archipelago, Hudson Bay, and north of Alaska 
(ACIA 2005, p. 457).
    Pack ice consists of seasonal (or first-year) and multi-year ice 
that is in constant motion caused by winds and currents (USFWS 1995, 
pp. 7-9). Pack ice is used by polar bears for traveling, feeding, and 
denning, and it is the primary summer habitat for polar bears, 
including the Southern Beaufort Sea and Chukchi Sea populations, as 
first year ice retreats and melts with the onset of spring (see ``Polar 
Bear-Sea Ice Habitat Relationships'' section for more detail on ice 
types used by polar bears). Movements of sea ice are related to winds, 
currents, and seasonal temperature fluctuations that in turn promote 
its formation and degradation. Ice flow in the Arctic often includes a 
clockwise circulation of sea ice within the Canada Basin and a 
transpolar drift stream that carries sea ice from the Siberian shelves 
to the Barents Sea and Fram Strait.
    Sea ice is an important component of the Arctic climate system 
(ACIA 2005, p. 456). It is an effective insulator between the oceans 
and the atmosphere. It also strongly reduces the ocean-atmosphere heat 
exchange and reduces wind stirring of the ocean. In contrast to the 
dark ocean, pond-free sea ice (i.e., sea ice that has no meltwater 
ponds on the surface) reflects most of the solar radiation back into 
space. Together with snow cover, sea ice greatly restricts the 
penetration of light into the sea, and it also provides a surface for 
particle and snow deposition (ACIA 2005, p. 456). Its effects can 
extend far south of the Arctic, perhaps globally, e.g., through 
impacting deepwater formation that influences global ocean circulation 
(ACIA 2005, p. 32).
    Sea ice is also an important environmental factor in Arctic marine 
ecosystems. ``Several physical factors combine to make arctic marine 
systems unique including: a very high proportion of continental shelves 
and shallow water; a dramatic seasonality and overall low level of 
sunlight; extremely low water temperatures; presence of extensive areas 
of multi-year and seasonal sea-ice cover; and a strong influence from 
freshwater, coming from rivers and ice melt'' (ACIA 2005, p. 454). Ice 
cover is an important physical characteristic, affecting heat exchange 
between water and atmosphere, and light penetration to organisms in the 
water below. It also helps determine the depth of the mixed layer, and 
provides a biological habitat above, within, and beneath the ice. The 
marginal ice zone, at the edge of the pack ice, is important for 
plankton production and plankton-feeding fish (ACIA 2005, p. 456)

Observed Changes in Arctic Sea Ice

    Sea ice is the defining physical characteristic of the marine 
Arctic environment and has a strong seasonal cycle (ACIA 2005, p. 30). 
There is considerable inter-annual variability both in the maximum and 
minimum extent of sea ice, but it is typically at its maximum extent in 
March and minimum extent in September (Parkinson et al. 1999, p. 20, 
840). In addition, there are decadal and inter-decadal fluctuations to 
sea ice extent due to changes in atmospheric pressure patterns and 
their associated winds, river runoff, and influx of Atlantic and 
Pacific waters (Gloersen 1995, p. 505; Mysak and Manak 1989, p. 402; 
Kwok 2000, p. 776; Parkinson 2000b, p. 10; Polyakov et al. 2003, p. 
2,080; Rigor et al. 2002, p. 2,660; Zakharov 1994, p. 42). Sea ice 
``extent'' is normally defined as the area of the ocean with at least 
15 percent ice coverage, and sea ice ``area'' is normally defined as 
the integral sum of areas actually covered by sea ice

[[Page 28220]]

(Parkinson et al. 1999). ``Area'' is a more precise measure of the 
areal extent of the ice itself, since it takes into account the 
fraction of leads (linear openings or cracks in the ice) within the 
ice, but ``extent'' is more reliably observed (Zhang and Walsh 2006). 
The following sections discuss specific aspects of observed sea ice 
changes of relevance to polar bears.

Summer Sea Ice

    Summer sea ice area and sea ice extent are important factors for 
polar bear survival (see ``Polar Bear-Sea Ice Habitat Relationships'' 
section). Seasonal or first-year ice that remains at the end of the 
summer melt becomes multi-year (or perennial) ice. The amount and 
thickness of perennial ice is an important determinant of future sea 
ice conditions (i.e., gain or loss of ice) (Holland and Bitz 2003; Bitz 
and Roe 2004). Much of the following discussion focuses on summer sea 
ice extent (rather than area).
    Prior to the early 1970s, ice extent was measured with visible-band 
satellite imagery and aircraft and ship reports. With the advent of 
passive microwave (PM) satellite observations, beginning in December 
1972 with a single channel instrument and then more reliably in October 
1978 with a multi-channel instrument, we have a more accurate, 3-decade 
record of changes in summer sea ice extent and area. Over the period 
since October 1978, successive papers have documented an overall 
downward trend in Arctic sea ice extent and area. For example, 
Parkinson et al. (1999) calculated Arctic sea ice extents, areas, and 
trends for late 1978 through the end of 1996, and documented a decrease 
in summer sea ice extent of 4.5 percent per decade. Comiso (2002) 
documented a decline of September minimum sea ice extent of 6.7 percent 
plus or minus 2.4 percent per decade from 1981 through 2000. Stroeve et 
al. (2005) analyzed data from 1978 through 2004, and calculated a 
decline in minimum sea ice extent of 7.7 percent plus or minus 3 
percent per decade. Comiso (2006, p. 72) included observations for 
2005, and calculated a per-decade decline in minimum sea ice extent of 
up to 9.8 percent plus or minus 1.5 percent. Most recently, Stroeve et 
al. (2007, pp. 1-5) estimated a 9.1 percent per-decade decline in 
September sea ice extent for 1979-2006, while Serreze et al. (2007, pp. 
1,533-1,536) calculated a per-decade decline of 8.6 percent plus or 
minus 2.9 percent for the same parameter over the same time period. 
These estimates differ only because Serreze et al. (2007, pp. 1,533-
1,536) normalized the trend by the 1979-2000 mean, in order to be 
consistent with how the National Snow and Ice Data Center \1\ 
calculates its estimates (J. Stroeve, in litt. to the Service, November 
2007). This decline translates to a decrease of 60,421 sq km (23,328 sq 
mi) per year (NSIDC Press Release, October 3, 2006).
---------------------------------------------------------------------------

    \1\ The NSIDC is part of the University of Colorado Cooperative 
Institute for Research in Environmental Sciences (CIRES), is funded 
largely by the National Aeronautics and Space Administration (NASA), 
and is affiliated with the National Oceanic and Atmospheric 
Administration (NOAA) National Geophysical Data Center through a 
cooperative agreement. A large part of NSIDC is the Polar 
Distributed Active Archive Center, which is funded by NASA.
---------------------------------------------------------------------------

    The rate of decrease in September sea ice extent appears to have 
accelerated in recent years, although the acceleration to date has not 
been shown to be statistically significant (C. Bitz, in litt. to the 
Service, November 2007). The years 2002 through 2007 all exceeded 
previous record lows (Stroeve et al. 2005; Comiso 2006; Stroeve et al. 
2007, pp. 1-5; Serreze et al. 2007, pp. 1,533-1,536; NSIDC Press 
Release, October 1, 2007), and 2002, 2005, and 2007 had successively 
lower record-breaking minimum extent values (http://www.nsidc.org). The 
2005 absolute minimum sea ice extent of 5.32 million sq km (2.05 
million sq mi) for the entire Arctic Ocean was a 21 percent reduction 
compared to the mean for 1979 to 2000 (Serreze et al. 2007, pp. 1,533-
1,536). Nghiem et al. (2006) documented an almost 50 percent reduction 
in perennial (multi-year) sea ice extent in the East Arctic Ocean (0 to 
180 degrees east longitude) between 2004 and 2005, while the West 
Arctic Ocean (0 and 180 degrees west longitude) had a slight gain 
during the same period, followed by an almost 70 percent decline from 
October 2005 to April 2006. Nghiem et al. (2007) found that the extent 
of perennial sea ice was significantly reduced by 23 percent between 
March 2005 and March 2007 as observed by the QuikSCAT/SeaWinds 
satellite scatterometer. Nghiem et al. (2006) presaged the extensive 
decline in September sea ice extent in 2007 when they stated: ``With 
the East Arctic Ocean dominated by seasonal ice, a strong summer melt 
may open a vast ice-free region with a possible record minimum ice 
extent largely confined to the West Arctic Ocean.''
    Arctic sea ice declined rapidly to unprecedented low extents in 
summer 2007 (Stroeve et al. 2008). On August 16-17, 2007, Arctic sea 
ice surpassed the previous single-day (absolute minimum) record for the 
lowest extent ever measured by satellite (set in 2005), and the sea ice 
was still melting (NSIDC Arctic Sea Ice News, August 17, 2007). On 
September 16, 2007 (the end of the melt season), the 5-day running mean 
sea ice extent reported by NSIDC was 4.13 million sq km (1.59 million 
sq mi), an all-time record low. This was 23 percent lower than the 
previous record minimum reported in 2005 (see Figure 3) (Stroeve et al. 
2008) and 39 percent below the long-term average from 1979 to 2000 (see 
Figure 4) (NSIDC Press Release, October 1, 2007). Arctic sea ice 
receded so much in 2007 that the so-called ``Northwest Passage'' 
through the straits of the Canadian Arctic Archipelago completely 
opened for the first time in recorded history (NSIDC Press Release, 
October 1, 2007). Based on a time-series of data from the Hadley 
Centre, extending back before the advent of the PM satellite era, sea 
ice extent in mid-September 2007 may have fallen by as much as 50 
percent from the 1950s to 1970s (Stroeve et al. 2008). The minimum 
September Arctic sea ice extent since 1979 is now declining at a rate 
of approximately 10.7 percent per decade (Stroeve et al. 2008), or 
approximately 72,000 sq km (28,000 sq mi) per year (see Figure 3 below) 
(NSIDC Press Release, October 1, 2007).

[[Page 28221]]

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[GRAPHIC] [TIFF OMITTED] TR15MY08.005


[[Page 28222]]


    In August 2007, Arctic sea ice area (recall that ``area'' is a 
different metric than ``extent'' used in the preceding paragraphs) also 
broke the record for the minimum Arctic sea ice area in the period 
since the satellite PM record began in the 1970s (University of 
Illinois Polar Research Group 2007 web site; http://arctic.atmos.uiuc.edu/cryosphere/). The new record was set a full month 
before the historic summer minimum typically occurs, and the record 
minimum continued to decrease over the next several weeks (University 
of Illinois Polar Research Group 2007 web site). The Arctic sea ice 
area reached an historic minimum of 2.92 million sq km (1.13 million sq 
mi) on September 16, 2007, which was 27 percent lower than the previous 
(2005) record Arctic ice minimum area (University of Illinois Polar 
Research Group 2007 web site). In previous record sea ice minimum 
years, ice area anomalies were confined to certain sectors (North 
Atlantic, Beaufort/Bering Sea, etc.), but the character of the 2007 
summer sea ice melt was unique in that it was both dramatic and covered 
the entire Arctic Basin. Atlantic, Pacific, and the central Arctic 
sectors all showed large negative sea ice area anomalies (University of 
Illinois Polar Research Group 2007 web site).
    Two key factors contributed to the September 2007 extreme sea ice 
minimum: thinning of the pack ice in recent decades and an unusual 
pattern of atmospheric circulation (Stroeve et al. 2008). Spring 2007 
started out with less ice and thinner ice than normal. Ice thickness 
estimates from the ICESat satellite laser altimeter instrument 
indicated ice thicknesses over the Arctic Basin in March 2007 of only 1 
to 2 m (3.3 to 6.6 ft) (J. Stroeve, in litt. to the Service, November 
2007). Thinner ice takes less energy to melt than thicker ice, so the 
stage was set for low levels of sea ice in summer 2007 (J. Stroeve, 
quoted in NSIDC Press Release, October 1, 2007). In general, older sea 
ice is thicker than younger ice. Maslanik et al. (2007) used an ice-
tracking computer algorithm to estimate changes in the distribution of 
multi-year sea ice of various ages. They estimated: that the area of 
sea ice at least 5 years old decreased by 56 percent between 1985 and 
2007; that ice at least 7 years old decreased from 21 percent of the 
ice cover in 1988 to 5 percent in 2007; and that sea ice at least 9 
years old essentially disappeared from the central Arctic Basin. 
Maslanik et al. (2007) attributed thinning in recent decades to both 
ocean-atmospheric circulation patterns and warmer temperatures. Loss of 
older ice in the late 1980s to mid-1990s was accentuated by the 
positive phase of the Arctic Oscillation during that period, leading to 
increased ice export through the Fram Strait (Stroeve et al. 2008). 
Another significant change since the late 1990s has been the role of 
the Beaufort Gyre, ``the dominant wind and ice drift regime in the 
central Arctic'' (Maslanik et al. 2007). ``Since the late 1990s * * * 
ice typically has not survived the transit through the southern portion 
of the Beaufort Gyre,'' thus not allowing the ice to circulate in its 
formerly typical clockwise pattern for years while it aged and 
thickened (Maslanik et al. 2007). Temperature changes in the Arctic are 
discussed in detail in the section entitled ``Air and Sea 
Temperatures.''
    Another factor that contributed to the sea ice loss in the summer 
of 2007 was an unusual atmospheric pattern, with persistent high 
atmospheric pressures over the central Arctic Ocean and lower pressures 
over Siberia (Stroeve et al. 2008). The skies were fairly clear under 
the high-pressure cell, promoting strong melt. At the same time, the 
pattern of winds pumped warm air into the region. While the warm winds 
fostered further melt, they also helped push ice away from the Siberian 
shore.

Winter Sea Ice

    The maximum extent of Arctic winter sea ice cover, as documented 
with PM satellite data, has been declining at a lower rate than summer 
sea ice (Parkinson et al. 1999, p. 20,840; Richter-Menge et al. 2006, 
p. 16), but that rate appears to have accelerated in recent years. 
Parkinson and Cavalieri (2002, p. 441) reported that winter sea ice 
cover declined at a rate of 1.8 percent plus or minus 0.6 percent per 
decade for the period 1979 through 1999. More recently, Richter-Menge 
et al. (2006, p. 16) reported that March sea ice extent was declining 
at a rate of 2 percent per decade based on data from 1979-2005, Comiso 
(2006) calculated a decline of 1.9 plus or minus 0.5 percent per decade 
for 1979-2006, and J. Stroeve (in litt. to the Service, November 2007) 
calculated a decline of 2.5 percent per decade, also for 1979-2005.
    In 2005 and 2006, winter maximum sea ice extent set record lows for 
the era of PM satellite monitoring (October 1978 to present). The 2005 
record low winter maximum preceded the then-record low summer minimum 
during the same year, while winter sea ice extent in 2006 was even 
lower than that of 2005 (Comiso 2006). The winter 2007 Arctic sea ice 
maximum was the second-lowest in the satellite record, narrowly missing 
the March 2006 record (NSIDC Press Release, April 4, 2007). J. Stroeve 
(in litt. to the Service, November 2007) calculated a rate of decline 
of 3.0 plus or minus 0.8 percent per decade for 1979-2007.

Cumulative Annual Sea Ice

    Parkinson et al. (1999) documented that Arctic sea ice extent for 
all seasons (i.e., annual sea ice extent) declined at a rate of 2.8 
percent per decade for the period November 1978 through December 1996, 
with considerable regional variation (the greatest absolute declines 
were documented for the Kara and Barents Sea, followed by the Seas of 
Okhotsk and Japan, the Arctic Ocean, Greenland Sea, Hudson Bay, and 
Canadian Archipelago; percentage declines were greatest in the Seas of 
Okhotsk and Japan, at 20.1 percent per decade, and the Kara and Barents 
Seas, at 10.5 percent per decade). More recently, Comiso and Nishio 
(2008) utilized satellite data gathered from late 1978 into 2006, and 
estimated an annual rate decline of 3.4 percent plus or minus 0.2 
percent per decade. They also found regions where higher negative 
trends were apparent, including the Greenland Sea (8.0 percent per 
decade), the Kara/Barents Seas (7.2 percent per decade), the Okhotsk 
Sea (8.7 percent per decade), and Baffin Bay/Labrador Sea (8.6 percent 
per decade). Comiso et al. (2008) included satellite data from 1979 
through early September 2007 in their analyses. They found that the 
trend of the entire sea ice cover (seasonal and perennial sea ice) has 
accelerated from a decline of about 3 percent per decade in 1979-1996 
to a decline of about 10 percent per decade in the last 10 years. 
Statistically significant negative trends in Arctic sea ice extent now 
occur n all calendar months (Serreze et al. 2007, pp. 1,533-1,536).

Sea Ice Thickness

    Sea ice thickness is an important element of the Arctic climate 
system. The sea ice thickness distribution influences the sea ice mass 
budget and ice/ocean/atmosphere exchange (Holland et al. 2006a). Sea 
ice thickness has primarily been measured with upward-looking sonar on 
submarines and on moored buoys; this sonar provides information on ice 
draft, the component of the total ice thickness (about 90 percent) that 
projects below the water surface (Serreze et al. 2007, pp. 1,533-
1,536). Rothrock et al. (1999, p. 3,469) compared sea-ice draft data 
acquired on submarine cruises between 1993 and 1997 with similar data 
acquired between 1958 and 1976, and concluded that the mean sea-ice 
draft at

[[Page 28223]]

the end of the melt season (i.e., perennial or multi-year ice) had 
decreased by about 1.3 m (4.3 ft) in most of the deep water portion of 
the Arctic Ocean. One limitation of submarine sonar data is sparse 
sampling, which complicates interpretation of the results (Serreze et 
al. 2007, pp. 1,533-1,536). Holloway and Sou (2002) noted concerns 
regarding the temporal and spatial sampling of ice thickness data used 
in Rothrock et al. (1999), and concluded from their modeling exercise 
that ``a robust characterization over the half-century time series 
consists of increasing volume to the mid-1960s, decadal variability 
without significant trend from the mid-1960s to the mid-1980s, then a 
loss of volume from the mid-1980s to the mid-1990s.'' Rothrock et al. 
(2003, p. 28) conducted further analysis of the submarine-acquired data 
in conjunction with model simulations and review of other modeling 
studies, and concluded that all models agree that sea ice thickness 
decreased between 0.6 and 0.9 m (2 and 3 ft) from 1987 to 1996. Their 
model showed a modest recovery in thickness from 1996 to 1999. Yu et 
al. (2004, p. 11) further analyzed submarine sonar data and concluded 
that total ice volume decreased by 32 percent from the 1960s and 1970s 
to the 1990s in the central Arctic Basin.
    Fowler et al. (2004) utilized a new technique for combining 
remotely-sensed sea ice motion and sea ice extent to ``track'' the 
evolution of sea ice in the Arctic region from October 1978 through 
March 2003. Their analysis revealed that the area of the oldest sea ice 
(i.e., sea ice older than 4 years) was decreasing in the Arctic Basin 
and being replaced by younger (first-year) ice. The extent of the older 
ice was retreating to a relatively small area north of the Canadian 
Archipelago, with narrow bands spreading out across the central Arctic 
(Fowler et al. 2004, pp. 71-74). More recently, Maslanik et al. (2007) 
documented a substantial decline in the percent coverage of old ice 
within the central Arctic Basin. In 1987, 57 percent of the ice pack in 
this area was 5 or more years old, with 25 percent of this ice at least 
9 years old. By 2007, only 7 percent of the ice pack in this area was 5 
or more years old, and ice at least 9 years old had completely 
disappeared. This is significant because older ice is thicker than 
younger ice, and therefore requires more energy to melt. The reduction 
in the older ice types in the Arctic Basin translates into a reduction 
in mean ice thickness from 2.6 m in March 1987 to 2.0 m in March 2007 
(Stroeve et al. 2008).
    Kwok (2007, p. 1) studied six annual cycles of perennial (multi-
year) Arctic sea ice coverage, from 2000 to 2006, and found that after 
the 2005 summer melt, only about four percent of the thin, first-year 
ice that formed the previous winter survived to replenish the multi-
year sea ice area (NASA/JPL News Release, April 3, 2007). That was the 
smallest amount of multi-year ice replenishment documented in the 
study, and resulted in perennial ice coverage in January 2006 that was 
14 percent smaller than in January 2005. Kwok (2007, p. 1) attributed 
the decline to unusually high amounts of ice exported from the Arctic 
in the summer of 2005, and also to an unusually warm winter and summer 
prior to September 2005.

Length of the Melt Period

    The length of the melt period (or season) affects sea ice cover 
(extent and area) and sea ice thickness (Hakkinen and Mellor 1990; 
Laxon et al. 2003). In general terms, earlier onset of melt and 
lengthening of the melt season result in decreased total sea ice cover 
at the end of summer (i.e., the end of the melt season) (Stroeve et al. 
2005, p. 3). Belchansky et al. (2004, p. 1) found that changes in 
multi-year ice area measured in January were significantly correlated 
with duration of the intervening melt season. Kwok found a correlation 
between the number of freezing and melting temperature days and area of 
multi-year sea ice replenished in a year (NASA/JPL News Release, April 
3, 2007).
    Comiso (2003, p. 3,506), using data for the period 1981-2001, 
calculated that the Arctic sea ice melt season was increasing at a rate 
of 10 to 17 days per decade during that period. Including additional 
years in his analyses, Comiso (2005, p. 50) subsequently found that the 
length of the melt season was increasing at a rate of approximately 
13.1 days per decade. Stroeve et al. (2006 pp. 367-374) analyzed melt 
season duration and melt onset and freeze-up dates from satellite 
passive microwave data for the period 1979 through 2005, and found that 
the Arctic is experiencing an overall lengthening of the melt season at 
a rate of about 2 weeks per decade.
    The NSIDC documented a trend of earlier onset of the melt season 
for the years 2002 through 2005; the melt season arrived earliest in 
2005, occurring approximately 17 days before the mean date of onset of 
the melt season (NSIDC 2005, p. 6). In 2007, in addition to the record-
breaking September minimum sea ice extent, NSIDC scientists noted that 
the date of the lowest sea ice extent shifted to later in the year 
(NSIDC Press Release, October 1, 2007). The minimum sea ice extent 
occurred on September 16, 2007; from 1979 to 2000, the minimum usually 
occurred on September 12. This is consistent with a lengthening of the 
melt season.
    Parkinson (2000) documented a clear decrease in the length of the 
sea ice season throughout the Greenland Sea, Kara and Barents Seas, Sea 
of Okhotsk, and most of the central Arctic Basin. On the basis of 
observational data, Stirling et al. (cited in Derocher et al. 2004) 
calculated that break-up of the annual ice in Western Hudson Bay is 
occurring approximately 2.5 weeks earlier than it did 30 years ago. 
Consistent with these results, Stirling and Parkinson (2006) analyzed 
satellite data for Western Hudson Bay for November 1978 through 2004 
and found that, on average, ice break-up has been occurring about 7 to 
8 days earlier per decade. Stirling and Parkinson (2006) also 
investigated ice break-up in Foxe Basin, Baffin Bay, Davis Strait, and 
Eastern Hudson Bay in Canada. They found that ice break-up in Foxe 
Basin has been occurring about 6 days earlier each decade and ice 
break-up in Baffin Bay has been occurring 6 to 7 days earlier per 
decade. Long-term results from Davis Strait were not conclusive, 
particularly because the maximum percentage of ice cover in Davis 
Strait varies considerably more between years than in western Hudson 
Bay, Foxe Basin, or Baffin Bay. Conversely, Stirling and Parkinson 
(2006) documented a negative short-term trend from 1991 to 2004 in 
Davis Strait. In eastern Hudson Bay, there was not a statistically 
significant trend toward earlier break-up.

Understanding Observed Declines in Arctic Sea Ice

    The observed declines in the extent of Arctic sea ice are well 
documented, and more pronounced in the summer than in the winter. There 
is also evidence that the rate of sea ice decline is increasing. This 
decline in sea ice is of great importance to our determination 
regarding the status of the polar bear. Understanding the causes of the 
decline is also of great importance in assessing what the future might 
hold for Arctic sea ice, and, thus, considerable effort has been 
devoted to enhancing our understanding. This understanding will inform 
our determination regarding the status of the polar bear within the 
foreseeable future as determined in this rule.
    In general terms, sea ice declines can be attributed to three 
conflated factors: warming, atmospheric changes (including circulation 
and clouds), and changes in oceanic circulation (Stroeve and Maslowski 
2007). Serreze et al.

[[Page 28224]]

(2007, pp. 1,533-1,536) characterize the decline of sea ice as a 
conflation of thermodynamic and dynamic processes: ``Thermodynamic 
processes involve changes in surface air temperature (SAT), radiative 
fluxes, and ocean conditions. Dynamic processes involve changes in ice 
circulation in response to winds and ocean currents.'' In the following 
paragraphs we discuss warming, changes in the atmosphere, and changes 
in oceanic circulation, followed by a synthesis. It is critically 
important that we understand the dynamic forces that govern all aspects 
of sea ice given the polar bear's almost exclusive reliance on this 
habitat.

Air and Sea Temperatures

    Estimated rates of change in surface air temperature (SAT) over the 
Arctic Ocean over the past 100 or more years vary depending on the time 
period, season, and data source used (Serreze et al. 2007, pp. 1,533-
1,536). Serreze et al. (2007, pp. 1,533-1,536) note that, although 
natural variability plays a large role in SAT variations, the overall 
pattern has been one of recent warming.
    Polyakov et al. (2003) compiled SAT trends for the maritime Arctic 
for the period 1875 through 2000 (as measured by coastal land stations, 
drifting ice stations, and Russian North Pole stations) and found that, 
since 1875, the Arctic has warmed by 1.2 degrees Celsius (C), an 
average warming of 0.095 degree C per decade over the entire period, 
and an average warming of 0.05  0.04 degree C per decade 
during the 20th century. The increases were greatest in winter and 
spring, and there were two relative maxima during the century (the late 
1930s and the 1990s). The ACIA analyzed land-surface air temperature 
trends as recorded in the Global Historical Climatology Network (GHCN) 
database, and documented a statistically significant warming trend of 
0.09 degree C per decade during the period 1900-2003 (ACIA 2005, p. 
35). For periods since 1950, the rate of temperature increase in the 
marine Arctic documented in the GHCN (ACIA 2005, p. 35) is similar to 
the increase noted by Polyakov et al. (2003).
    Rigor et al. (2000) documented positive trends in SAT for 1979 to 
1997; the trends were greatest and most widespread in spring. Comiso 
(2006) analyzed data from the Advanced Very High Resolution Radiometer 
(AVHRR) for 1981 to 2005, and documented an overall warming trend of 
0.54  0.11 degrees C per decade over sea ice. Comiso noted 
that ``it is apparent that significant warming has been occurring in 
the Arctic but not uniformly from one region to another.'' The Serreze 
et al. (2007, pp. 1,533-1,536) assessment of data sets from the 
National Centers for Environmental Prediction and the National Center 
for Atmospheric Research indicated strong surface and low-level warming 
for the period 2000 to 2006 relative to 1979 to 1999, consistent with 
the observed sea ice losses.
    Stroeve and Maslowski (2007) noted that anomalously high 
temperatures have been consistent throughout the Arctic since 2002. 
Further support for warming comes from studies indicating earlier onset 
of spring melt and lengthening of the melt season (e.g., Stroeve et al. 
2006, pp. 367-374), and data that point to increased downward radiation 
toward the surface, which is linked to increased cloud cover and water 
vapor (Francis and Hunter 2006, cited in Serreze et al. 2007, pp. 
1,533-1,536).
    According to the IPCC AR4 (IPCC 2007, p. 36), 11 of 12 years from 
1995 to 2006 (the exception being 1996) were among the 12 warmest years 
on record since 1850; 2005 and 1998 were the warmest two years in the 
instrumental global surface air temperature record since 1850. Surface 
temperatures in 1998 were enhanced by the major 1997-1998 El 
Ni[ntilde]o but no such large-scale atmospheric anomaly was present in 
2005. The IPCC AR4 concludes that the ``warming in the last 30 years is 
widespread over the globe, and is greatest at higher northern latitudes 
(IPCC 2007, p. 37).'' Further, the IPCC AR4 states that greatest 
warming has occurred in the northern hemisphere winter (December, 
January, February) and spring (March, April, May). Average Arctic 
temperatures have been increasing at almost twice the rate of the rest 
of the world in the past 100 years. However, Arctic temperatures are 
highly variable. A slightly longer Arctic warm period, almost as warm 
as the present, was observed from 1925 to 1945, but its geographical 
distribution appears to have been different from the recent warming 
since its extent was not global.
    Finally, Comiso (2005, p. 43) determined that for each 1 degree C 
increase in surface temperature (global average) there is a 
corresponding decrease in perennial sea ice cover of about 1.48 million 
sq km (0.57 million sq mi).

Changes in Atmospheric Circulation

    Links have also been established between sea ice loss and changes 
in sea ice circulation associated with the behavior of key atmospheric 
patterns, including the Arctic Oscillation (AO; also called the 
Northern Annular Mode (NAM)) (e.g., Thompson and Wallace 2000; 
Limpasuvan and Hartmann 2000) and the more regional, but closely 
related North Atlantic Oscillation (NAO; e.g., Hurrell 1995). First 
described in 1998 by atmospheric scientists David Thompson and John 
Wallace, the Arctic Oscillation is a measure of air-pressure and wind 
patterns in the Arctic. In the so-called ``positive phase'' (or high 
phase), air pressure over the Arctic is lower than normal and strong 
westerly winds occur in the upper atmosphere at high latitudes. In the 
so-called ``negative phase'' (or low phase), air pressure over the 
Arctic is higher than normal, and the westerly winds are weaker.
    Rigor et al. (2002, cited in Stroeve and Maslowski 2007) showed 
that when the AO is positive in winter, altered wind patterns result in 
more offshore ice motion and ice divergence along the Siberian and 
Alaskan coastlines; this leads to the production of more extensive 
areas of thinner, first-year ice that requires less energy to melt. 
Rigor and Wallace (2004, cited in Deweaver 2007) suggested that the 
recent reduction in September ice extent is a delayed reaction to the 
export of multi-year ice during the high-AO winters of 1989 through 
1995. They estimated that the recovery of sea ice to its normal extent 
should take between 10 and 15 years. However, Rigor and Wallace (2004) 
estimated that the combined winter and summer AO-indices can explain 
less than 20 percent of the variance in summer sea ice extent in the 
western Arctic Ocean where most of the recent reductions in sea ice 
cover have occurred. The notion that AO-related export of multi-year 
ice from the Arctic is the principal cause of observed declines in 
Arctic sea ice extent has been questioned by several authors, including 
Overland and Wang (2005), Comiso (2006), Stroeve and Maslowski (2007), 
Serreze et al. (2007, pp. 1,533-1,536), and Stroeve et al. (2008) who 
note that sea ice extent has not recovered despite the return of the AO 
to a more neutral state since the late 1990s. Overland and Wang (2005) 
noted that the return of the AO to a more neutral state was accompanied 
by southerly wind anomalies from 2000-2005 which contributed to 
reducing the ice cover over time and ``conditioning'' the Arctic for 
the extensive summer sea ice reduction in 2007 (J. Overland NOAA, pers. 
comm. to FWS, 2007). Maslanik et al. (2007) reached a similar 
conclusion that despite the return of the AO to a more neutral state, 
wind and ice transport patterns that favor reduced ice cover in the 
western and central Arctic continued to play a role in the loss of sea 
ice in those regions. Maslanik et al.

[[Page 28225]]

(2007) believe that circulation patterns such as the Beaufort Gyre, 
which in the past helped to maintain old ice in the Arctic Basin, are 
now acting to export ice, as the multi-year ice is no longer surviving 
the transport through the Chukchi and East Siberian Seas.
    According to DeWeaver (2007): ``Recognizing the need to incorporate 
AO variability into considerations of recent sea ice decline, Lindsay 
and Zhang (2005) used an ocean-sea ice model to reconstruct the sea ice 
behavior of the satellite era and identify separate contributions from 
ice motion and thermodynamics. Similar experiments with similar results 
were also reported by Rothrock and Zhang (2005) and Koberle and Gerdes 
(2003).'' Rothrock and Zhang (2005, cited in Serreze et al. 2007, pp. 
1,533-1,536), using a coupled ice-ocean model, argued that although 
wind forcing was the dominant driver of declining ice thickness and 
volume from the late 1980s through the mid-1990s, the ice response to 
generally rising air temperatures was more steadily downward over the 
study period (1948 to 1999). ``In other words, without wind forcing, 
there would still have been a downward trend in ice extent, albeit 
smaller than that observed'' (Serreze et al. 2007, pp. 1,533-1,536). 
Lindsay and Zhang (2005, cited in Serreze et al. 2007, pp. 1,533-1,536) 
came to similar conclusions in their modeling study: ``Rising air 
temperature reduced ice thickness, but changes in circulation also 
flushed some of the thicker ice out of the Arctic, leading to more open 
water in summer and stronger absorption of solar radiation in the upper 
(shallower depths of the) ocean. With more heat in the ocean, thinner 
ice grows in autumn and winter.''

Changes in Oceanic Circulation

    According to Serreze et al. (2007, pp. 1,533-1,536), it appears 
that changes in ocean heat transport have played a role in declining 
Arctic sea ice extent in recent years. Warm Atlantic waters enter the 
Arctic Ocean through the Fram Strait and Barents Sea (Serreze et al. 
2007, pp. 1,533-1,536). This water is denser than colder, fresher (less 
dense) Arctic surface waters, and sinks (subducts) to form an 
intermediate layer between depths of 100 and 800 m (328 and 2,624 ft) 
(Quadfasel et al. 1991) with a core temperature significantly above 
freezing (DeWeaver 2007; Serreze et al. 2007, pp. 1,533-1,536). 
Hydrographic data show increased import of Atlantic-derived waters in 
the early to mid-1990s and warming of this inflow (Dickson et al. 2000; 
Visbeck et al. 2002). This trend has continued, characterized by 
pronounced pulses of warm inflow (Serreze et al. 2007, pp. 1,533-
1,536). For example, strong ocean warming in the Eurasian Basin of the 
Arctic Ocean in 2004 can be traced to a pulse entering the Norwegian 
Sea in 1997-1998 and passing through Fram Strait in 1999 (Polyakov et 
al. 2007). The anomaly found in 2004 was tracked through the Arctic 
system and took about 1.5 years to travel from the Norwegian Sea to the 
Fram Strait region, and an additional 4.5-5 years to reach the Laptev 
Sea slope (Polyakov et al. 2007).
    Polyakov et al. (2007) reported that mooring-based records and 
oceanographic surveys suggest that a new pulse of anomalously warm 
water entered the Arctic Ocean in 2004. Further Polyakov et al. (2007) 
stated that: ``combined with data from the previous warm anomaly * * * 
this information provides evidence that the Nansen Basin of the Arctic 
Ocean entered a new warm state. These two warm anomalies are 
progressing towards the Arctic Ocean interior * * * but still have not 
reached the North Pole observational site. Thus, observations suggest 
that the new anomalies will soon enter the central Arctic Ocean, 
leading to further warming of the polar basin. More recent data, from 
summer 2005, showed another warm anomaly set to enter the Arctic Ocean 
through the Fram Strait (Walczowski and Piechura 2006). These inflows 
may promote ice melt and discourage ice growth along the Atlantic ice 
margin (Serreze et al. 2007, pp. 1,533-1,536).
    Once Atlantic water enters the Arctic Ocean, the cold halocline 
layer (CHL) separating the Atlantic and surface waters largely 
insulates the ice from the heat of the Atlantic layer. Observations 
suggest a retreat of the CHL in the Eurasian basin in the 1990s (Steele 
and Boyd 1998, cited in Serreze et al. 2007, pp. 1,533-1,536). This 
likely increased Atlantic layer heat loss and ice-ocean heat exchange 
(Serreze et al. 2007, pp. 1,533-1,536), which would serve to erode the 
edge of the sea ice on a year-round basis (C. Bitz, in litt. to the 
Service, November 2007). Partial recovery of the CHL has been observed 
since 1998 (Boyd et al. 2002, cited in Serreze et al. 2007, pp. 1,533-
1,536), and future behavior of the CHL is an uncertainty in projections 
of future sea ice loss (Serreze et al. 2007, pp. 1,533-1,536).

Synthesis

    From the previous discussion, surface air temperature warming, 
changes in atmospheric circulation, and changes in oceanic circulation 
have all played a role in observed declines of Arctic sea ice extent in 
recent years.
    According to DeWeaver (2007): ``Lindsay and Zhang (2005) propose a 
three-part explanation of sea ice decline,'' which incorporates both 
natural AO variability and warming climate. In their explanation, a 
warming climate preconditions the ice for decline as warmer winters 
thin the ice, but the loss of ice extent is triggered by natural 
variability such as flushing by the AO. Sea ice loss continues after 
the flushing because of the sea-ice albedo feedback mechanism which 
warms the sea even further. In recent years, flushing of sea ice has 
continued through other mechanisms despite a relaxation of the AO since 
the late 1990s. The sea-ice albedo feedback effect is the result of a 
reduction in the extent of brighter, more reflective sea ice or snow, 
which reflects solar energy back into the atmosphere, and a 
corresponding increase in the extent of darker, more absorbing water or 
land that absorbs more of the sun's energy. This greater absorption of 
energy causes faster melting, which in turn causes more warming, and 
thus creates a self-reinforcing cycle or feedback loop that becomes 
amplified and accelerates with time. Lindsay and Zhang (2005, p. 4,892) 
suggest that the sea-ice albedo feedback mechanism caused a tipping 
point in Arctic sea ice thinning in the late 1980s, sustaining a 
continual decline in sea ice cover that cannot easily be reversed. 
DeWeaver (2007) believes that the work of Lindsay and Zhang (2005) 
suggests that the observed record of sea ice decline is best 
interpreted as a combination of internal variability and external 
forcing (via GHGs), and raises the possibility that the two factors may 
act in concert rather than as independent agents.
    Evidence that warming resulting from GHG forcing has contributed to 
sea ice declines comes largely from model simulations of the late 20th 
century climate. Serreze et al. (2007, pp. 1,533-1,536) summarized 
results from Holland et al. (2006, pp. 1-5) and Stroeve et al. (2007, 
pp. 1-5), and concluded that the qualitative agreement between model 
results and actual observations of sea ice declines over the PM 
satellite era is strong evidence that there is a forced component to 
the decline. This is because each of these models would be in its own 
phase of natural variability and thus could show an increase or 
decrease in sea ice, but the fact that they all show a decrease 
indicates that more than natural variability is involved, i.e., that 
external forcing by GHGs is a factor. In addition, the model results do 
not show a decline if they are not forced with the observed GHGs. 
Serreze et al.

[[Page 28226]]

(2007, pp. 1,533-1,536) concluded: ``These results provide strong 
evidence that, despite prominent contributions of natural variability 
in the observed record, GHG loading has played a role.''
    Hegerl et al. (2007) used a new approach to reconstruct and 
attribute a 1,500-year temperature record for the Northern Hemisphere. 
Based on their analysis to detect and attribute temperature change over 
that period, they estimated that about a third of the warming in the 
first half of the 20th century can be attributed to anthropogenic GHG 
emissions. In addition, they estimated that the magnitude of the 
anthropogenic signal is consistent with most of the warming in the 
second half of the 20th century being anthropogenic.

Observed Changes in Other Key Parameters

Snow Cover on Ice

    Northern Hemisphere snow cover, as documented by satellite over the 
1966 to 2005 period, decreased in every month except November and 
December, with a step like drop of 5 percent in the annual mean in the 
late 1980s (IPCC 2007, p. 43). April snow cover extent in the Northern 
Hemisphere is strongly correlated with temperature in the region 
between 40 and 60 degrees N Latitude; this reflects the feedback 
between snow and temperature (IPCC 2007, p. 43).
    The presence of snow on sea ice plays an important role in the 
Arctic climate system (Powell et al. 2006). Arctic sea ice is covered 
by snow most of the year, except when the ice first forms and during 
the summer after the snow has melted (Sturm et al. 2006). Warren et al. 
(1999, cited in IPCC 2007 Chapter 4) analyzed 37 years (1954-1991) of 
snow depth and density measurements made at Soviet drifting stations on 
multi-year Arctic sea ice. They found a weak negative trend for all 
months, with the largest being a decrease of 8 cm (3.2 in) (23 percent) 
in May.

Precipitation

    The Arctic Climate Impact Assessment (2005) concluded that 
``overall, it is probable that there was an increase in arctic 
precipitation over the past century.'' An analysis of data in the 
Global Historical Climatology Network (GHCN) database indicated a 
significant positive trend of 1.4 percent per decade (ACIA 2005) for 
the period 1900 through 2003. New et al. (2001, cited in ACIA 2005)) 
used uncorrected records and found that terrestrial precipitation 
averaged over the 60 degree to 80 degree N latitude band exhibited an 
increase of 0.8 percent per decade over the period from 1900 to 1998. 
In general, the greatest increases were observed in autumn and winter 
(Serreze et al. 2000). According to the ACIA (2005) calculations: (1) 
during the Arctic warming in the first half of the 20th century (1900-
1945), precipitation increased by about 2 percent per decade, with 
significant positive trends in Alaska and the Nordic region; (2) during 
the two decades of Arctic cooling (1946-1965), the high-latitude 
precipitation increase was roughly 1 percent per decade, but there were 
large regional contrasts with strongly decreasing values in western 
Alaska, the North Atlantic region, and parts of Russia; and (3) since 
1966, annual precipitation has increased at about the same rate as 
during the first half of the 20th century. The ACIA report (2005) notes 
that these trends are in general agreement with results from a number 
of regional studies (e.g., Karl et al. 1993; Mekis and Hogg 1999; 
Groisman and Rankova 2001; Hanssen-Bauer et al. 1997; F[oslash]rland et 
al. 1997; Hanssen-Bauer and F[oslash]rland 1998). In addition to the 
increase, changes in the characteristics of precipitation have also 
been observed (ACIA 2005). Much of the precipitation increase appears 
to be coming as rain, mostly in winter and to a lesser extent in autumn 
and spring. The increasing winter rains, which fall on top of existing 
snow, cause faster snowmelt. Increased rain in late winter and early 
spring could affect the thermal properties of polar bear dens (Derocher 
et al. 2004), thereby negatively impacting cub survival. Increased rain 
in late winter and early spring may even cause den collapse (Stirling 
and Smith 2004).
    According to the IPCC AR4 (2007, pp. 256-258), distinct upward 
trends in precipitation are evident in many regions at higher 
latitudes, especially from 30 to 85 degrees N latitude. Winter 
precipitation has increased at high latitudes, although uncertainties 
exist because of changes in undercatch, especially as snow changes to 
rain (IPCC 2007, p. 258). Annual precipitation for the circumpolar 
region north of 50 degrees N has increased during the past 50 years by 
approximately 4 percent but this increase has not been homogeneous in 
time and space (Groisman et al. 2003, 2005, both cited in IPCC 2007, p. 
258). According to the IPCC AR4: ``Statistically significant increases 
were documented over Fennoscandia, coastal regions of northern North 
America (Groisman et al. 2005), most of Canada (particularly northern 
regions) up until at least 1995 when the analysis ended (Stone et al. 
2000), the permafrost-free zone of Russia (Groisman and Rankova 2001) 
and the entire Great Russian Plain (Groisman et al. 2005, 2007).'' That 
these trends are real, extending from North America to Europe across 
the North Atlantic, is also supported by evidence of ocean freshening 
caused by increased freshwater run-off (IPCC 2007, p. 258).
    Rain-on-snow events have increased across much of the Arctic. For 
example, over the past 50 years in western Russia, rain-on-snow events 
have increased by 50 percent (ACIA 2005). Groisman et al. (2003) 
considered rain-on-snow trends over a 50-year period (1950-2000) in 
high latitudes in the northern hemisphere and found an increasing trend 
in western Russia and decreases in western Canada (the decreasing 
Canadian trend was attributed to decreasing snow pack). Putkonen and 
Roe (2003), working on Spitsbergen Island, where the occurrence of 
winter rain-on-snow events is controlled by the North Atlantic 
Oscillation, demonstrated that these events are capable of influencing 
mean winter soil temperatures and affecting ungulate survival. These 
authors include the results of a climate modeling effort (using the 
earlier-generation Geophysical Fluid Dynamics Laboratory climate model 
and a 1 percent per year increase in CO2 forcing scenario) 
that predicted a 40 percent increase in the worldwide area of land 
affected by rain-on-snow events from 1980-1989 to 2080-2089. Rennert et 
al. (2008) discussed the significance of rain-on-snow events to 
ungulate survival in the Arctic, and used the dataset European Center 
for Medium-range Weather Forecasting (ECMWF) European 40 Year (ERA40) 
Reanalysis (Uppala et al. 2005) to create a climatology of rain-on-snow 
events for thresholds that impact ungulate populations and permafrost. 
In addition to contributing to increased incidence of polar bear den 
collapse, increased rain-on-snow events during the late winter or early 
spring could also damage or eliminate snow-covered pupping lairs of 
ringed seals (the polar bear's principal prey), thereby increasing pup 
exposure and the risk of hypothermia, and facilitating predation by 
polar bears and Arctic foxes. This could negatively impact ringed seal 
recruitment.

Projected Changes in Arctic Sea Ice

Background

    To make projections about future ecosystem effects that could 
result from climate change, one must first make projections of changes 
in physical

[[Page 28227]]

climate parameters based on changes in external factors that can affect 
the physical climate (ACIA 2005). Climate models use the laws of 
physics to simulate the main components of the climate system (the 
atmosphere, ocean, land surface, and sea ice) (DeWeaver 2007), and make 
projections of future climate scenarios-plausible representations of 
future climate-that are consistent with assumptions about future 
emissions of GHGs and other pollutants (these assumptions are called 
``emissions scenarios'') and with present understanding of the effects 
of increased atmospheric concentrations of these components on the 
climate (ACIA 2005).
    Virtually all climate models use emissions scenarios developed as 
part of the IPCC effort; specifically the IPCC's Special Report on 
Emissions Scenarios (SRES) (IPCC 2000) details a number of plausible 
future emissions scenarios based on assumptions on how societies, 
economies, and energy technologies are likely to evolve. The SRES 
emissions scenarios were built around four narrative storylines that 
describe the possible evolution of the world in the 21st century (ACIA 
2005, p.119). Around these four narrative storylines the SRES 
constructed six scenario groups and 40 different emissions scenarios. 
Six scenarios (A1B, A1T, A1FI, A2, B1, and B2) were then chosen as 
illustrative ``marker'' scenarios. These scenarios have been used to 
estimate a range of future GHG emissions that affect the climate. The 
scenarios are described on page 18 of the AR4 Working Group I: Summary 
for Policymakers (IPCC 2007), and in greater detail in the SRES Report 
(IPCC 2000).
    The most commonly-used scenarios for current-generation climate 
modeling are the B1, A1B, and A2 scenarios. In the B1 scenario, 
CO2 concentration is around 549 parts per million (ppm) by 
2100; this is often termed a `low' scenario. In the A1B scenario, 
CO2 concentration is around 717 ppm by the end of the 
century; this is a 'medium' or `middle-of-the-road' scenario. In the A2 
scenario, CO2 concentration is around 856 ppm at the end of 
the 21st century; this is considered a `high' scenario with respect to 
GHG concentrations. It is important to note that the SRES scenarios 
include no additional mitigation initiatives, which means that no 
scenarios are included that explicitly assume the implementation of the 
United Nations Framework Convention on Climate Change (UNFCC) or the 
emission targets of the Kyoto Protocol.
    Of the various types of climate models, the Atmosphere-Ocean 
General Circulation Models (AOGCMs, also known as General Circulation 
Models (GCMs)) are acknowledged as the principal and most rapidly-
developing tools for simulating the response of the global climate 
system to various GHG and aerosol emission scenarios. The climates 
simulated by these models have been verified against observations in 
several model intercomparison programs (e.g., Achuta Rao et al. 2004; 
Randall et al. 2007) and have been found to be generally realistic 
(DeWeaver 2007). Additional confidence in model simulations comes from 
experiments with a hierarchy of simpler models, in which the dominant 
processes represented by climate models (e.g., heat and momentum 
transport by mid-latitude weather systems) can be isolated and studied 
(DeWeaver 2007).
    For projected changes in climate and Arctic sea ice conditions, our 
proposed rule (72 FR 1064) relied primarily on results in the IPCC's 
Third Assessment Report (TAR) (IPCC 2001b), the Arctic Climate Impact 
Assessment (ACIA 2005, p. 99), and selected peer-reviewed papers (e.g., 
Johannessen et al. 2004; Holland et al. 2006, pp. 1-5). The IPCC TAR 
used results derived from 9-AOGCM ensemble (i.e, averaged results from 
9 AOGCMs) and three SRES emissions scenarios (A2, B2, and IS92a). The 
ACIA (2005, p. 99) used a 5-AOGCM ensemble under two SRES emissions 
scenarios (A2 and B2); however, the B2 emissions scenario was chosen as 
the primary scenario for use in ACIA analyses (ACIA 2005). These 
reports relied on ensembles rather than single models, because ``no one 
model can be chosen as 'best' and it is important to use results from a 
range of models'' (IPCC 2001, Chapter 8). The other peer-reviewed 
papers used in the proposed rule (72 FR 1064) tend to report more-
detailed results from a one or two model simulations using one SRES 
scenario.
    After the proposed rule was published (72 FR 1064), the IPCC 
released its Fourth Assessment Report (AR4) (IPCC 2007), a detailed 
assessment of current and predicted future climates around the globe. 
Projected changes in climate and Arctic sea ice conditions presented in 
the IPCC AR4 have been used extensively in this final rule. The IPCC 
AR4 used results from state-of-the-art climate models that have been 
substantially improved over the models used in the IPCC TAR and ACIA 
reports (M. Holland, NCAR, in litt. to the Service, 2007; DeWeaver 
2007). In addition, the IPCC AR4 used results from a greater number of 
models (23) than either the IPCC TAR or ACIA reports. ``This larger 
number of models running the same experiments allows better 
quantification of the multi-model signal as well as uncertainty 
regarding spread across the models, and also points the way to 
probabilistic estimates of future climate change'' (IPCC 2007, p. 761). 
Finally, the IPCC AR4 used a greater number of emissions scenarios (4) 
than either the IPCC TAR or ACIA reports. The emission scenarios 
considered in the AR4 include A2, A1B, and B1, as well as a ``year 2000 
constant concentration'' scenario; this choice was made solely due to 
the limited computational resources for multi-model simulations using 
comprehensive AOGCMs, and ``does not imply any preference or 
qualification of these three scenarios over the others'' (IPCC 2007, 
p.761). For all of these reasons, there is considerable confidence that 
the AOGCMs used in the IPCC AR4 provide credible quantitative estimates 
of future climate change, particularly at continental scales and above 
(IPCC 2007, p. 591), and we have determined that these results are 
rightly included in the category of best available scientific 
information upon which to base a listing decision for the polar bear.
    In addition to the IPCC AR4 results, this final rule utilizes 
results from a large number of peer-reviewed papers (e.g., Parkinson et 
al. 2006; Zhang and Walsh 2006; Arzel et al. 2006; Stroeve et al. 2007, 
pp. 1-5; Holland et al. 2006, pp. 1-5; Wang et al. 2007, pp. 1,093-
1,107; Overland and Wang 2007a, pp. 1-7; Chapman and Walsh 2007) that 
provide more detailed information on climate change projections for the 
Arctic.

Uncertainty in Climate Models

    The fundamental physical laws reflected in climate models are well 
established, and the models are broadly successful in simulating 
present-day climate and recent climate change (IPCC 2007, cited in 
DeWeaver 2007). For Arctic sea ice, model simulations unanimously 
project declines in areal coverage and thickness due to increased GHG 
concentrations (DeWeaver 2007). They also agree that GHG-induced 
warming will be largest in the high northern latitudes and that the 
loss of sea ice will be much larger in summer than in winter (Meehl et 
al. 2007, cited in DeWeaver 2007). However, despite the qualitative 
agreement among climate model projections, individual model results for 
Arctic sea ice decline span a considerable range (DeWeaver 2007). Thus, 
projections from models are often expressed in terms of the typical

[[Page 28228]]

behavior of a group (ensemble) of simulations (e.g., Arzel et al. 2006; 
Flato et al. 2004; Holland et al. 2006, pp. 1-5).
    DeWeaver (2007) presents a detailed analysis of uncertainty 
associated with climate models and their projections for Arctic sea ice 
conditions. He concludes that two main sources of uncertainty should be 
considered in assessing Arctic sea ice simulations: uncertainties in 
the construction of climate models and unpredictable natural 
variability of the climate system. DeWeaver (2007) states that while 
most aspects of climate simulations have some degree of uncertainty, 
projections of Arctic climate change have relatively higher 
uncertainty. This higher level of uncertainty is, to some extent, a 
consequence of the smaller spatial scale of the Arctic, since climate 
simulations are believed to be more reliable at continental and larger 
scales (Meehl et al. 2007, IPCC 2007, both cited in DeWeaver 2007). The 
uncertainty is also a consequence of the complex processes that control 
the sea ice, and the difficulty of representing these processes in 
climate models. The same processes which make Arctic sea ice highly 
sensitive to climate change, the ice-albedo feedback in particular, 
also make sea ice simulations sensitive to any uncertainties in model 
physics (e.g., the representation of Arctic clouds) (DeWeaver 2007).
    DeWeaver (2007) also discusses natural variability of the climate 
system. He states that the atmosphere, ocean, and sea ice comprise a 
``nonlinear chaotic system'' with a high level of natural variability 
unrelated to external climate forcing. Thus, even if climate models 
perfectly represented all climate system physics and dynamics, inherent 
climate unpredictability would limit our ability to issue highly, 
detailed forecasts of climate change, particularly at regional and 
local spatial scales, into the middle and distant future (DeWeaver 
2007).
    DeWeaver (2007) states that the uncertainty in model simulations 
should be assessed through detailed model-to-model and model-to-
observation comparisons of sea ice properties like thickness and 
coverage. In principle, inter-model sea ice variations are attributable 
to differences in model construction, but attempts to relate simulation 
differences to specific model differences generally have not been 
successful (e.g., Flato et al. 2004, cited in DeWeaver 2007). A 
practical consequence of uncertainty in climate model simulations of 
sea ice is that a mean and spread of an ensemble of simulations should 
be considered in deciding the likely fate of Arctic sea ice. Some 
model-to-model variation (or spread) in future sea ice behaviors is 
expected even among high-quality simulations due to natural 
variability, but spread that is a consequence of poor simulation 
quality should be avoided. Thus, it is desirable to define a selection 
criterion for membership in the ensemble, so that only those models 
that demonstrate sufficient credibility in present-day sea ice 
simulation are included. Fidelity in sea ice hindcasts (i.e., the 
ability of models to accurately simulate past to present-day sea ice 
conditions) is an important consideration. This same perspective is 
shared by other researchers, including Overland and Wang (2007a, p. 1), 
who state: ``Our experience (Overland and Wang 2007b) as well as others 
(Knutti et al. 2006) suggest that one method to increase confidence in 
climate projections is to constrain the number of models by removal of 
major outliers through validating historical simulations against 
observations. This requirement is especially important for the 
Arctic.''

Projection Results in the IPCC TAR and ACIA

    This section briefly summarizes the climate model projections of 
the IPCC TAR and the ACIA, the principal reports used in the proposed 
rule (72 FR 1064), while the following section presents detailed 
results published subsequent to those reports, including in the IPCC 
AR4.
    All models in the IPCC TAR predicted continued Arctic warming and 
continued decreases in the Arctic sea ice cover in the 21st century due 
to increasing global temperatures, although the level of increase 
varied between models. The TAR projected a global mean temperature 
increase of 1.4 degree C by the mid-21st century compared to the 
present climate for both the A2 and B2 scenarios (IPCC 2001b). Toward 
the end of the 21st century (2071 to 2100), the mean change in global 
average surface air temperature, relative to the period 1961-1990, was 
projected to be 3.0 degrees C (with a range of 1.3 to 4.5 degrees C) 
for the A2 scenario, and 2.2 degrees C (with a range of 0.9 to 3.4 
degrees C) for the B2 scenario. Relative to glacier and sea ice change, 
the TAR reported that ``The representation of sea-ice processes 
continues to improve, with several climate models now incorporating 
physically based treatments of ice dynamics * * *. Glaciers and ice 
caps will continue their widespread retreat during the 21st century and 
Northern Hemisphere snow cover and sea ice are projected to decrease 
further.''
    The ACIA concluded that, for both the A2 and B2 emissions 
scenarios, models projected mean temperature increases of 2.5 degrees C 
for the region north of 60 degrees N latitude by the mid-21st century 
(ACIA 2005, p. 100). By the end of the 21st century, Arctic temperature 
increases were projected to be 7 degrees C and 5 degrees C for the A2 
and B2 scenarios, respectively, compared to the present climate (ACIA 
2005, p. 100). Greater warming was projected for the autumn and winter 
than for the summer (ACIA 2005, p. 100).
    The ACIA utilized projections from the five ACIA-designated AOGCMs 
to evaluate changes in sea ice conditions for three points in time 
(2020, 2050, and 2080) relative to the climatological baseline (2000) 
(ACIA 2005, p. 192). In 2020, the duration of the sea ice freezing 
period was projected to be shorter by 10 days; winter sea ice extent 
was expected to decline by 6 to 10 percent from baseline conditions; 
summer sea ice extent was expected to decline such that continental 
shelves were likely to be ice free; and there would be some reduction 
in multi-year ice, especially on shelves (ACIA 2005, Table 9.4). In 
2050, the duration of the sea ice freezing period was projected to be 
shorter by 15 to 20 days; winter sea ice extent was expected to decline 
by 15 to 20 percent; summer sea ice extent was expected to decline 30 
to 50 percent from baseline conditions; and there would be significant 
loss of multi-year ice, with no multi-year ice on shelves. In 2080, the 
duration of the sea ice freezing period was projected to be shorter by 
20 to 30 days; winter sea ice extent was expected to decline such that 
there probably would be open areas in the high Arctic (Barents Sea and 
possibly Nansen Basin); summer sea ice extent was expected to decline 
50 to 100 percent from baseline conditions; and there would be little 
or no multi-year ice.
    According to ACIA (2005, p. 193), one model indicated an ice-free 
Arctic during September by the mid-21st century, but this model 
simulated less than half of the observed September sea-ice extent at 
the start of the 21st century. None of the other models projected ice-
free summers in the Arctic by 2100, although the sea-ice extent 
projected by two models decreased to about one-third of initial (2000) 
and observed September values by 2100.

Projection Results in the IPCC AR4 and Additional Projections

    The IPCC AR4, released a few months after publication of our 
proposed listing

[[Page 28229]]

rule for the polar bear (72 FR 1064), presents results from state-of-
the-art climate models that are substantially improved over models used 
in the IPCC TAR and ACIA reports (M. Holland, NCAR, in litt. to the 
Service FWS, 2007; DeWeaver 2007). Results of the AR4 are presented in 
this section, followed by discussion of several key, peer-reviewed 
articles that discuss results presented in the AR4 in greater detail or 
use AR4 simulations to conduct additional, in-depth analyses.
    In regard to surface air temperature changes, the IPCC AR4 states 
that the range of expected globally averaged surface air temperature 
warming shows limited sensitivity to the choice of SRES emissions 
scenarios for the early 21st century (between 0.64 and 0.69 degrees C 
for 2011 to 2030 compared to 1980 to 1999, a range of only 0.05 
[deg]C), largely due to climate change that is already committed (IPCC 
2007, p. 749). By the mid-21st century (2046-2065), the choice of SRES 
scenario becomes more important for globally averaged surface air 
temperature warming (with increases of 1.3 degree C for the B1 
scenario, 1.8 degree C for A1B, and 1.7 degree C for A2). During this 
time period, about a third of that warming is projected to be due to 
climate change that is already committed (IPCC 2007, p. 749).
    The ``limited sensitivity'' of the results is because the state-of-
the-art climate models used in the AR4 have known physics in connecting 
increases in GHGs to temperature increases through radiation processes 
(Overland and Wang 2007a, pp. 1-7, cited in J. Overland, NOAA, in litt. 
to the Service, 2007), and the GHG levels used in the SRES emissions 
scenarios are relatively similar until around 2040-2050 (see Figure 5). 
Because increases in GHGs have lag effects on climate and projections 
of GHG emissions can be extrapolated with greater confidence over the 
next few decades, model results projecting out for the next 40 to 50 
years (near-term climate change estimates) have greater credibility 
than results projected much further into the future (long-term climate 
change) (J. Overland, NOAA, in litt. to the Service, 2007). Thus, the 
uncertainty associated with emissions is relatively smaller for the 45-
year ``foreseeable future'' for the polar bear listing. After 2050, 
uncertainty associated with various climate mechanisms and policy/
societal changes begins to increase, as reflected in the larger 
confidence intervals around the trend lines in Figure 5 beyond 2050.
[GRAPHIC] [TIFF OMITTED] TR15MY08.006


[[Page 28230]]


    However, even if GHG emissions had stabilized at 2000 levels, the 
global climate system would already be committed to a warming trend of 
about 0.1 degree C per decade over the next two decades, in the absence 
of large changes in volcanic or solar forcing. Meehl et al. (2006) 
conducted climate change scenario simulations using the Community 
Climate System Model, version 3 (CCSM3, National Center for Atmospheric 
Research), with all GHG emissions stabilized at 2000 levels, and found 
that the global climate system would already be committed to 0.40 
degree C more warming by the end of the 21st century.
    With respect to warming in the Arctic itself, the AR4 concludes: 
``At the end of the 21st century, the projected annual warming in the 
Arctic is 5 degrees C, estimated by the multi-model A1B ensemble mean 
projection'' (see IPCC 2007, p. 908, Fig. 11.21). The across-model 
range for the A1B scenario varied from 2.8 to 7.8 degrees C. Larger 
mean warming was found for the A2 scenario (5.9 degrees C), and smaller 
mean warming was found for the B1 scenario (3.4 degrees C); both with 
proportional across-model ranges. Chapman and Walsh (2007, cited IPCC 
2007, p. 904) concluded that the across-model and across-scenario 
variability in the projected temperatures are both considerable and of 
comparable amplitude.
    In regard to changes in sea ice, the IPCC AR4 concludes that, under 
the A1B, A2, and B1 SRES emissions scenarios, large parts of the Arctic 
Ocean are expected to be seasonally ice free by the end of the 21st 
century (IPCC 2007, p. 73). Some projections using the A2 and A1B 
scenarios achieve a seasonally ice-free Arctic by as early as 2080-2090 
(IPCC 2007, p.771, Figure 10.13a, b). Sea ice reductions are greater in 
summer than winter, thus it is summer sea ice cover that is projected 
to be lost in some models by 2080-2090, not winter sea ice cover. The 
reduction in sea ice cover is accelerated by positive feedbacks in the 
climate system, including the ice-albedo feedback (which allows open 
water to receive more heat from the sun during summer, the insulating 
effect of sea ice is reduced and the increase in ocean heat transport 
to the Arctic further reduces ice cover) (IPCC 2007, p. 73).
    While the conclusions of the IPCC TAR and AR4 are similar with 
respect to the Arctic, the confidence level associated with independent 
reviews of AR4 is greater, owing to improvements in the models used and 
the greater number of models and emissions scenarios considered (J. 
Overland, NOAA, in litt. to the Service, 2007). Climate models still 
have challenges modeling some of the regional differences caused by 
changing decadal climate patterns (e.g., Arctic Oscillation). To help 
improve the models further, the evaluation of AR4 models has been on-
going both for how well they represent conditions in the 20th century 
and how their predicted results for the 21st century compare (Parkinson 
et al. 2006; Zhang and Walsh 2006; Arzel et al. 2006; Stroeve et al. 
2007, pp. 1-5; Holland et al. 2006, pp. 1-5; Wang et al. 2007, pp. 
1,093-1,107; Chapman and Walsh 2007).
    Arzel et al. (2006) and Zhang and Walsh (2006) evaluate the sea ice 
results from the IPCC AR4 models in more detail. Arzel et al. (2006) 
investigated projected changes in sea ice extent and volume simulated 
by 13 AOGCMs (also known as GCMs) driven by the SRES A1B emissions 
scenario. They found that the models projected an average relative 
decrease in sea ice extent of 15.4 percent in March, 61.7 percent in 
September, and 27.7 percent on an annual basis when comparing the 
periods 1981-2000 and 2081-2100; the average relative decrease in sea 
ice volume was 47.8 percent in March, 78.9 percent in September, and 
58.8 percent on an annual basis when comparing the periods 1981-2000 
and 2081-2100. More than half the models (7 of 13) reach ice-free 
September conditions by 2100, as reported in some previous studies 
(Gregory et al. 2002, Johannessen et al. 2004, both cited in Arzel et 
al. 2006).
    Zhang and Walsh (2006) investigated changes in sea ice area 
simulated by 14 AOGCMs driven by the SRES A1B, A2, and B1 emissions 
scenarios. They found that the annual mean sea ice area during the 
period 2080-2100 would be decreased by 31.1 percent in the A1B 
scenario, 33.4 percent in the A2 scenario, and 21.6 percent in the B1 
scenario relative to the observed sea ice area during the period 1979-
1999. They further determined that the area of multi-year sea ice 
during the period 2080-2100 would be decreased by 59.7 percent in the 
A1B scenario, 65.0 percent in the A2 scenario, and 45.8 percent in the 
B1 scenario relative to the ensemble mean multi-year sea ice area 
during the period 1979-1999.
    Dumas et al. (2006) generated projections of future landfast ice 
thickness and duration for nine sites in the Canadian Arctic and one 
site on the Labrador coast using the Canadian Centre for Climate 
Modelling and Analysis global climate model (CGCM2). For the Canadian 
Arctic sites the mean maximum ice thickness is projected to decrease by 
roughly 30 cm (11.8 in) from 1970-1989 to 2041-2060 and by roughly 50-
55 cm (19.7-21.7 in) from 1970-1989 to 2081-2100. Further, they 
projected a reduction in the duration of sea ice cover of 1 and 2 
months by 2041-2060 and 2081-2100, respectively, from the baseline 
period of 1970-1989. In addition simulated changes in freeze-up and 
break-up revealed a 52-day later freeze-up and 30-day earlier break-up 
by 2081-2100.
    Holland et al. (2006, pp. 1-5) analyzed an ensemble of seven 
projections of Arctic summer sea ice from the Community Climate System 
Model, version 3 (CCSM3; National Center for Atmospheric Research, USA) 
utilizing the SRES A1B emissions scenario. CCSM3 is the model that 
performed best in simulating the actual observations for Arctic ice 
extent over the PM satellite era (Stroeve et al. 2007, pp. 1-5). 
Holland et al. (2006, pp. 1-5) found that the CCSM3 simulations 
compared well to actual observations for Arctic ice extent over the PM 
satellite era, including the rate of its recent retreat. They also 
found that the simulations did not project that sea ice retreat would 
continue at a constant rate into the future. Instead, the CCSM3 
simulations indicate abrupt shifts in the ice cover, with one CCSM3 
simulation showing an abrupt transition starting around 2024 with 
continued rapid retreat for around 5 years. Every CCSM3 run had at 
least one abrupt event (an abrupt event being defined as a time when a 
5-year running mean exceeded three times the 2001-2005 observed 
retreat) in the 21st century, indicating that near ice-free Septembers 
could be reached within 30-50 years from now.
    Holland et al. (2006, pp. 1-5) also discussed results from 15 
additional models used in the IPCC AR4, and concluded that 6 of 15 
other models ``exhibit abrupt September ice retreat in the A1B scenario 
runs.'' The length of the transition varied from 3 to 8 years among the 
models. Thus, in these model simulations, it was found that once the 
Arctic ice pack thins to a vulnerable state, natural variability can 
trigger an abrupt loss of the ice cover so that seasonally ice-free 
conditions can happen within a decade's time (J. Stroeve, in litt. to 
the Service, November 2007).
    Finally, Holland et al. (2006, pp. 1-5) noted that the emissions 
scenario used in the model affected the likelihood of future abrupt 
transitions. In models using the SRES B1 scenario (i.e., with GHG 
levels increasing at a slower rate), only 3 of 15 models show abrupt 
declines lasting from 3 to 5 years. In models using the A2 scenario 
(i.e., with

[[Page 28231]]

GHG levels increasing at a faster rate), 7 of 11 models with available 
data obtain an abrupt retreat in the ice cover; the abrupt events last 
from 3 to 10 years (Holland et al. 2006, pp. 1-5).
    In order to increase confidence in climate model projections, 
several studies have sought to constrain the number of models used by 
validating climate change in the models simulations against actual 
observations (Knutti et al. 2006; Hall and Ou 2006). The concept is to 
create a shorter list of ``higher confidence'' models by removing 
outlier model projections that do not perform well when compared to 
20th century observational data (Overland and Wang 2007a, pp. 1-7). 
This has been done for temperatures (Wang et al. 2007, pp. 1,093-
1,107), sea ice (Overland and Wang 2007a, pp. 1-7; Stroeve et al. 2007, 
pp. 1-5), and sea level pressure (SLP; defined as atmospheric pressure 
at sea level) and precipitation (Walsh and Chapman, pers. comm. with J. 
Overland, NOAA, cited in litt. to the Service, 2007).
    Overland and Wang (2007a, pp. 1-7) investigated future regional 
reductions in September sea ice area utilizing a subset of AR4 models 
that closely simulate observed regional ice concentrations for 1979-
1999 and were driven by the A1B emissions scenario. They used a 
selection criterion, similar to Stroeve et al. (2007, pp. 1-5), to 
constrain the number of models used by removing outliers so as to 
increase confidence in the projections used. Out of an initial set of 
20 potential models, 11 models were retained for the Arctic-wide area, 
4 were retained for the Kara/Laptev Sea area, 8 were retained for the 
East Siberian/Chukchi Sea, and 11 were retained for the Beaufort Sea 
(Overland and Wang 2007a, pp. 1-7). Using these constrained subsets, 
Overland and Wang (2007a, pp. 1-7) found that there is: ``considerable 
evidence for loss of sea ice area of greater than 40 percent by 2050 in 
summer for the marginal seas of the Arctic basin. This conclusion is 
supported by consistency in the selection of the same models across 
different regions, and the importance of thinning ice and increased 
open water at mid-century to the rate of ice loss.'' More specifically, 
Overland and Wang (2007a, pp. 1-7) found that ``By 2050, 7 of 11 models 
estimate a loss of 40 percent or greater of summer Arctic ice area. Six 
of 8 models show a greater than 40 percent ice loss in the East 
Siberian/Chukchi Seas and 7 of 11 models show this loss for the 
Beaufort Sea. The percentage of models with major ice loss could be 
considered higher, as two of the models that retain sea ice are from 
the same Canadian source and thus cannot be considered to be completely 
independent. These results present a consistent picture: there is a 
substantial loss of sea ice for most models and regions by 2050'' (see 
Figure 6). With less confidence, they found that the Bering, Okhotsk, 
and Barents seas have a similar 40 percent loss of sea ice area by 2050 
in winter; Baffin Bay/Labrador shows little change compared to current 
conditions (Overland and Wang 2007a, pp. 1-7). Overland and Wang 
(2007a, pp. 1-7) also note that the CCSM3 model (Holland et al. 2006, 
pp. 1-5) is one of the models with the most rapid ice loss in the 21st 
century; this model is also one of the best at simulating historical 
20th century observations (also see Figure 12 in DeWeaver (2007)).

[[Page 28232]]

[GRAPHIC] [TIFF OMITTED] TR15MY08.007

    DeWeaver (2007), applying a similar conceptual approach as Overland 
and Wang (2007a, pp. 1-7) and Stroeve et al. (2007, pp. 1-5), used a 
selection criterion to construct an ensemble of 10 climate models that 
most accurately depicted sea-ice extent, from the 20 models that 
contributed sea ice data to the AR4. This 10-model ensemble was used by 
the USGS for assessing potential polar bear habitat loss (Durner et al. 
2007). DeWeaver's selection criterion was to include only those models 
for which the mean 1953-1995 simulated September sea ice extent is 
within 20 percent of its actual observed value (as taken from the 
Hadley Center Sea Ice and Sea Surface Temperature (HadISST) data set 
(Raynor et al. 2003)). DeWeaver (2007) then investigated the future 
performance of his 10-model

[[Page 28233]]

ensemble driven by the SRES A1B emissions scenario. He found that: all 
10 models projected declines of September sea ice extent of over 30 
percent by the middle of the 21st century (i.e., 2045-2055); 4 of 10 
models projected declines September sea ice in excess of 80 percent by 
mid-21st century; and 7 of 10 models lose over 97 percent of their 
September sea ice by the end of the 21st century (i.e., 2090-2099) 
(DeWeaver 2007).
    Stroeve et al. (2007, pp. 1-5) compared observed Arctic sea ice 
extent from 1953-2006 with 20th and 21st century simulation results 
from an ensemble of 18 AR4 models forced with the SRES A1B emission 
scenario. Like Overland and Wang (2007a) and DeWeaver (2007), Stroeve 
et al. (2007, pp. 1-5) applied a selection criterion to limit the 
number of models used for comparison. Of the original 18 models in the 
ensemble, 13 were selected because their performance simulating 20th 
century September sea ice extent satisfied the selection criterion 
established by the authors (i.e., model simulations for the the period 
1953-1995 had to be within 20 percent of observations). The 
observational record for the Arctic by Stroeve et al. (2007, pp. 1-5) 
made use of a blended record of PM satellite-era (post November 1978) 
and pre-PM satellite era data (early satellite observation, aircraft 
and ship reports) described by Meier et al. (2007, pp. 428-434) and 
spanning the years 1953-2006 (Stroeve et al. 2007, pp. 1-5).
    Stroeve et al.'s (2007, pp. 1-5) results revealed that the observed 
trend of September sea ice from 1953-2006 (a decline of 7.8  0.6 percent per decade) is three times larger than the 13-model 
mean trend (a decline of 2.5  0.2 percent per decade). In 
addition, none of the 13 models or their individual ensemble members 
has trends in September sea ice as large as the observed trend for the 
entire observation period (1953-2006) or the 11-year period 1995-2006 
(Stroeve et al. 2007, pp. 1-5) (see Figure 7). March sea ice trends are 
not as dramatic, but the modeled decreases are still smaller than 
observed (Stroeve et al. 2007, pp. 1-5). Stroeve et al. (2007, pp. 1-5) 
offer two alternative interpretations to explain the discrepancies 
between the modeled results and the observational record. The first is 
that the ``observed September trend is a statistically rare event and 
imprints of natural variability strongly dominate over any effect of 
GHG loading'' (Stroeve et al. 2007, pp. 1-5). The second is that, if 
one accepts that the suite of simulations is a representative sample, 
``the models are deficient in their response to anthropogenic forcing'' 
(Stroeve et al. 2007, pp. 1-5). Although there is some evidence that 
natural variability is influencing the sea ice decrease, Stroeve et al. 
(2007, pp. 1-5) believe that ``while IPCC AR4 models incorporate many 
improvements compared to their predecessors, shortcomings remain'' 
(Stroeve et al. 2007, pp. 1-5) when they are applied to the Arctic 
climate system, particularly in modeling Arctic Oscillation variability 
and accurately parameterizing sea ice thickness.
[GRAPHIC] [TIFF OMITTED] TR15MY08.008


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    The observational record indicates that current summer sea ice 
losses appear to be about 30 years ahead of the ensemble of modeled 
values, which suggests that a transition towards a seasonally ice-free 
Arctic might occur sooner than the models indicate (J. Stroeve, in 
litt. to the Service, November 2007). However, Stroeve et al. (2007, 
pp. 1-5) note that the two models that best match observations over the 
PM satellite era-CCSM3 and UKMO--HADGEM1 (Hadley Center for Climate 
Prediction and Research, UK)-incorporate relatively sophisticated sea 
ice models (McLaren et al. 2006 and Meehl et al. 2006, both cited in 
Stroeve et al. 2007, pp. 1-5). The same two models were mentioned by 
Gerdes and Koberle (2007) as having the most realistic sea ice 
thickness simulations. If only the results of CCSM3 are considered, as 
in Holland et al. (2006, pp. 1-5), model simulations compare well to 
actual observations for Arctic ice extent over the PM satellite era, 
including the rate of its recent retreat, and simulations of future 
conditions indicate that near ice-free Septembers could be reached 
within 30-50 years from now. If the record ice losses from the summer 
of 2007 are considered, it appears more likely the transition towards a 
seasonal ice cover will occur during the first half of this century 
(Stroeve et al. 2007, pp. 1-5) (see Figure 7). DeWeaver (2007) cautions 
that reliance on a multi-model ensemble is preferred to a single model, 
because the ensemble represents a balance between the desire to focus 
on the most credible models and the competing desire to retain a large 
enough sample to assess the spread of possible outcomes.

Projected Changes in Other Parameters

Air Temperature

    As previously noted, IPCC AR4 simulations using a multi-model 
ensemble and the A1B emissions scenario project that, at the end of the 
21st century (i.e., the period 2080-2099), the Arctic will be 
approximately 5 degrees C warmer, on an annual basis, than in the 
earlier part of 20th century (i.e., the period 1980-1999) (IPCC 2007, 
p. 904). Larger mean warming of 5.9 degrees C is projected for the A2 
scenario, while smaller mean warming of 3.4 degrees C is projected for 
the B1 scenario. J. Overland (NOAA, in litt. to the Service, 2007) and 
associates recently estimated Arctic land temperatures north of 60 
degrees N latitude out to 2050 for the 12 models selected in Wang et 
al. (2007, pp. 1,093-1,107). The average warming from this reduced set 
of models is an increase of 3 degrees C in surface temperatures; the 
range of model projections is 2-4 degrees C, which is an estimate of 
the range of uncertainly in scientists' ability to model Arctic 
climate. An increase in surface temperatures of 3 degrees C by 2050 
will have a major impact on the timing of snowmelt timing (i.e., will 
lead to earlier snowmelt) (J. Overland, NOAA, in litt. to the Service, 
2007).

Precipitation

    The IPCC AR4 simulations show a general increase in precipitation 
over the Arctic at the end of the 21st century (i.e., the period 2080-
2099) in comparison to the 20th century (i.e., the period 1980-1999) 
(IPCC 2007, p. 906). According to the AR4 report (IPCC 2007, p. 906), 
``the precipitation increase is robust among the models and 
qualitatively well understood, attributed to the projected warming and 
related increased moisture convergence.'' Differences between the 
projections for different emissions scenarios are small in the first 
half of the 21st century but increase later. ``The spatial pattern of 
the projected change shows the greatest percentage increase over the 
Arctic Ocean (30 to 40 percent) and smallest (and even slight decrease) 
over the northern North Atlantic (less then 5 percent). By the end of 
the 21st century, the projected change in the annual mean arctic 
precipitation varies from 10 to 28 percent, with an ensemble median of 
18 percent in the A1B scenario'' (IPCC 2007, p. 906). Larger mean 
precipitation increases are found for the A2 scenario with 22 percent; 
smaller mean precipitation increases are found for the B1 scenario with 
13 percent. The percentage precipitation increase is largest in winter 
and smallest in summer, consistent with the projected warming. The 
across-model scatter of the precipitation projections is substantial.
    Putkonen and Roe (2003) presented the results of a global climate 
modeling effort using an older simulation model (from the TAR era) that 
predicted a 40 percent increase in the worldwide area of land affected 
by rain-on-snow events from 1980-1989 to 2080-2089. Rennert et al. 
(2008) refined the estimate in Putkonen and Roe (2003) using daily data 
from a 5-member ensemble of the CCSM3 for the periods 1980-1999 and 
2040-2059. The future scenario indicated increased frequency of rain-
on-snow events in much of Alaska and far eastern Siberia. Decreases in 
rain-on-snow were shown broadly to be due to projected decreases in 
snow pack in the model, not a decrease in rain events.

Previous Federal Actions

    Information about previous Federal actions for the polar bear can 
be found in our proposed rule and 12-month finding published in the 
Federal Register on January 9, 2007 (72 FR 1064), and the ``Summary of 
Comments and Recommendations'' section below.
    On April 28, 2008, the United States District Court for the 
Northern District of California ordered us to publish the final 
determination on whether the polar bear should be listed as an 
endangered or threatened species by May 15, 2008. AS part of its order, 
the Court ordered us to waive the standard 30-day effective date for 
the final determination.

Summary of Comments and Recommendations

    In the January 9, 2007, proposed rule to list the polar bear as a 
threatened species under the Act (72 FR 1064), we opened a 90-day 
public comment period and requested that all interested parties submit 
factual reports, information, and comments that might contribute to 
development of a final determination for polar bear. The public comment 
period closed on April 9, 2007. We contacted appropriate Federal and 
State agencies, Alaska Native Tribes and tribal organizations, 
governments of polar bear range countries (Canada, Russian Federation, 
Denmark (Greenland) and Norway), city governments, scientific 
organizations, peer reviewers (see additional discussion below 
regarding peer review of proposed rule), and other interested parties 
to request comments. The Secretary of the Interior also announced the 
proposed rule and public comment period in a press release issued on 
December 27, 2006. Newspaper articles appeared in the Anchorage Daily 
News, Washington Post, New York Times, Los Angeles Times, Wall Street 
Journal, and many local or regional papers across the country, as well 
as local, national, and international television and radio news 
programs that also notified the public about the proposed listing and 
comment period.
    In response to requests from the public, public hearings were held 
in Washington, DC (March 5, 2007), Anchorage, Alaska (March 1, 2007), 
and Barrow, Alaska (March 7, 2007). These hearings were announced in 
the Federal Register of February 15, 2007 (72 FR 7381), and in the 
Legal Section of the Anchorage Daily News (February 2, 2007). For the 
Barrow, Alaska, public hearing we established teleconferencing 
capabilities to provide an opportunity to receive testimony from 
outlying

[[Page 28235]]

communities. The communities of Kaktovik, Gambell, Kotzebue, 
Shishmaref, and Point Lay, Alaska, participated in this public hearing 
via teleconference. The public hearings were attended by a total of 
approximately 305 people.
    In addition, the Secretary of the Interior, at the time the 
proposal to list the polar bear as a threatened species was announced, 
asked the U.S. Geological Survey (USGS) to assist the Service by 
collecting and analyzing scientific data and developing models and 
interpretations that would enhance the base of scientific data for the 
Service's use in developing the final decision. On September 7, 2007, 
the USGS provided the Service with its analyses in the form of nine 
scientific reports that analyze and integrate a series of studies on 
polar bear population dynamics, range-wide habitat use, and changing 
sea ice conditions in the Arctic. The Service, in turn, reopened the 
public comment period on September 20, 2007 (72 FR 53749), for 15 days 
to notify the public of the availability of these nine reports, to 
announce our intent to consider the reports in making our final listing 
determination, and to ask the public for comments on the reports. On 
the basis of numerous requests from the public, including the State of 
Alaska, the public comment period on the nine reports was extended 
until October 22, 2007 (72 FR 56979).
    While some commenters provided extensive technical comments on the 
reports, a thorough evaluation of comments received found no 
significant scientific disagreement regarding the adequacy or accuracy 
of the scientific information used in the reports. In general, comments 
on the nine reports raised the following themes: assertions that loss 
of sea ice reflects natural variability and not a trend; current 
population status or demographics do not warrant listing; new 
information justifies listing as endangered; and additional information 
is needed because of uncertainty associated with future climate 
scenarios. Commenters also re-iterated concerns and issues raised 
during the public comment period on the proposed rule. New, 
supplementary information became available following publication of the 
proposed rule that supports the climate models used in the nine USGS 
reports, and helps clarify the relative contribution of natural 
variability in future climate scenarios provided by the climate models. 
Comments on the significance of the status and demographic information 
helped clarify our analyses. We find that the USGS reports, in concert 
with additional new information in the literature, clarify our 
understanding of polar bears and their environment and support our 
initial conclusions regarding the status of the species. We believe the 
information presented by USGS and other sources provides a broad and 
solid scientific basis for the analyses and findings in this rule. 
Technical comments received from the public on the USGS reports and our 
responses to those comments are available on our website at: http://alaska.fws.gov/fisheries/mmm/polarbear/issues.htm.
    During the public comment periods, we received approximately 
670,000 comments including letters and post cards (43,513), e-mail 
(626,947), and public hearing testimony (75). We received comments from 
Federal agencies, foreign governments, State agencies, Alaska Native 
Tribes and tribal organizations, Federal commissions, local 
governments, commercial and trade organizations, conservation 
organizations, non-governmental organizations, and private citizens.
    Comments received provided a range of opinions on the proposed 
listing, as follows: (1) unequivocal support for the listing with no 
additional information included; (2) unequivocal support for the 
listing with additional information provided; (3) equivocal support for 
the listing with or without additional information included; (4) 
unequivocal opposition to the listing with no additional information 
included; and (5) unequivocal opposition to the listing with additional 
information included. Outside the public comment periods, we received 
an additional approximately 58,000 cards, petitions, and letters 
pertaining to the proposed listing of the polar bear as a threatened 
species. We reviewed those submissions in detail for content and found 
that they did not provide information that was substantively diiferent 
from what we had already received. Therefore, we determined that 
reopening the comment period was not necessary.
    To accurately review and incorporate the publicly-provided 
information in our final determination, we worked with the eRulemaking 
Research Group, an academic research team at the University of 
Pittsburgh that has developed the Rule-Writer's Workbench (RWW) 
analytical software. The RWW enhanced our ability to review and 
consider the large numbers of comments, including large numbers of 
similar comments, on our proposed listing, allowing us to identify 
similar comments as well as individual ideas, data, recommendations, or 
suggestions on the proposed listing.

Peer Review of the Proposed Rule

    In accordance with our policy published on July 1, 1994 (59 FR 
34270), we solicited expert opinion on information contained in the 
proposed rule from 14 knowledgeable individuals with scientific 
expertise that includes familiarity with the polar bear, the geographic 
region in which the polar bear occurs, Arctic ecology, climatology, and 
Traditional Ecological Knowledge (TEK). The selected polar bear 
specialists included scientists from all polar bear range countries, 
and who work in both academia and in government. The selected climate 
scientists are all active in research and published in Arctic climate 
systems and sea ice dynamics. We sought expertise in TEK from 
internationally recognized native organizations.
    We received responses from all 14 peer reviewers. Thirteen peer 
reviewers found that, in general, the proposed rule represented a 
thorough, clear, and balanced review of the best scientific information 
available from both published and unpublished sources of the current 
status of polar bears. The one exception expressed concern that the 
proposed rule was flawed, biased, and incomplete, that it would do 
nothing to address the underlying issues associated with global 
warming, and that a listing would be detrimental to the Inuit of the 
Arctic. In addition, peer reviewers stated that the background material 
on the ecology of polar bears represents a solid overview of the 
species' ecology relevant to the issue of population status. They also 
stated that information about the five natural or manmade factors that 
may already have affected polar bear populations, or may affect them in 
the future, is presented and evaluated in a fair and balanced way and 
is based on scientifically sound data. They further stated that the 
information as presented justified the conclusion that polar bears face 
threats throughout their range. Several peer reviewers provided 
additional insights to clarify points in the proposed rule, or 
references to recently-published studies that update material in the 
proposal.
    Several peer reviewers referenced the Fourth Assessment Report of 
the Intergovernmental Panel on Climate Change (IPCC AR4). Reports from 
Working Groups I, II, and III of the IPCC AR4 were published earlier in 
2007, and the AR4 Synthesis Report was released in November 2007. The 
Working Group I report updates information in the proposed rule with 
considerable new observational information on global

[[Page 28236]]

climate change, as well results from independent scientific review of 
the results from over 20 current-generation climate models. The 
significance of the Working Group I report, as noted by the peer 
reviewers with climatological expertise, is that the spatial resolution 
and physics of climate models have improved such that uncertainties 
associated with various model components, including prescribed ocean 
conditions, mobile sea ice, clouds/radiation, and land/atmosphere 
exchanges, have been reduced significantly from previous-generation 
models (i.e., those used in the IPCC Third Assessment Report).
    One peer reviewer recommended that appropriate effort should be 
made to integrate the existing sources of Alaska native and other 
indigenous traditional and contemporary ecological knowledge (TEK) into 
our final rule. In addition, the peer reviewer recommended that we 
actively conduct community outreach to obtain this information from 
Alaska villages located within the range of the polar bear.
    One peer reviewer opposed the listing and asserted that existing 
regulatory mechanisms are adequate because the Inuit people will 
account for climate change in setting harvest quotas for polar bears.

Peer Review Comments

    We reviewed all comments received from peer reviewers for 
substantive issues and new information regarding the proposed 
designation of the polar bear as a threatened species. Comments and 
responses have been consolidated into key issues in this section.
    Comment PR1: The importance of sea ice to polar bears is not well 
articulated in the proposed rule, and the consequences of polar bears 
using land as an alternative ``platform'' are understated.
    Our response: We recognize the vital importance of sea ice as 
habitat for polar bears. New information and analyses of specific sea 
ice characteristics important to polar bears has been prepared by USGS 
(Durner et al. 2007), and incorporated into this final rule. 
Projections of changes to sea ice and subsequent effects on resource 
values to polar bears during the foreseeable future have also been 
included in the analyses in this final rule (see ``Polar Bear--Sea Ice 
Habitat Relationships'' section). The consequences of prolonged use of 
terrestrial habitats by polar bears are also discussed in detail in the 
``Effects of Sea Ice Habitat Change on Polar Bears'' section of this 
final rule. We believe that we have objectively assessed these 
consequences, and have not under- or overstated them.
    Comment PR2: The importance of snow cover to successful 
reproduction by polar bears and their primary prey, ringed seals, 
should receive greater emphasis.
    Our response: We recognize the importance of snow cover for denning 
polar bears and pupping ringed seals. Additional new information has 
been included in the sections on climate and the section ``Effects of 
Sea Ice Habitat Changes on Polar Bear Prey,'' ``Maternal Denning 
Habitat,'' and ``Access to and Alteration of Denning Areas'' sections.
    Comment PR3: Harvest programs in Canada provide conservation 
benefits for polar bears and are therefore important to maintain. In 
addition, economic benefits from subsistence hunting and sport hunting 
occur.
    Our response: We recognize the important contribution to 
conservation that scientifically based sustainable use programs can 
have. We further recognize the past significant benefits to polar bear 
management in Canada that have accrued as a result of the 1994 
amendments to the MMPA that allow U.S. citizens who legally sport-
harvest a polar bear from an MMPA-approved population in Canada to 
bring their trophies back into the United States. In addition, income 
from fees collected for trophies imported into the United States are 
directed by statute to support polar bear research and conservation 
programs that have resulted in conservation benefits to polar bears in 
the Chukchi Sea region.
    We recognize that hunting provides direct economic benefits to 
local native communities that derive income from supporting and guiding 
hunters, and also to people who conduct sport hunting programs for U.S. 
citizens. However these benefits cannot be and have not been factored 
into our listing decision for the polar bear.
    We note that, under the MMPA, the polar bear will be considered a 
``depleted'' species on the effective date of this listing. As a 
depleted species, imports could only be authorized under the MMPA if 
the import enhanced the survival of the species or was for scientific 
research. Therefore, authorization for the import of sport-hunted 
trophies will no longer be available under section 104(c)(5) of the 
MMPA. Neither the Act nor the MMPA restricts take beyond the United 
States and the high seas, so otherwise legal take in Canada is not 
affected by the threatened listing.
    Comment PR4: The ability of polar bears to adapt to a changing 
environment needs to be addressed directly, with a focus on the 
importance of rates of environmental change relative to polar bear 
generation time.
    Our response: We have addressed this issue by adding a section to 
the final rule entitled ``Adaptation'' under ``Summary of Factors 
Affecting the Polar Bear.'' Information regarding how polar bears 
survived previous warming events is scant, but some evidence indicates 
that polar bears survived by altering their geographic range, rather 
than evolving through natural selection. The pace at which ice 
conditions are changing and the long generation time of polar bears 
appear to preclude adaptation of new physiological mechanisms and 
physical characteristics through natural selection. In addition, the 
known current physiological, physical, and behavioral characteristics 
of polar bears suggest that behavioral adaptation will be insufficient 
to prevent a pronounced reduction in polar bear distribution, and 
therefore abundance, as a result of declining sea ice. Current evidence 
suggests there is little likelihood that extended periods of torpor, 
consumption of terrestrial foods, or capture of seals in open water 
will be sufficient mechanisms to counter the loss of sea ice as a 
platform for hunting seals. Projections of population trends based upon 
habitat availability, as discussed in the USGS reports by Durner et al. 
(2007) and Amstrup et al. (2007) serve to further clarify the changes 
currently occurring, or expected to occur, as sea ice declines.
    Comment PR5: Harvest levels for some polar bear populations in 
Nunavut (Canada) are not sustainable and should be discussed; however, 
these concerns do not materially alter the primary finding of the 
proposed rule.
    Our response: Although we have some concerns about the current 
harvest levels for some polar populations in Nunavut, we agree that 
these concerns do not materially alter the primary finding of the 
proposed rule. As discussed in Factors B and D, impacts from sport 
hunting or harvest are not threats to the species throughout its range. 
We recognize that, as discussed in detail in this final rule, the 
management of polar bears in Canada and other countries is evolving. We 
believe that our evaluation of the management of the polar bear 
populations in Canada, which includes participation in the annual 
Canadian Polar Bear Technical Committee (PBTC) meeting, provides us 
with the best available information upon which to base future 
management decisions.
    Comment PR6: The most important aspect relative to climate change 
is that

[[Page 28237]]

the most recent assessment of the IPCC (AR4) includes projections that 
climate warming and sea ice decline are likely to continue. This new 
information as well as other new sea ice information needs to be 
incorporated into the final analysis.
    Our response: We agree that new information on climate warming and 
sea ice decline, as discussed in the IPCC AR4 as well as numerous other 
recent scientific papers, is of great significance relative to 
assessing polar bear habitat and population status and trends. Our 
final analysis has been updated to incorporate this new information 
(see ``Sea Ice Habitat'' and ``Polar Bear--Sea Ice Habitat 
Relationships'' sections).
    Comment PR7: Polar bear population status information needs to 
highlight areas of both population decline and population increase, and 
the relationship of the two to overall status of the species.
    Our response: Our final analysis has been updated with new 
population information (see ``Current Population Status and Trend'' 
section).
    Comment PR8: The Service did not consider the impacts of listing 
the polar bear on Inuit economies.
    Our response: Under section 4(b)(1)(A) of the Act, we must base a 
listing decision solely on the best scientific and commercial data 
available as it relates to the listing five factors in section 4(a)(1) 
of the Act. The legislative history of this provision clearly states 
the intent of Congress to ensure that listing decisions are ``* * * 
based solely on biological criteria and to prevent non-biological 
criteria from affecting such decisions * * *'' (House of 
Representatives Report Number 97-835, 97th Congress, Second Session 19 
(1982)). As further stated in the legislative history, ``* * * economic 
considerations have no relevance to determinations regarding the status 
of species * * *'' (Id. at 20).
    Comment PR9: Concerning sport hunting, listing will not help reduce 
take of polar bears.
    Our response: As discussed under Factors B and D below, we 
recognize that sport hunting or other forms of harvest (both legal and 
illegal) may be affecting several polar bear populations, but we have 
determined that overutilization is not a threat to the species 
throughout all or a significant portion of its range. Amstrup et al. 
(2007) found that the impact of harvest on the status of polar bear 
populations is far outweighed by the effects of sea ice losses 
projected into the future. In addition, we have concluded that, in 
general, national and local management regimes established for the 
sustainable harvest of polar bears are adequate. We have determined 
that polar bear harvest by itself, in the absence of declines due to 
changes in sea ice habitat, would not be a sufficient threat to justify 
listing the species in all or a significant portion of its range. 
However, we have also concluded that harvest may become a more 
important factor in the future for populations experiencing nutritional 
stress.
    Comment PR10: Inuit will account for climate change in setting 
subsistence harvest quotas, thus the existing regulatory mechanism is 
adequate.
    Our response: As discussed in this final rule (see ``Polar Bear--
Sea Ice Habitat Relationships'' section), the loss of sea ice habitat 
is considered to threaten the polar bear throughout its range. 
Adjusting harvest levels based on the consequences of habitat loss and 
corresponding reduction in physical condition, recruitment, and 
survival rates is prudent and precautionary, and such adjustments may 
be addressed through existing and future harvest management regimes. 
However, we find that these steps will not be sufficient to offset 
population declines resulting from loss of sea ice habitat.
    Comment PR11: The proposed rule does not adequately reflect the 
state of traditional and contemporary indigenous knowledge regarding 
polar bears and climate change.
    Our response: We have further expanded this rule to include 
information obtained from Kavry's work in Chukotka, Russia (Kochnev et 
al. 2003) and Dowsley and Taylor's work in Nunavut, Canada (Dowsley and 
Taylor 2005), as well as information received during our public 
hearings. Additionally, we have reviewed information available on polar 
bears and climate change from the Alaska Native Science Commission 
(http://www.nativescience.org/issues/climatechange.htm). Discussion 
documents available on their web page generally support the conclusions 
reached in this document; for example, they observe that: ``Saami are 
seeing their reindeer grazing pastures change, Inuit are watching polar 
bears waste away because of a lack of sea ice, and peoples across the 
Arctic are reporting new species, particularly insects'' (http://www.arcticpeoples.org/KeyIssues/ClimateChange/Start.html). Thus, 
traditional and contemporary indigenous knowledge recognizes that 
climate-related changes are occurring in the Arctic and that these 
changes are negatively impacting polar bears.
    Comment PR12: The proposed rule does not sufficiently question the 
reliability of scientific models used. Science is not capable of 
responding to vague terms such as ``it is likely'' ``foreseeable 
future.''
    Our response: Literature used in the proposed rule was the best 
available peer-reviewed scientific information at the time. The 
proposed rule was based largely on results presented in the Arctic 
Climate Impact Assessment (ACIA 2005) and the IPCC Third Assessment 
Report (TAR) (IPCC 2001), plus several individual peer-reviewed journal 
articles. The ACIA and IPCC TAR are synthesis documents that present 
detailed information on climate observations and projections, and 
represent the consensus view of a large number of climate change 
scientists. Thus, they constituted the best scientific information 
available at the time the proposed rule was drafted. The proposed rule 
contained a determination of ``foreseeable future'' (i.e., 45 years) as 
it pertains to a possible listing of polar bears under the Act, and an 
explanation of how that 45-year timeframe was determined. This final 
rule contains the same determination of ``foreseeable future'' (i.e., 
45 years), as well as an explanation of how that 45-year timeframe was 
determined (through a consideration of reliable data on changes 
currently being observed and projected for the polar bear's sea ice 
habitat, and supported by information on the life history (generation 
time) and population dynamics of polar bears). Thus, we disagree with 
the commenter that this is a vague term.
    The final rule has been revised to reflect the most current 
scientific information, including the results of the IPCC AR4 plus a 
large number of peer-reviewed journal articles. The IPCC AR4 assigns 
specific probability values to terms such as ``unlikely,'' ``likely,'' 
and ``very likely.'' We have attempted to use those terms in a manner 
consistent with how they are used in the IPCC AR4.
    We have taken our best effort to identify the limitations and 
uncertainties of the climate models and their projections used in the 
proposed rule. In this final rule, we have provided a more detailed 
discussion to ensure a balanced analysis regarding the causes and 
potential impacts of climate change, and have discussed the limitations 
and uncertainties in the information that provided the basis for our 
analysis and decision.

Public Comments

    We reviewed all comments received from the public for substantive 
issues and new information regarding the proposed designation of the 
polar bear as a threatened species. Comments and

[[Page 28238]]

responses have been consolidated into key issues in this section.

Issue 1: Polar Bear Population Decline

    Comment 1: Current polar bear populations are stable or increasing 
and the polar bear occupies its entire historical range. As such, the 
polar bear is not in imminent danger of extinction and, therefore, 
should not be listed under the Act.
    Our response: We agree that polar bears presently occupy their 
available range and that some polar bear populations are stable or 
increasing. As discussed in the ``Current Population Status and Trend'' 
section of the rule, two polar bear populations are designated by the 
PBSG as increasing (Viscount Melville Sound and M'Clintock Channel); 
six populations are stable (Northern Beaufort Sea, Southern Hudson Bay, 
Davis Strait, Lancaster Sound, Gulf of Bothia, Foxe Basin); five 
populations are declining (Southern Beaufort Sea, Norwegian Bay, 
Western Hudson Bay, Kane Basin, Baffin Bay), and six populations are 
designated as data deficient (Barents Sea, Kara Sea, Laptev Sea, 
Chukchi Sea, Arctic Basin, East Greenland) with no estimate of trend 
(Aars et al. 2006). The two populations with the most extensive time 
series of data, Western Hudson Bay and Southern Beaufort Sea, are 
considered to be declining. The two increasing populations (Viscount 
Melville Sound and M'Clintock Channel) were severely reduced in the 
past as a result of overharvest and are now recovering as a result of 
coordinated international efforts and harvest management.
    The current status must be placed in perspective, however, as many 
populations were declining prior to 1973 due to severe overharvest. In 
the past, polar bears were harvested extensively throughout their range 
for the economic or trophy value of their pelts. In response to the 
population declines, five Arctic nations (Canada, Denmark on behalf of 
Greenland, Norway, Union of Soviet Socialist Republics, and the United 
States), recognized the polar bear as a significant resource and 
adopted an inter-governmental approach for the protection and 
conservation of the species and its habitat, the 1973 Agreement on the 
Conservation of Polar Bears (1973 Agreement). This agreement limited 
the use of polar bears for specific purposes, instructed the Parties to 
manage populations in accordance with sound conservation practices 
based on the best available scientific data, and called the range 
States to take appropriate action to protect the ecosystems upon which 
polar bears depend. In addition, Russia banned harvest in 1956, harvest 
quotas were established in Canada in 1968, and Norway banned hunting in 
1973. With the passage of the MMPA in 1972, the United States banned 
sport hunting of polar bears and limited the hunt to Native people for 
subsistence purposes. As a result of these coordinated international 
efforts and harvest management leading to a reduction in harvest, polar 
bear numbers in some previously-depressed populations have grown during 
the past 30 years.
    We have determined that listing the polar bear as a threatened 
species under the Act is appropriate, based on our evaluation of the 
actual and projected effects of the five listing factors on the species 
and its habitat. While polar bears are currently distributed throughout 
their range, the best available scientific information, including new 
USGS studies relating status and trends to loss of sea ice habitat 
(Durner et al. 2007; Amstrup et al. 2007), indicates that the polar 
bear is not currently in danger of extinction throughout all or a 
significant portion of their range, but are likely to become so within 
the 45-year ``foreseeable future'' that has been established for this 
rule. This satisfies the definition of a threatened species under the 
Act; consequently listing the species as threatened is appropriate. For 
additional information on factors affecting, or projected to affect, 
polar bears, please see the ``Summary of Factors Affecting the Polar 
Bear'' section of this final rule.
    Comment 2: The perceived status of the Western Hudson Bay 
population is disputed because data are unreliable, earlier population 
estimates cannot be compared to current estimates, and factors other 
than climate change could contribute to declines in the Western Hudson 
Bay population.
    Our response: The Western Hudson Bay population is the most 
extensively studied polar bear population in the world. Long-term 
demographic and vital rate (e.g., survival and recruitment) data on 
this population exceed those available for any other polar bear 
population. Regehr et al. (2007a) used the most advanced analysis 
methods available to conduct population analyses of the Western Hudson 
Bay population. Trend data demonstrate a statistically-significant 
population decline over time with a substantial level of precision. The 
authors attributed the population decline to increased natural 
mortality associated with earlier sea ice breakup and to the continued 
harvest of approximately 40 polar bears per year. Other factors such as 
the effects of research, tourism harassment, density dependence, or 
shifts in distribution were not demonstrated to impact this population. 
Regehr et al. (2007a) indicated that overharvest did not cause the 
population decline; however, as the population declined, harvest rates 
could have contributed to further depressing the population. Additional 
information has been included in the ``Western Hudson Bay'' section of 
this final rule that provides additional details on these points.
    Comment 3: The apparent decline in the Southern Beaufort Sea 
population is not significantly different from the previous population 
estimate.
    Our response: The Southern Beaufort Sea and Western Hudson Bay 
populations are the two most studied polar bear populations. Regehr et 
al. (2006) found no statistically significant difference between the 
most recent and earlier population estimates for the Southern Beaufort 
Sea population due to the large confidence interval for the earlier 
population estimate, which caused the confidence intervals for both 
estimates to overlap. However, we note that the Southern Beaufort Sea 
population has already experienced decreases in cub survival, 
significant decreases in body weights for adult males, and reduced 
skull measurements (Regehr et al. 2006; Rode et al. 2007). Similar 
changes were documented in the Western Hudson Bay population before a 
statistically significant decline in that population was documented 
(Regehr et al. 2007a). The status of the Southern Beaufort Sea 
population was determined to be declining on the basis of declines in 
vital rates, reductions in polar bear habitat in this area, and 
declines in polar bear condition, factors noted by both the Canadian 
Polar Bear Technical Committee (PBTC 2007) and the IUCN Polar Bear 
Specialist Group (Aars et al. 2006).
    Comment 4: Population information from den surveys of the Chukchi 
Sea polar bear population is not sufficiently reliable to provide 
population estimates.
    Our response: We recognize that the population estimates from 
previous den and aerial surveys of the Chukchi Sea population 
(Chelintsev 1977; Derocher et al. 1998; Stishov 1991a, b; Stishov et 
al. 1991) are quite dated and have such wide confidence intervals that 
they are of limited value in determining population levels or trends 
for management purposes. What the best available information indicates 
is that, while the status of the Chukchi Sea population is thought to 
have increased following a reduction of hunting pressure in the United 
States, this

[[Page 28239]]

population is now thought to be declining due primarily to overharvest. 
Harvest levels for the past 10-15 years (150-200 bears per year), which 
includes the legal harvest in Alaska and an illegal harvest in 
Chukoktka, Russia, are probably unsustainable. This harvest level is 
close to or greater than the unsustainable harvest levels experienced 
prior to 1972 (when approximately 178 bears were taken per year). 
Furthermore, this population has also been subject to unprecedented 
summer/autumn sea ice recessions in recent years, resulting in a 
redistribution of more polar bears to terrestrial areas in some years. 
Please see additional discussion of this population in the ``Current 
Population Status and Trend'' section of this document.
    Comment 5: Interpretation of population declines is questionable 
due, in some cases, to the age of the data and in other cases the need 
for caution due to perceived biases in data collection.
    Our response: We used the best available scientific information in 
assessing population status, recognizing the limitations of some of the 
information. This final rule benefits from new information on several 
populations (Obbard et al. 2007; Stirling et al. 2007; Regehr et al. 
2007a, b) and additional analyses of the relationship between polar 
bear populations and sea ice habitat (Durner et al. 2007). New 
information on population status and trends is included in the 
``Current Population Status and Trend'' section of this rule.
    Comment 6: Polar bear health and fitness parameters do not provide 
reliable insights into population trends.
    Our response: We recognize there are limits associated with direct 
correlations between body condition and population dynamics; however 
changes in body condition have been shown to affect reproduction and 
survival, which in turn can have population level effects. For example, 
the survival of polar bear cubs-of-the-year has been directly linked to 
their weight and the weight of their mothers, with lower weights 
resulting in reduced survival (Derocher and Stirling 1996; Stirling et 
al. 1999). Changes in body condition indices were documented in the 
Western Hudson Bay population before a statistically significant 
decline in that population was documented (Regehr et al. 2007a). Thus, 
changes in these indices serve as an ``early warning'' that may signal 
imminent population declines. New information from Rode et al. (2007) 
on the relationship between polar bear body condition indices and sea 
ice cover is also included in the ``Effects of Sea Ice Habitat Change 
on Polar Bears'' section of this final rule.
    Comment 7: Polar bears have survived previous warming events and 
therefore can adapt to current climate changes.
    Our response: We have addressed this issue by adding two sections 
to the final rule entitled ``Adaptation'' and ``Previous Warming 
Periods and Polar Bears'' under ``Summary of Factors Affecting the 
Polar Bear.'' To summarize these sections, we find that the long 
generation time of polar bears and the known physiological and physical 
characteristics of polar bears significantly constrain their ability to 
adapt through behavioral modification or natural selection to the 
unprecedentedly rapid loss of sea ice habitat that is occurring and is 
projected to continue throughout the species' range. Derocher et al. 
(2004, p. 163, 172) suggest that this rate of change will limit the 
ability of polar bears to respond and survive in large numbers. In 
addition, polar bears today experience multiple stressors (e.g., 
harvest, contaminants, oil and gas development, and additional 
interactions with humans) that were not present during historical 
warming periods. Thus, both the cumulative effects of multiple 
stressors and the rapid rate of climate change today create a unique 
and unprecedented challenge for present-day polar bears in comparison 
to historical warming events. See also above response to Comment PR4.
    Comment 8: Polar bears will adapt and alternative food sources will 
provide nutrition in the future. There are many food resources that 
polar bears could exploit as alternate food sources.
    Our response: New prey species could become available to polar 
bears in some parts of their range as climate change affects prey 
species distributions. However, polar bears are uniquely adapted to 
hunting on ice and need relatively large, stable seal populations to 
survive (Stirling and [Oslash]ritsland 1995). The best available 
evidence indicates that ice-dependent seals (also called ``ice seals'') 
are the only species that would be accessible in sufficient abundance 
to meet the high energetic requirements of polar bears. Polar bears are 
not adapted to hunt in open water, therefore, predation on pelagic 
(open-ocean) seals, walruses, and whales, is not likely due to the 
energetic effort needed to catch them in an open-water environment. 
Other ice-associated seals, such as harp or hooded seals, may expand 
their ranges and provide a near-term source of supplemental nutrition 
in some areas. Over the long term, however, extensive periods of open 
water may ultimately stress seals as sea ice (summer feeding habitat) 
retreats further north from southern rookeries. We found no new 
evidence suggesting that seal species with expanding ranges will be 
able to compensate for the nutritional loss of ringed seals throughout 
the polar bear's current range. Terrestrial food sources (e.g., animal 
carcasses, birds, musk oxen, vegetation) are not likely to be reliably 
available in sufficient amounts to provide the caloric value necessary 
to sustain polar bears. For additional information on this subject, 
please see the expanded discussion of ``Adaptation'' under ``Summary of 
Factors Affecting the Polar Bear.''
    Comment 9: Commenters expressed a variety of opinions on the 
determination of ``foreseeable future'' for the polar bear, suggesting 
factors such as the number and length of generations as well as the 
timeframe over which the threat can be analyzed be used to identify an 
appropriate timeframe.
    Our response: ``Foreseeable future'' for purposes of listing under 
the Act is determined on the basis of the best available scientific 
data. In this rule, it is based on the timeframe over which the best 
available scientific data allow us to reliably assess the effect of 
threats--principally sea ice loss--on the polar bear, and is supported 
by species-specific factors, including the species' life history 
characteristics (generation time) and population dynamics. The 
timeframe over which the best available scientific data allow us to 
reliably assess the effect of threats on the species is the critical 
component for determining the foreseeable future. In the case of the 
polar bear, the key threat is loss of sea ice, the species' primary 
habitat. Available information, including results of the IPCC AR4, 
indicates that climate change projections over the next 40-50 years are 
more reliable than projections over the next 80-90 years. On the basis 
of our analysis, as reinforced by conclusions of the IPCC AR4, we have 
determined that climate changes projected within the next 40-50 years 
are more reliable than projections for the second half of the 
21stcentury, for a number of reasons (see section on ``Projected 
Changes in Arctic Sea Ice'' for a detailed explanation). For this final 
rule, we have also identified three polar bear generations (adapted 
from the IUCN Red List criteria) or 45 years as an appropriate 
timeframe over which to assess the effects of threats on polar bear 
populations. This timeframe is long enough to take into account multi-
generational population dynamics, natural variation inherent with 
populations, environmental and habitat

[[Page 28240]]

changes, and the capacity for ecological adaptation (Schliebe et al. 
2006a). The 45-year timeframe coincides with the timeframe within which 
climate model projections are most reliable. This final rule provides a 
detailed explanation of the rationale for selecting 45 years as the 
foreseeable future, including its relationship to observed and 
projected changes in sea ice habitat (as well as the precision and 
certainty of the projected changes) and polar bear life history and 
population dynamics. Therefore, this period of time is supported by 
species-specific aspects of polar bears and the time frame of projected 
habitat loss with the greatest reliability.
    One commenter erroneously identified Congressional intent to limit 
foreseeable future to 10 years. We reviewed the particular document 
provided by the commenter-a Congressional Question & Answer response, 
dated September 26, 1972, which was provided by the U.S. Department of 
Commerce's National Oceanic and Atmospheric Administration's Deputy 
Administrator Pollock. Rather than expressing Congressional intent, 
this correspondence reflects the Commerce Department's perspective at 
that time about foreseeable future and not Congressional intent. 
Furthermore, Mr. Pollock's generic observations in 1972 are not 
relevant to the best scientific data available regarding the status of 
the polar bear, which has been recognized by leading polar bear 
biologists as having a high degree of reliability out to 2050.

Issue 2: Changes in Environmental Conditions

    Comment 10: An increase in landfast ice will result in increased 
seal productivity and, therefore, increased feeding opportunities for 
polar bears.
    Our response: We agree that future feeding opportunities for polar 
bears will in part relate to how climate change affects landfast ice 
because of its importance as a platform for ringed seal lairs. As long 
as landfast ice is available, ringed seals probably will be available 
to polar bears. Research by Rosing-Asvid (2006) documented a strong 
increase in the number of polar bears harvested in Greenland during 
milder climatic periods when ringed seal habitat was reduced (less ice 
cover) and lair densities were higher because seals were concentrated; 
these two factors provide better spring hunting for polar bears. In 
contrast to periodic warming, however, climate models project continued 
loss of sea ice and changes in precipitation patterns in the Arctic. 
Seal lairs require sufficient snow cover for lair construction and 
maintenance, and snow cover of adequate quality that persists long 
enough to allow pups to wean prior to onset of the melt period. Several 
studies described in this final rule have linked declines in ringed 
seal survival and recruitment with climate change that has resulted in 
increased rain events (which has lead to increased predation on seals) 
and decreased snowfall. Therefore, while polar bears may initially 
respond favorably to a warming climate due to an increased ability to 
capture seals, future reductions in seal populations will ultimately 
lead to declines in polar bear populations. Additional information was 
added to the section ``Effects of Sea Ice Habitat Changes on Polar Bear 
Prey'' to clarify this point.
    Comment 11: Polar bears will have increased hunting opportunities 
as the amount of marginal, unconsolidated sea ice increases.
    Our response: Marginal ice occurs at the edge of the polar basin 
pack ice; ice is considered unconsolidated when concentrations decline 
to less than 50 percent. The ability of polar bears to catch a 
sufficient number of seals in marginal sea ice will depend upon both 
the characteristics of the sea ice and the abundance of and access to 
prey. Loss of sea ice cover will reduce seal numbers and accessibility 
to polar bears, as discussed in ``Reduced prey availability'' section 
of this final rule. Even if ringed seals maintained their current 
population levels, which is unlikely, Harwood and Stirling (2000) 
suggest that ringed seals would remain near-shore in open water during 
summer ice recession, thereby limiting polar bear access to them. 
Benthic (ocean bottom) feeders, such as bearded seals and walruses, may 
also decrease in abundance and/or accessibility as ice recedes farther 
away from shallow continental shelf waters. Increased open water and 
reduced sea ice concentrations will provide seals with additional 
escape routes, diminish the need to maintain breathing holes, and serve 
to make their location less predictable and less accessible to polar 
bears, resulting in lowered hunting success. Polar bears would also 
incur higher energetic costs from additional movements required for 
hunting in or swimming through marginal, unconsolidated sea ice. 
Additional information from Derocher et al. (2004) was added to the 
section ``Effects of Sea Ice Habitat Changes on Polar Bear Prey'' to 
clarify this point.
    Comment 12: Polar bears will benefit from increased marine 
productivity as ocean waters warm farther north.
    Our response: If marine productivity in the Arctic increases, polar 
bears may benefit from increased seal productivity initially, provided 
that sea ice habitat remains available. As previously mentioned, polar 
bears need sea ice as a platform for hunting. Evidence from Western 
Hudson Bay, Southern Hudson Bay, and Southern Beaufort Sea populations 
indicates that reductions in polar bear body condition in these 
populations are the result of reductions in sea ice. Additional new 
information on the relationship between body condition, population 
parameters, and sea ice habitat for the Southern Beaufort Sea 
population (Rode et al. 2007) has been incorporated into the section on 
effects of sea ice change on polar bears.
    The extent to which marine productivity increases may benefit polar 
bears will be influenced, in part, by ringed seals' access to prey. 
Arctic cod (Boreogadus saida), which are the dominant prey item in many 
areas, depend on sea ice cover for protection from predators (Gaston et 
al. 2003). In western Hudson Bay, Gaston et al. (2003) detected Arctic 
cod declines during periods of reduced sea ice habitat. Should Arctic 
cod abundance decline in other areas, we do not know whether ringed 
seals will be able to switch to other pelagic prey or whether alternate 
food sources will be adequate to replace the reductions in cod.
    Comment 13: Sufficient habitat will remain in the Canadian Arctic 
and polar region to support polar bears for the next 40-50 years; 
therefore, listing is not necessary.
    Our response: Both the percentage of sea ice habitat and the 
quality of that habitat will be significantly reduced from historic 
levels over the next 40-50 years (Meehl et al. 2007; Durner et al. 
2007; IPCC 2007). New information on the extent and magnitude of sea 
ice loss is included previously in the section entitled ``Observed 
Changes in Arctic Sea Ice'' of this rule. Reductions in the area, 
timing, extent, and types of sea ice,among other effects, are expected 
to increase the energetic costs of movement and hunting to polar bears, 
reduce access to prey, and reduce access to denning areas. The ultimate 
effect of these impacts are likely to result in reductions in 
reproduction and survival, and corresponding decreases in population 
numbers. We agree that receding sea ice may affect archipelagic polar 
bear populations later than populations inhabiting the polar basin, 
because seasonal ice is projected to remain present longer in the 
archipelago than in other areas of the polar bear's range. The high 
Arctic archipelago is limited however, in its ability to sustain

[[Page 28241]]

a large number of polar bears because: (1) changes in the extent of ice 
and precipitation patterns are already occurring in the region; (2) the 
area is characterized by lower prey productivity (e.g., lower seal 
densities); and (3) polar bears moving into this area would increase 
competition among bears and ultimately affect polar bear survival. In 
addition, a small, higher-density population of polar bears in the 
Canadian Arctic would be subject to increased vulnerability to 
perturbations such as disease or accidental oil discharge from vessels. 
Because of the habitat changes anticipated in the next 40-50 years, and 
the corresponding reductions in reproduction and survival, and, 
ultimately, population numbers, we have determined that the polar bear 
is likely to be in danger of extinction throughout all or a significant 
portion of its range by 2050.

Issue 3: Anthropogenic Effects

    Comment 14: Disturbance from and cumulative effects of oil and gas 
activities in the Arctic are underestimated or incompletely addressed.
    Our response: Oil and gas activities will likely continue in the 
future in the Arctic. Additional, updated information has been included 
in the section ``Oil and Gas Exploration, Development, and Production'' 
in Factor A. We acknowledge that disturbance from oil and gas 
activities can be direct or indirect and may, if not subject to 
appropriate mitigation measures, displace bears or their primary prey 
(ringed and bearded seals). Such disturbance may be critical for 
denning polar bears, who may abandon established dens before cubs are 
ready to leave due to direct disturbance. We note that incidental take 
of polar bears due to oil and gas activities in Alaska are evaluated 
and regulated under the MMPA (Sec. 101a(5)A) and incidental take 
regulations are in place based on an overall negligible effect finding. 
Standard and site specific mitigation measures are prescribed by the 
Service and implemented by the industry (see detailed discussion in the 
section ``Marine Mammal Protection Act of 1972, as amended'' under 
Factor D).
    Indirect and cumulative effects of the myriad of activities 
associated with major oil and gas developments can be a concern 
regionally. However, the effects of oil and gas activities, such as oil 
spills, are generally associated with low probabilities of occurrence, 
and are generally localized in nature, We acknowledge that the sum 
total of documented impacts from these activities in the past have been 
minimal (see discussion in the ``Oil and Gas Exploration, Development, 
and Production'' section). Therefore, we do not believe that we have 
underestimated or incompletely addressed disturbance from or cumulative 
effects of oil and gas activities on polar bears, and have accurately 
portrayed the effect of oil and gas activities on the status of the 
species within the foreseeable future.
    Comment 15: The potential effects of oil spills on polar bears are 
underestimated, particularly given the technical limitations of 
cleaning up an oil spill in broken ice.
    Our response: We do not wish to minimize our concern for oil spills 
in the Arctic marine environment. We agree that the effects of a large 
volume oil spill to polar bears could be significant within the 
specific area of occurrence, but we believe that the probability of 
such a spill in Alaska is generally very low. At a regional level we 
have concerns over the high oil spill probabilities in the Chukchi Sea 
under hypothetical future development scenarios (Minerals Management 
Service (MMS) 2007). An oil spill in this area could have significant 
consequences to the Chukchi Sea polar bear population (MMS 2007). 
However, under the MMPA, since 1991 the oil and gas industry in Alaska 
has sought and obtained incidental take authorization for take of small 
numbers of polar bears. Incidental take cannot be authorized under the 
MMPA unless the Service finds that any take that is likely to occur 
will have no more than a negligible impact on the species. Through this 
authorization process, the Service has consistently found that a large 
oil spill is unlikely to occur. The oil and gas industry has 
incorporated technological and response measures that minimize the risk 
of an oil spill. A discussion of potential additive effects of 
mortalities associated with an oil spill in polar bear populations 
where harvest levels are close to the maximum sustained yield has been 
included in this final rule (see discussion in the ``Oil and Gas 
Exploration, Development, and Production'' section).
    Comment 16: The effects to polar bears from contaminants other than 
hydrocarbons are underestimated.
    Our response: We added information on the status of regulatory 
mechanisms pertaining to contaminants, which summarizes what is 
currently known about the potential threat of each class of 
contaminants with respect to current production and future trends in 
production and use. Based on a thorough review of the scientific 
information on their sources, pathways, geographical distribution, and 
biological effects, and as discussed in the analysis section of this 
final rule, we do not believe that contaminants currently threaten the 
polar bear.
    Comment 17: Cumulative effects of threat factors on polar bear 
populations are important, and need a more indepth analysis than 
presented in the proposed rule.
    Our response: The best available information on the potential 
cumulative effects from oil and gas activities in Alaska to polar bears 
and their habitat was incorporated into the final rule (National 
Research Council (NRC) 2003). We also considered the cumulative effects 
of hunting, contaminants, increased shipping, increases in epizootic 
events, and inadequacy of existing regulatory mechanisms in our 
analyses. We have determined that there are no known regulatory 
mechanisms in place at the national or international level that 
directly and effectively address the primary threat to polar bears-the 
rangewide loss of sea ice habitat within the foreseeable future. We 
also acknowledge that there are some existing regulatory mechanisms to 
address anthropogenic causes of climate change, and these mechanisms 
are not expected to be effective in counteracting the worldwide growth 
of GHG emissions within the foreseeable future. In addition, we have 
determined that overutilization does not currently threaten the species 
throughout all or a significant portion of its range. However, harvest 
is likely exacerbating the effects of habitat loss in several 
populations. In addition, continued harvest and increased mortality 
from bear-human encounters or other forms of mortality may become a 
more significant threat factor in the future, particularly for 
populations experiencing nutritional stress or declining population 
numbers as a consequence of habitat change. We have found that the 
other factors, while not currently rising to a level that threatens the 
species, may become more significant in the future as populations face 
stresses from habitat loss. Modeling of potential effects on polar 
bears of various factors (Amstrup et al. 2007) identified loss of sea 
ice habitat as the dominant threat. Therefore, our analysis in this 
final rule has focused primarily on the ongoing and projected effects 
of sea ice habitat loss on polar bears within the foreseeable future.

Issue 4: Harvest

    Comment 18: Illegal taking of bears is a significant issue that 
needs additional management action.

[[Page 28242]]

    Our response: We recognize that illegal take has an impact on some 
polar bear populations, especially for the Chukchi Sea population and 
possibly for other populations in Russia. We also believe that a better 
assessment of the magnitude of illegal take in Russia is needed, and 
that illegal harvest must be considered when developing sustainable 
harvest limits. We also conclude that increased use of coastal habitat 
by polar bears could increase the impact of illegal hunting in Russia, 
by bringing bears into more frequent contact with humans. However, 
available scientific information indicates that poaching and illegal 
international trade in bear parts do not threaten the species 
throughout all or a significant portion of its range.
    Comment 19: The Service should not rely solely on the Bilateral 
Agreement to remedy illegal take in Russia. Listing under the Act is 
necessary to allow for continued legal subsistence hunting.
    Our response: As discussed in the ``Summary of Factors Affecting 
the Polar Bear'' section of this rule, we have found that harvest and 
poaching affect some polar bear populations, but those effects are not 
significant enough to threaten the species throughout all or a 
significant portion of its range. To the extent that poaching is 
affecting local populations in Russia, the Service believes that the 
best tool to address these threats is the Agreement between the United 
States of America and the Russian Federation on the Conservation and 
Management of the Alaska-Chukotka Polar Bear Population (Bilateral 
Agreement), which was developed and is supported by both government and 
Native entities and includes measures to reduce poaching. The 
Convention on International Trade in Endangered Species of Wild Fauna 
and Flora (CITES) would address attempted international trade of 
unlawfully taken polar bears (or parts), and the MMPA would address 
attempted import into the United States of unlawfully taken animals or 
their parts. Subsistence hunting by natives in the United States is 
exempt from prohibitions under both the MMPA and the Act. Subsistence 
harvest does not require action under the Act to ensure its 
continuation into the future.
    Comment 20: The Service should prohibit the importation into the 
United States of polar bear trophies taken in Canada, and should amend 
the MMPA to prohibit sport hunting of polar bears.
    Our response: The polar bear is currently listed in Appendix II of 
CITES. Section 9(c)(2) of the Act provides that the non-commercial 
import of threatened and Appendix-II species, including their parts, 
that were taken in compliance with CITES is not presumed to be in 
violation of the Act. Thus, an import permit would not ordinarily be 
required under the Act. We note that the MMPA does not allow sport 
hunting of polar bears within the United States. In addition, we note 
that, under the MMPA, the polar bear will be considered a ``depleted'' 
species on the effective date of this listing. As a depleted species, 
imports could only be authorized under the MMPA if the import enhanced 
the survival of the species or was for scientific research. Therefore, 
authorization for the import of sport-hunted trophies would no longer 
be available under section 104(c)(5) of the MMPA.
    Comment 21: The Service failed to consider the negative impacts of 
listing on the long-term management of polar bears developed in Canada 
that integrates subsistence harvest allocations with a token sport 
harvest.
    Our response: We acknowledge the important contribution to 
conservation from scientifically-based sustainable use programs. 
Significant benefits to polar bear management in Canada have accrued as 
a result of the 1994 amendments to the MMPA that allow U.S. citizens 
who legally sport-harvest a polar bear from an MMPA-approved population 
in Canada to bring their trophies back into the United States. These 
benefits include economic revenues to native hunters and communities; 
enhanced funding a support for research; a United States conservation 
fund derived from permit fees that is used primarily on the Chukchi Sea 
population; and increased local support of scientifically-based 
conservation programs. Without this program, there would be a loss of 
funds derived from import fees; loss of economic incentives that 
promote habitat protection and maintain sustainable harvest levels in 
Canada; and loss of research opportunities in Canada and Russia, which 
are funded through sport-hunting revenue. While we recognize these 
benefits, the Service must list a species when the best scientific and 
commercial information available shows that the species meets the 
definition of endangered or threatened. The effect of the listing, in 
this case an end to the import provision under Section 104(c)(5) of the 
MMPA, is not one of the listing factors. Furthermore, the benefits 
accrued to the species through the import program do not offset or 
reduce the overall threat to polar bears from loss of sea ice habitat.
    Comment 22: The Service should promulgate an exemption under 
section 4(d) of the Act that would allow importation of polar bear 
trophies.
    Our response: We recognize the role that polar bear sport harvest 
has played in the support of subsistence, economic, and cultural values 
in northern communities, and we have supported the program where 
scientific data have been available to ensure sustainable harvest. We 
again note that, under the MMPA, the polar bear will be considered a 
``depleted'' species on the effective date of this listing. The MMPA 
contains provisions that prevent the import of sport-hunted polar bear 
trophies from Canada once the species is designated as depleted. A 4(d) 
rule under the Act cannot affect existing requirements under the MMPA.
    Comment 23: The rights of Alaska Natives to take polar bears should 
be protected.
    Our response: We recognize the social and cultural importance of 
polar bears to coastal Alaska Native communities, and we anticipate 
continuing to work with the Alaska Native community in a co-management 
fashion to address subsistence-related issues. Section 101(b) of the 
MMPA already exempts take of polar bears by Native people for 
subsistence purposes as long as the take is not accomplished in a 
wasteful manner. Section 10(e) of the Act also provides an exemption 
for Alaska Natives that allows for taking as long as such taking is 
primarily for subsistence purposes and the taking is not accomplished 
in a wasteful manner. In addition, non-edible byproducts of species 
taken in accordance with the exemption, when made into authentic native 
articles of handicraft and clothing, may be transported, exchanged, or 
sold in interstate commerce. Since 1987, we have monitored the Alaska 
Native harvest of polar bears through our Marking, Tagging and 
Reporting program [50 CFR 18.23(f)]. The reported harvest of polar 
bears by Alaska Natives is 1,614 animals during this nearly 20-year 
period, of which 965 were taken from the Chukchi Sea population and 649 
were taken from the Southern Beaufort Sea population.
    Alaska Natives' harvest of polar bears from the Southern Beaufort 
and Chukchi Seas is not exclusive, since both of these populations are 
shared across international boundaries with Canada and Russia 
respectively, where indigenous populations in both countries also 
harvest animals. Since 1988, the Inuvialuit Game Council (IGC) (Canada) 
and the North Slope Borough (NSB) (Alaska) have implemented an 
Inuvialuit-Inupiat Polar Bear Management Agreement for harvest of polar 
bears in the Southern Beaufort

[[Page 28243]]

Sea. The focus of this agreement is to ensure that harvest of animals 
from this shared population is conducted in a sustainable manner. The 
Service works with the parties of this agreement, providing technical 
assistance and advice regarding, among other aspects, information on 
abundance estimates and sustainable harvest levels. We expect that 
future harvest levels may be adjusted as a result of discussions at the 
meeting between the IGC and NSB, held in February 2008.
    We do have concerns regarding the harvest levels of polar bears 
from the Chukchi Sea, where a combination of Alaska Native harvest and 
harvest occurring in Russia may be negatively affecting this 
population. However, implementation of the recently ratified 
``Agreement between the United States of America and the Russian 
Federation on the Conservation and Management of the Alaska-Chukotka 
Polar Bear Population'' (Bilateral Agreement), with its provisions for 
establishment of a shared and enforced quota system between the United 
States and Russia, should ensure that harvest from the Chukchi Sea 
population is sustainable.
    Comment 24: If the polar bear is listed, subsistence hunting should 
be given precedence over other forms of take.
    Our response: As noted above, Alaska Native harvest of polar bears 
for subsistence is currently exempt under both the MMPA and the Act. 
Sport hunting of polar bears is not allowed in the United States under 
the MMPA, and take for other purposes is tightly restricted. For polar 
bears, the other primary type of take is incidental harassment during 
otherwise lawful activities. The Service has issued incidental take 
regulations under the MMPA since 1991, and these regulations include a 
finding that such takings will not have an adverse impact on the 
availability of polar bears for subsistence uses. Thus, the needs of 
the Alaska Native community, who rely in part on the subsistence 
harvest of polar bears, are addressed by existing provisions under both 
the MMPA and the Act.

Issue 5: Climate Change

    Comment 25: The accuracy and completeness of future climate 
projections drawn from climate models are questionable due to the 
uncertainty or incompleteness of information used in the models.
    Our response: Important new climate change information is included 
in this final rule. The Working Group I Report of the IPCC AR4, 
published in early 2007, is a key part of the new information, and 
represents a collaborative effort among climate scientists from around 
the world with broad scientific consensus on the findings. In addition, 
a number of recent publications are used in the final rule to 
supplement and expand upon results presented in the AR4; these include 
Parkinson et al. (2006), Zhang and Walsh (2006), Arzel et al. (2006), 
Stroeve et al. (2007, pp. 1-5), Wang et al. (2007, pp. 1,093-1,107), 
Chapman and Walsh (2007), Overland and Wang (2007a, pp. 1-7), DeWeaver 
(2007), and others. Information from these publications has been 
incorporated into appropriate sections of this final rule.
    Atmosphere-ocean general circulation models (AOGCMs, also known as 
General Circulation Models (GCMs)) are used to provide a range of 
projections of future climate. GCMs have been consistently improved 
over the years, and the models used in the IPCC AR4 are significantly 
improved over those used in the IPCC TAR and the ACIA report. There is 
``considerable confidence that the GCMs used in the AR4 provide 
credible quantitative estimates of future climate change, particularly 
at continental scales and above'' (IPCC 2007, p. 591). This confidence 
comes from the foundation of the models in accepted physical principles 
and from their ability to reproduce observed features of current 
climate and past climate changes. Additional confidence comes from 
considering the results of suites of models (called ensembles) rather 
than the output of a single model. Confidence in model outcomes is 
higher for some climate variables (e.g., temperature) than for others 
(e.g., precipitation).
    Despite improvements in GCMs in the last several years, these 
models still have difficulties with certain predictive capabilities. 
These difficulties are more pronounced at smaller spatial scales and 
longer time scales. Model accuracy is limited by important small-scale 
processes that cannot be represented explicitly in models and so must 
be included in approximate form as they interact with larger-scale 
features. This is partly due to limitations in computing power, but 
also results from limitations in scientific understanding or in the 
availability of detailed observations of some physical processes. 
Consequently, models continue to display a range of outcomes in 
response to specified initial conditions and forcing scenarios. Despite 
such uncertainties, all models predict substantial climate warming 
under GHG increases, and the magnitude of warming is consistent with 
independent estimates derived from observed climate changes and past 
climate reconstructions (IPCC 2007, p. 761; Overland and Wang 2007a, 
pp. 1-7; Stroeve et al. 2007, pp. 1-5).
    We also note the caveat, expressed by many climate modelers and 
summarized by DeWeaver (2007), that, even if global climate models 
perfectly represent all climate system physics and dynamics, inherent 
climate variability would still limit the ability to issue accurate 
forecasts (predictions) of climate change, particularly at regional and 
local geographical scales and longer time scales. A forecast is a more-
precise prediction of what will happen and when, while a projection is 
less precise, especially in terms of the timing of events. For example, 
it is difficult to accurately forecast the exact year that seasonal sea 
ice will disappear, but it is possible to project that sea ice will 
disappear within a 10-20 year window, especially if that projection is 
based on an ensemble of modeling results (i.e., results from several 
models averaged together). It is simply not possible to engineer all 
uncertainty out of climate models, such that accurate forecasts are 
possible. Climate scientists expend considerable energy in trying to 
understand and interpret that uncertainty. The section in this rule 
entitled ``Uncertainty in Climate Models'' discusses uncertainty in 
climate models in greater depth than is presented here.
    In summary, confidence in GCMs comes from their physical basis and 
their ability to represent observed climate and past climate changes. 
Models have proven to be extremely important tools for simulating and 
understanding climate and climate change, and we find that they provide 
credible quantitative estimates of future climate change, particularly 
at larger geographical scales.
    Comment 26: Commenters provided a number of regional examples to 
contradict the major conclusions regarding climate change.
    Our response: As noted in our response to Comment 25, GCMs are less 
accurate in projecting climate change over finer geographic scales, 
such as the variability noted for some regions in the Arctic, than they 
are for addressing global or continental-level climate change. Climate 
change projections for the Barents Sea are difficult, for example, 
because regional physics includes both local winds and local currents. 
Cyclic processes, such as the North Atlantic Oscillation (NAO), can 
also drive regional variability. We agree with one commenter that the 
NAO is particularly strong for Greenland (Chylek et al. 2006). However, 
the natural variability associated with this

[[Page 28244]]

phenomenon simply suggests that the future will also have large 
variability, but does not negate overall climate trends, because the 
basic physics of climate processes, including sea ice albedo feedback, 
are modeled in all major sectors of the Arctic Basin. The increased 
understanding of the basic physics related to climate processes and the 
inclusion of these parameters in current climate models, such as those 
used in the IPCC AR4, present a more complete, comprehensive, and 
accurate view of range-wide climate change than earlier models.
    Comment 27: Other models should be used in the analysis of 
forecasted environmental and population changes including population 
viability assessment and precipitation models.
    Our response: The Service has not relied upon the published results 
or use of a single climate model or single scenario in its analyses. 
Instead we have considered a variety of information derived from 
numerous climate model outputs. These include modeled changes in 
temperature, sea ice, snow cover, precipitation, freeze-up and breakup 
dates, and other environmental variables. The recent report of the IPCC 
AR4 provides a discussion of the climate models used, and why and how 
they resulted in improved analyses of climatic variable and future 
projections. Not only have the models themselves been improved, but 
many advances have been made in terms of how the model results were 
used. The AR4 utilized multiple results from single models (called 
multi-member ensembles) to, for example, test the sensitivity of 
response to initial conditions, as well as averaged results from 
multiple models (called multi-model ensembles). These two different 
types of ensembles allow more robust evaluation of the range of model 
results and more quantitative comparisons of model results against 
observed trends in a variety of parameters (e.g., sea ice extent, 
surface air temperature), and provide new information on simulated 
statistical variability. This final rule benefits from specific 
analyses of uncertainty associated with model prediction of Arctic sea 
ice decline (DeWeaver 2007; Overland and Wang 2007a, pp. 1-7), and 
identification of those models that best simulated observed changes in 
Arctic sea ice.
    We also updated this final rule with information on recently 
completed population models (e.g., Hunter et al. 2007), habitat values 
and use models (Durner et al. 2007), and population projection models 
(Amstrup et al. 2007), which can be found in the ``Current Population 
Status and Trend'' section.
    Comment 28: Future emission scenarios are unreliable or incomplete 
and use speculative carbon emission scenarios that inaccurately portray 
future levels.
    Our response: Emissions scenarios used in climate modeling were 
developed by the IPCC and published in its Special Report on Emissions 
Scenarios in 2000. These emissions scenarios are representations of 
future levels of GHGs based on assumptions about plausible demographic, 
socioeconomic, and technological changes. The most recent, 
comprehensive climate projections in the IPCC AR4 used scenarios that 
represent a range of future emissions: low, medium, and high. The 
majority of models used a ``medium'' or ``middle-of-the-road'' scenario 
due to the limited computational resources for multi-model simulations 
using GCMs (IPCC 2007, p. 761). In addition, Zhang and Walsh (2006) use 
three emission scenarios representative of the suite of possibilities 
and DeWeaver (2007 p. 28), in subsequent analyses, used the A1B 
``business as usual'' scenario as a representative of the medium-range 
forcing scenario, and other scenarios were not considered due to time 
constraints. Similarly, our final analysis considered a range of 
potential outcomes, based in part on the range of emission scenarios. 
For additional details see the previous section, ``Projected Changes in 
Arctic Sea Ice.''
    We agree that emissions scenarios out to 2100 are less certain with 
regard to technology and economic growth than projections out to 2050. 
This is reflected in the larger confidence interval around the mean at 
2100 than at 2050 in graphs of these emissions scenarios (see Figure 
SPM-5 in IPCC 2007). However, GHG loading in the atmosphere has 
considerable lags in its response, so that what has already been 
emitted and what can be extrapolated to be emitted in the next 15-20 
years will have impacts out to 2050 and beyond (IPCC 2007, p. 749; J. 
Overland, NOAA, in litt. to the Service, 2007). This is reflected in 
the similarity of low, medium, and high SRES emissions scenarios out to 
about 2050 (see discussion of climate change under ``Factor A. Present 
or Threatened Destruction, Modification, or Curtailment of the Species' 
Habitat or Range''). Thus, the uncertainty associated with emissions is 
lower for the foreseeable future timeframe (45 years) for the polar 
bear listing than longer timeframes.
    Comment 29: Atmospheric CO2 is an indicator of global 
warming and not a major contributor.
    Our response: Carbon dioxide (CO2) is one of four 
principal anthropogenically-generated GHGs, the others being nitrous 
oxide (N2O), methane (CH4), and halocarbons (IPCC 
2007, p. 135). The IPCC AR4 considers CO2 to be the most 
important anthropogenic GHG (IPCC 2007, p. 136). The GHGs affect 
climate by altering incoming solar radiation and out-going thermal 
radiation, and thus altering the energy balance of the Earth-atmosphere 
system. Since the start of the industrial era, the effect of increased 
GHG concentrations in the atmosphere has been widespread warming of the 
climate, with disproportionate warming in large areas of the Arctic 
(IPCC 2007, p. 37). A net result of this warming is a loss of sea ice, 
with notable reductions in Arctic sea ice.
    Comment 30: Atmospheric CO2 levels are not greater today 
than during pre-industrial time.
    Our response: The best available scientific evidence unequivocally 
contradicts this comment. Atmospheric concentration of carbon dioxide 
(CO2) has increased significantly during the post-industrial 
period based on information from polar ice core records dating back at 
least 650,000 years. The recent rate of change is also dramatic and 
unprecedented, with the increase documented in the last 20 years 
exceeding any increase documented over a thousand-year period in the 
historic record (IPCC AR4, p. 115). Specifically, the concentration of 
atmospheric CO2 has increased from a pre-industrial value of 
about 280 ppm to 379 ppm in 2005, with an annual growth rate larger 
during the last 10 years than it has been since continuous direct 
atmospheric measurements began in 1960. These increases are largely due 
to global increases in GHG emissions and land use changes such as 
deforestation and burning (IPCC 2007, pp. 25-26).
    Comment 31: Consider the impacts of black carbon (soot) due to 
increased shipping as a factor affecting the increase in the melting of 
the sea ice.
    Our response: We recognize that there are large uncertainties about 
the contribution of soot to snow melt patterns. A general understanding 
is that soot (from black carbon aerosols) deposited on snow reduces the 
surface albedo with a resulting increase in snow melt process (IPCC 
2007, p. 30). Estimates of the amount of effect from all sources of 
soot have wide variance, and the exact contribution from increased 
shipping cannot be determined at this time.
    Comment 32: Climate models do not adequately address naturally 
occurring phenomena.

[[Page 28245]]

    Our response: In IPCC AR4 simulations, models were run with natural 
and anthropogenic (i.e., GHG) forcing for the period of the 
observational record (i.e., the 20th century). Results from different 
models and different runs of the same model can be used to simulate the 
observed range of natural variability in the 20th century (such as warm 
in 1930s and cool in the 1960s). Only when GHG forcing is added to 
natural variability, however, do the models simulate the warming 
observed in the later portion of the 20th century (Wang et al. 2007). 
This is shown for the Arctic by Wang et al. (2007, pp. 1,093-1,107). 
This separation is shown graphically in Figure SPM-4 of the IPCC AR4 
(shown below, reproduced from IPCC 2007 with permission); note the 
separation of the model results with and without greenhouse gases at 
the end of the 20th century for different regions. Thus comparison of 
forced CO2 trends and natural variability were central to 
the IPCC AR4 analyses, and are discussed in this final rule.
[GRAPHIC] [TIFF OMITTED] TR15MY08.009

    Analyses of paleoclimate data increase confidence in the role of 
external influences on climate. The GCMs used to predict future climate 
provide insight into past climatic conditions of the Last Glacial 
Maximum and the mid-Holocene. While many aspects of these past climates 
are still uncertain, climate models reproduce key features by using 
boundary conditions and natural forcing factors for those periods. The 
IPCC AR4 concluded that a substantial fraction of the reconstructed 
Northern Hemisphere inter-decadal temperature variability of the seven 
centuries prior to 1950 is very likely attributable to natural external 
forcing, and it is likely that anthropogenic forcing contributed to the 
early 20th-century warming evident in these records (IPCC 2007).
    Comment 33: Current climate patterns are part of the natural cycle 
and reflect natural variability.
    Our response: Considered on a global scale, climate is subject to 
an inherent degree of natural variability. However, evidence of human 
influence on the recent evolution of climate has accumulated steadily 
during the past two decades. The IPCC AR4 has concluded that (1) most 
of the observed increase in globally-averaged temperatures since the 
mid-20th century is very likely due to the observed increase in 
anthropogenic GHG concentrations; and (2) it is likely there has been 
significant anthropogenic warming over the past 50 years averaged over 
each continent (except Antarctica) (IPCC 2007, p. 60).

[[Page 28246]]

    Comment 34: There was a selective use of climate change information 
in the proposed rule, and the analysis ignored climate information 
about areas that are cooling.
    Our response: We acknowledge that climate change and its effects on 
various physical processes (such as ice formation and advection, 
snowfall, precipitation) vary spatially and temporally, and that this 
has been considered in our analysis. While GCMs are more effective in 
characterizing climate change on larger scales, we have considered that 
the changes and effects are not uniform in their timing, location, or 
magnitude such as identified by Laidre et al. (2005) and Zhang and 
Walsh (2006). Indeed, the region southwest of Greenland does not show 
substantial warming by 2050 according to some climate projections. 
However, most polar bear habitat regions do show the substantial loss 
of sea ice by 2040-2050. While regional differences in climate change 
exist, this will not change the effect of climatic warming anticipated 
to occur within the foreseeable future within the range of polar bears. 
Updated information on regional climate variability has been added to 
the section ``Overview of Arctic Sea Ice Change.''
    Comment 35: The world will be cooler by 2030 based on sunspot cycle 
phenomena, which is the most important determinant of global warming 
(e.g., Soon et al. 2005; Jiang et al. 2005).
    Our response: The issue of solar influences, including sunspots, in 
climate change has been considered by many climate scientists, and 
there is considerable disagreement about any large magnitude of solar 
influences and their importance (Bertrand et al. 2002; IPCC 2007). The 
most current synthesis of the IPCC (AR4, p. 30) describes a well 
established, 11-year cycle with no significant long term trend based on 
new data obtained through significantly improved measurements over a 
28-year period. Solar influence is considered in the IPCC models and is 
a small effect relative to volcanoes and CO2 forcing in the 
later half of the 20th century. While more complex solar influences due 
to cosmic ray/ionosphere/cloud connections have been hypothesized, 
there is no clear demonstration of their having a large effect.
    Comment 36: The IPCC report fails to give proper weight to the 
geological context and relationship to climate change.
    Our response: Paleoclimatic events were analyzed in the IPCC AR4, 
which concluded that ``Confidence in the understanding of past climate 
change and changes in orbital forcing is strengthened by the improved 
ability of current models to simulate past climate conditions.'' Model 
results indicate that the Last Glacial Maximum (about 21,000 years ago) 
and the mid-Holocene (6,000 years ago) were different from the current 
climate not because of random variability, but because of altered 
seasonal and global forcing linked to known differences in the Earth's 
orbit. This additional information has been incorporated in this final 
rule.
    Comment 37: Movement of sea ice from the Arctic depends on the 
Aleutian Low, Arctic Oscillation (AO), North Atlantic Oscillation 
(NAO), and Pacific Decadal Oscillation (PDO) rather than GHG emissions.
    Our response: Sea ice is lost from the Arctic by a combination of 
dynamic and thermodynamic mechanisms. Not only is it lost by advection, 
but lost as a result of changes in surface air and water temperatures. 
Changes in surface air temperature are strongly influenced by warming 
linked to GHG emissions, while increases in water temperature are 
influenced by warming, the sea ice-albedo feedback mechanism, and the 
influx of warmer subpolar waters (largely in the North Atlantic) 
(Serreze et al. 2007). Recent studies (IPCC 2007, p. 355; Stroeve et al 
2007; Overland and Wang 2007a, pp. 1-7) recognize considerable natural 
variability in the pattern of sea ice motion relative to the AO, NAO, 
and PDO, which will continue into the 21st century. However, the 
distribution of sea ice thickness is a factor in the amount of sea ice 
that is advected from the Arctic, and this distribution is 
significantly affected by surface air and water temperature.
    Comment 38: Changes in the sea ice extent vary throughout the 
Arctic but overall extent has not changed in past 50 years.
    Our response: All observational data collected since the 1950s 
points to a decline in both Arctic sea ice extent and area, as well as 
an increasing rate of decline over the past decade. While sea ice cover 
does have a component of natural variability, such variability does not 
account for the influence that increased air and water temperatures 
will have on sea ice in the future. The pattern of natural variability 
will continue, but will be in conjunction with the overall declining 
trend due to warming, and the combination could result in abrupt 
declines in sea ice cover faster than would be expected from GHG 
warming alone.
    Comment 39: Evidence that does not support climate change was not 
included in the analyses.
    Our response: We recognize that there are scientific differences of 
opinion on many aspects of climate change, including the role of 
natural variability in climate and also the uncertainties involved with 
both the observational record and climate change projections based on 
GCMs. We have reviewed a wide range of documents on climate change, 
including some that espouse the view that the Earth is experiencing 
natural cycles rather than directional climate change (e.g., Damon and 
Laut 2004; Foukal et al. 2006). We have consistently relied on 
synthesis documents (e.g., IPCC AR4; ACIA) that present the consensus 
view of a very large number of experts on climate change from around 
the world. We have found that these synthesis reports, as well as the 
scientific papers used in those reports or resulting from those 
reports, represent the best available scientific information we can use 
to inform our decision and have relied upon them and provided citation 
within our analysis.
    Comment 40: Current conditions, based on past variation in Arctic 
sea ice and air temperatures, are by no means unprecedented and 
consequently the survival of polar bears and other marine mammals is 
not of concern.
    Our response: We acknowledge that previous warming events (e.g., 
the Last Interglacial period (LIG), Holocene Thermal Maximum (HTM)) 
likely affected polar bears to some unknown degree. The fact that polar 
bears survived these events does not mean that they are not being 
affected by current sea ice and temperature changes. Indeed, the best 
available scientific information indicates that several populations are 
currently being negatively affected, and projections indicate that all 
populations will be negatively affected within the foreseeable future, 
such that the species will be in danger of extinction throughout all or 
a significant portion of its range within that timeframe. We have 
included additional information regarding previous warming events and 
an explanation of potential for polar bears to adapt in the section 
``Effects of Sea Ice Habitat Changes on Polar Bear Prey.''
    We agree that there is considerable natural variability and region-
to-region differences in sea ice cover as documented by numerous 
journal articles and other references (Comiso 2001; Omstedt and Chen 
2001; Jevrejeva 2001; Polyakov et al. 2003; Laidre and Heide-Jorgensen 
2005). However, current conditions are unprecedented (IPCC 2007, p. 
24). Climate scientists agree that atmospheric concentrations of

[[Page 28247]]

CO2 and CH4 far exceed the natural range over the 
last 650,000 years. The rate of growth in atmospheric concentration of 
GHGs is considered unprecedented (IPCC 2007, p. 24). The recent 
publication by Canadell et al. (2007) indicates that the growth rate of 
atmospheric CO2 is increasing rapidly. An increasing 
CO2 concentration is consistent with results of climate-
carbon cycle models, but the magnitude of the observed atmospheric 
CO2 concentration appears larger than that estimated by 
models. The authors suggest that these changes characterize a carbon 
cycle that is generating stronger-than-expected and sooner-than-
expected climate forcing. What also is unprecedented is the potential 
for continued sea ice loss into the 21st century based on the physics 
of continued warming due to external forcing, and the accelerated 
impact of the ice albedo feedback as more open water areas open. 
Consideration of future loss of sea ice does not depend only on the sea 
ice observational record by itself. However, current sea ice loss, 
which now averages about 10 percent per decade over the last 25 years, 
plus the extreme loss of summer sea ice in 2007, is a warning sign that 
significant changes are underway, and data indicate that these extremes 
will continue into the foreseeable future.

Issue 6: Regulatory Mechanisms

    Comment 41: Treaties, agreements, and regulatory mechanisms for 
population management of polar bears exist and are effective; thus 
there is no need to list the species under the Act.
    Our response: The Service recognizes that existing polar bear 
management regulatory mechanisms currently in place have been effective 
tools in the conservation of the species; the ability of the species as 
a whole to increase in numbers from low populations, as discussed in 
our response to Comment 1, associated with over-hunting pressures of 
the mid 20th century attest to such effectiveness. As discussed under 
Factor D, there is a lack of regulatory mechanisms to address the loss 
of habitat due to reductions in sea ice. We acknowledge that progress 
is being made, and may continue to be made, to address climate change 
resulting from human activity; however, the current and expected impact 
to polar bear habitat indicates that in the foreseeable future, as 
defined in this rule, such efforts will not ameliorate loss of polar 
bear habitat or numbers of polar bears.
    Comment 42: The Service did not consider existing local, State, 
National, and International efforts to address climate change (e.g., 
the Kyoto Protocol or United Nations Framework Convention on Climate 
Change) and is incorrect in concluding that there are no known 
regulatory mechanisms effectively addressing reductions in sea ice 
habitat. Furthermore, the Service failed to consider the probability of 
a global response to growing demands to deal with global climate 
change.
    Our response: We have included discussion of domestic and 
international efforts to address climate change in the ``Inadequacy of 
Existing Regulatory Mechanisms'' (Factor D) section. While we note 
various efforts are ongoing, we conclude that such efforts have not yet 
proven to be effective at preventing loss of sea ice. The Service's 
``Policy for Evaluation of Conservation Efforts When Making Listing 
Decisions'' (68 FR 15100) provides guidance for analyzing future 
conservation efforts and requires that the Service only rely on efforts 
that we have found will be both implemented and effective. While we 
note that efforts are being made to address climate change, we are 
unaware of any programs currently being shown to effectively reduce 
loss of polar bear ice habitat at a local, regional, or Arctic-wide 
scale.
    Comment 43: The Service should evaluate the recent Supreme Court 
ruling that the U.S. Environmental Protection Agency (EPA) has the 
authority under the Clean Air Act to regulate GHGs.
    Our response: The Service recognizes the leading role the EPA plays 
in implementing the Clean Air Act. However, specific considerations 
regarding the recent Supreme Court decision are beyond the scope of 
this decision.
    Comment 44: The effort to list the polar bear is an inappropriate 
attempt to regulate GHG emissions. Any decision to limit GHG emissions 
should be debated in the open and not regulated through the ``back 
door'' by the Act.
    Our response: The Service was petitioned to evaluate the status of 
polar bears under the Act. In doing so, we evaluated the best 
scientific and commercial information available on present and 
foreseeable future status of polar bears and their habitat as required 
by the Act. The role of the Service is to determine the appropriate 
biological status of the polar bear and that is the scope of this rule. 
Some commenters to the proposed rule suggested that the Service should 
require other agencies (e.g., the EPA) to regulate emissions from all 
sources, including automobiles and power plants. The science, law, and 
mission of the Service do not lead to such action. Climate change is a 
worldwide issue. A direct causal link between the effects of a specific 
action and ``take'' of a listed species is well beyond the current 
level of scientific understanding (see additional discussion of this 
topic under the ``Available Conservation Measures'' section).
    Comment 45: Listing of the polar bear is more about the politics of 
global climate change than biology of polar bears.
    Our response: The Service was petitioned to list polar bears under 
the Act and we evaluated the best available scientific and commercial 
information available on threats to polar bears and their habitat as 
required by the Act. The role of the Service is to determine the 
appropriate status of the polar bear under the Act, and that is the 
scope of this rule.

Issue 7: Listing Justification

    Comment 46: Justification for listing is insufficient or limited to 
few populations, and thus range-wide listing is not warranted.
    Our response: This document contains a detailed evaluation of the 
changing sea ice environment and research findings that describe the 
effect of environmental change on the declining physical condition of 
polar bears, corresponding declines in vital rates, and declines in 
population abundance. We acknowledge that the timing, rate and 
magnitude of impacts will not be the same for all polar bear 
populations. However, the best available scientific information 
indicates that several populations are currently being negatively 
affected, and projections indicate that all populations will be 
negatively affected within the foreseeable future, such that the 
species will be in danger of extinction throughout all or a significant 
portion of its range within that timeframe.
    Since the proposed rule was published (72 FR 1064), the USGS 
completed additional analyses of population trajectories for the 
Southern Beaufort Sea population (Hunter et al. 2007), and updated 
population estimates for the Northern Beaufort Sea (Stirling et al. 
2007) and Southern Hudson Bay (Obbard et al. 2007) populations 
(summarized in the ``Background'' section of this final rule). The USGS 
also has conducted additional modeling of habitat resource selection in 
a declining sea ice environment (Durner et al. 2007), and an evaluation 
of the levels of uncertainty or likelihood of outcomes for a variety of 
climate models (DeWeaver 2007). Information from these recent USGS 
analyses is included

[[Page 28248]]

and cited within this rule and balanced with other published 
information evaluating current and projected polar bear status. In 
addition, since the publication of the proposed rule (72 FR 1064), the 
IPCC AR4 and numerous other publications related to climate change and 
modeled climate projections have become available in published form and 
are now included and cited within this rule.
    We considered whether listing particular Distinct Population 
Segments (DPSs) is warranted, but we could not identify any geographic 
areas or populations that would qualify as a DPS under our 1996 DPS 
Policy (61 FR 4722), because there are no population segments that 
satisfy the criteria of the DPS Policy.
    Finally, we analyzed the status of polar bears in portions of its 
range to determine if differential threat levels in those areas warrant 
a determination that the species is endangered rather than threatened 
in those areas. The overall direction and magnitude of threats to polar 
bears lead us to conclude that the species is threatened throughout its 
range, and that there are no significant portions of the range where 
the polar bear would be considered currently in danger of extinction.
    On the basis of all these analyses, we have concluded that the best 
available scientific information supports a determination that the 
species is threatened throughout all of its range.
    Comment 47: Traditional ecological knowledge (TEK) does not support 
the conclusion that polar bear populations are declining and negatively 
impacted by climate change.
    Our response: We acknowledge that TEK may provide a relevant source 
of information on the ecology of polar bears obtained through direct 
individual observations. We have expanded and incorporated additional 
discussion of TEK into our determination. Additionally, we have 
received and reviewed comments from individuals with TEK on both 
climate change and polar bears. While there may be disagreement among 
individuals on the impacts of climate change on polar bears, we believe 
there is general scientific consensus that sea ice environment is 
diminishing.
    Comment 48: Cannibalism, starvation, and drowning are naturally 
occurring events and should not be inferred as reasons for listing.
    Our response: We agree that cannibalism, starvation, and drowning 
occur in nature; however, we have not found that these are mortality 
factors that threaten the species throughout all or a significant 
portion of its range. Rather, we find that recent research findings 
have identified the unusual nature of some reported mortalities, and 
that these events serve as indicators of stressed populations. The 
occurrence and anecdotal observation of these events and potential 
relationship to sea ice changes is a current cause for concern. In the 
future, these events may take on greater significance, especially for 
populations that may be experiencing nutritional stress or related 
changes in their environment.
    Comment 49: The Service did not adequately consider polar bear use 
of marginal ice zones in the listing proposal.
    Our response: Due to the dynamic and cyclic nature of sea ice 
formation and retreat, marginal ice zones occur on an annual basis 
within the circumpolar area and indeed are important habitat for polar 
bears. The timing of occurrence, location, and persistence of these 
zones over time are important considerations because they serve as 
platforms for polar bears to access prey. Marginal ice zones that are 
associated with shallow and productive nearshore waters are of greatest 
importance, while marginal ice zones that occur over the deeper, less 
productive central Arctic basin are not believed to provide values 
equivalent to the areas nearshore. New information on polar bear 
habitat selection and use (Durner et al. 2007) is included in this 
rule's sections ``Polar Bear-Sea Ice Habitat Relationships'' and 
``Effects of Sea Ice Habitat Change on Polar Bears.''
    Comment 50: The effects of climate change on polar bears will vary 
among populations.
    Our response: We recognize that the effects of climate change will 
vary among polar bear populations, and have discussed those differences 
in detail in this final rule. We have determined that several 
populations are currently being negatively affected, and projections 
indicate that all populations will be negatively affected within the 
foreseeable future. Preliminary modeling analyses of future scenarios 
using a new approach (the Bayesian Network Model) describe four 
``ecoregions'' based on current and projected sea ice conditions 
(Amstrup et al. 2007); a discussion of these analyses is included in 
Factor A of the ``Summary of Factors Affecting the Species.'' 
Consistent with other projections, the preliminary model projects that 
southern populations with seasonal ice-free conditions and open Arctic 
Basin populations in areas of ``divergent'' sea ice will be affected 
earliest and to the greatest extent,while populations in the Canadian 
archipelago populations and populations in areas of ``convergent ``sea 
ice'' will be affected later and to a lesser extent. These model 
projections indicate that impacts will happen at different times and 
rates in different regions. On the basis of the best available 
scientific information derived from this preliminary model and other 
extensive background information, we conclude that the species is not 
currently in danger of extinction throughout all or a significant 
portion of its range, but is very likely to become so within the 
foreseeable future. We have not identified any areas or populations 
that would qualify as Distinct Population Segments under our 1996 DPS 
Policy, or any significant portions of the polar bear's range that 
would qualify for listing as endangered (see response to Comment 47).
    Comment 51: The 19 populations the Service has identified cannot be 
thought of as discrete or stationary geographic units, and polar bears 
should be considered as one Arctic population.
    Our response: We agree that the boundaries of the 19 populations 
are not static or stationary. Intensive scientific study of movement 
patterns and genetic analysis reinforces boundaries of some populations 
while confirming that overlap and mixing occur among others. Neither 
movement nor genetic information is intended to mean that the 
boundaries are absolute or stationary geographic units; instead, they 
most accurately represent discrete functional management units based on 
generalized patterns of use.
    Comment 52: The Service should evaluate the status of the polar 
bear in significant portions of the range or distinct population 
segments, due to regional differences in climate parameters, and 
therefore the response of polar bears.
    Our response: We analyzed the status of polar bears by population 
and region in the section ``Demographic Effects of Sea Ice Changes on 
Polar Bear'' and considered how threats may differ between areas. We 
recognize that the level, rate, and timing of threats will be uneven 
across the Arctic and, thus, that polar bear populations will be 
affected at different rates and magnitudes depending on where they 
occur. We find that, although habitat (i.e., sea ice) changes may occur 
at different rates, the direction of change is the same. Accepted 
climate models (IPCC AR4 2007; DeWeaver 2007), based on their ability 
to simulate present day ice patterns, all project a unidirectional loss 
of sea ice. Similarly, new analyses of polar bear habitat distribution 
in the polar basin projected over time (Durner et al. 2007) found that 
while the rate of

[[Page 28249]]

change in habitat varied between GCMs, all models projected habitat 
loss in the polar basin within the 45-year foreseeable future 
timeframe. Therefore, despite the regional variation in changes and 
response, we find that the primary threat (loss of habitat) is 
occurring and is projected to continue to occur throughout the Arctic. 
In addition, the USGS also examined how the effects of climate change 
will vary across time and space; their model projections also indicate 
that impacts will happen at different times and rates in different 
regions (Amstrup et al. 2007).
    Recognizing the differences in the timing, rate, and magnitude of 
threats, we evaluated whether there were any specific areas or 
populations that may be disproportionately threatened such that they 
currently meet the definition of an endangered species versus a 
threatened species. We first considered whether listing one or more 
Distinct Population Segments (DPS) as endangered may be warranted. We 
then considered whether there are any significant portions of the polar 
bear's range (SPR) where listing the species as endangered may be 
warranted. In evaluating current status of all populations and 
projected sea ice changes and polar bear population projections, we 
were unable to identify any distinct population segments or significant 
portions of the range of the polar bear where the species is currently 
in danger of extinction. Rather, we have concluded that the polar bear 
is likely to become an endangered species throughout its range within 
the foreseeable future. Thus, we find that threatened status throughout 
the range is currently the most appropriate listing under the Act.
    Comment 53: One commenter asserted that the best available 
scientific information indicates that polar bear populations in two 
ecoregions defined by Amstrup et al. (2007)--the Seasonal Ice ecoregion 
and the polar basin Divergent ecoregion--should be listed as 
endangered.
    Our response: We separately evaluated whether polar bear 
populations in these two ecoregions qualify for a different status than 
polar bears in the remainder of the species' range. We determined that 
while these polar bears are likely to become in danger of extinction 
within the foreseeable future, they are not currently in danger of 
extinction. See our analysis in the section ``Distinct Population 
Segment (DPS) and Significant Portion of the Range (SPR) Evaluation.''
    Comment 54: There is insufficient evidence to conclude that the 
polar bear will be threatened or extinct within three generations as no 
quantitative analysis or models of population numbers (or prey 
abundance) are offered.
    Our response: New information on population status and trends for 
the Southern Beaufort Sea (Hunter et al. 2007; Regehr et al. 2007b) and 
updated population estimates for the Northern Beaufort Sea (Stirling et 
al. 2007) and Southern Hudson Bay (Obbard et al. 2007) populations is 
included in this rule along with range-wide population projections 
based on polar bear ecological relationship to sea ice and to changes 
in sea ice over time (Amstrup et al. 2007). These studies, plus the 
IPCC AR4, and additional analyses of climate change published within 
the last year, have added substantially to the final rule. Taken 
together, the new information builds on previous analyses to provide 
sufficient evidence to demonstrate that: (1) polar bears are sea ice-
dependent species; (2) reductions in sea ice are occurring now and are 
very likely to continue to occur within the foreseeable future; (3) the 
linkage between reduced sea ice and population reductions has been 
established; (4) impacts on polar bear populations will vary in their 
timing and magnitude, but all populations will be affected within the 
foreseeable future; and (5) the rate and magnitude of the predicted 
changes in sea ice will make adaptation by polar bears unrealistic. On 
these bases, we have determined that the polar bear is not currently in 
danger of extinction throughout all or a significant portion of its 
range, but is likely to become so within the foreseeable future.
    Comment 55: Perceptions differ as to whether polar bear populations 
will decline with loss of sea ice habitat.
    Our response: Long-term data sets necessary to establish the 
linkage between population declines and climate change do not exist for 
all polar bear populations within the circumpolar Arctic. However, the 
best available scientific information indicates a link between polar 
bear vital rates or population declines and climate change. For two 
populations with extensive time series of data, Western Hudson Bay and 
Southern Beaufort Sea, either the population numbers or survival rates 
are declining and can be related to reductions in sea ice. In addition, 
scientific literature indicates that the Davis Strait, Baffin Bay, Foxe 
Basin, and the Eastern and Western Hudson Bay populations are expected 
to decline significantly in the foreseeable future based on reductions 
of sea ice projected in Holland et al. (2006, pp. 1-5). Additional 
population analyses (Regehr et al. 2007a, b; Hunter et al. 2007; Obbard 
et al. 2007) that further detail this relationship have been recently 
completed and are included in this final rule.
    Comment 56: Factors supporting listing are cumulative and thus are 
unlikely to be quickly reversed. Polar bears are likely to become 
endangered within one to two decades.
    Our response: We have concluded that habitat loss (Factor A) is the 
primary factor that threatens the polar bear throughout its range. We 
have also determined that there are no known regulatory mechanisms in 
place, and none that we are aware of that could be put in place, at the 
national or international level, that directly and effectively address 
the rangewide loss of sea ice habitat within the foreseeable future 
(Factor D). However, we have also concluded that other factors (e.g., 
overutilization) may interact with and exacerbate these primary threats 
(particularly habitat loss) within the 45-year foreseeable future.
    Polar bear populations are being affected by habitat loss now, and 
will continue to be affected within the foreseeable future. We do not 
believe that the species is currently endangered, but we believe it is 
likely that the species will become endangered during the foreseeable 
future given current and projected trends; see detailed discussion 
under Factor A in the section ``Demographic Effects of Sea Ice Changes 
on Polar Bear''. We intend to continue to evaluate the status of polar 
bears and will review and amend the status determination if conditions 
warrant. Through 5-year reviews and international circumpolar 
monitoring, we will closely track the status of the polar bear over 
time.
    Comment 57: Polar bears face unprecedented threats from climate 
change, environmental degradation, and hunting for subsistence and 
sport.
    Our response: We agree in large part as noted in detail within this 
final rule, but clarify that hunting for subsistence or sport does not 
currently threaten the species in all or a significant portion of its 
range, and where we have concerns regarding the harvest we are hopeful 
that existing or newly established regulatory processes, e.g., the 
recently adopted Bilateral Agreement, will be adequate to ensure that 
harvest levels are sustainable and can be adjusted as our knowledge of 
population status changes over time. Please see the ``Summary of 
Factors Affecting the Polar Bear'' for additional discussion of these 
issues.

[[Page 28250]]

Issue 8: Listing Process

    Comment 58: Listing the polar bear under the Act should be delayed 
until reassessment of the status of the species under Canada's Species 
at Risk Act (SARA) is completed.
    Our response: When making listing decisions, section 4 of the Act 
establishes firm deadlines that must be followed, and does not allow 
for an extension unless there is substantial scientific disagreement 
regarding the sufficiency or accuracy of relevant data. Section 4(b) 
directs the Secretary to take into account any efforts being made by 
any State or foreign nation to protect the species under consideration; 
however, the Act does not allow the Secretary to defer a listing 
decision pending the outcome of any such efforts. The status of the 
polar bear under Canada's SARA is discussed under Factor D.
    Comment 59: The Act was not designed to list species based on 
future status.
    Our response: We agree. We have determined that the polar bear's 
current status is that it is ``likely to become an endangered species 
within the foreseeable future throughout all or a significant portion 
of its range.'' This is the definition of a threatened species under 
the Act, and we are accordingly designating the species as threatened.
    Comment 60: Use of the IUCN Red Listing criteria for a listing 
determination under the Act is questionable, and should not be used.
    Our response: While we may consider the opinions and 
recommendations of other experts (e.g., IUCN), the determination as to 
whether a species meets the definition of threatened or endangered must 
be made by the Service, and must be based upon the criteria and 
standards in the Act. After reviewing the best available scientific and 
commercial information, we have determined that the polar bear is 
threatened throughout its range, based upon an assessment of threats 
according to section 4 of the Act. While some aspects of our 
determination may be in line with the IUCN Red List criteria (e.g., we 
used some Red List criteria for determination of generation time), we 
have not used the Red List criteria as a standard for our 
determination. Rather, in accordance with the Act, we conducted our own 
analyses and made our own determination based on the beast available 
information. Please see the ``Summary of Factors Affecting the 
Species'' section for in-depth discussion.
    Comment 61: The peer review process is flawed due to biases of the 
individual peer reviewers.
    Our response: We conducted our peer review in accordance with our 
policy published on July 1, 1994 (59 FR 34270), and based on our 
implementation of the OMB Final Information Quality Bulletin for Peer 
Review, dated December 16, 2004. Peer reviewers were chosen based upon 
their ability to provide independent review, their standing as experts 
in their respective disciplines as demonstrated through publication of 
articles in peer reviewed or referred journals, and their stature 
promoting an international cross-section of views. Please see ``Peer 
Review'' section above for additional discussion.
    Peer review comments are available to the public and have been 
posted on the Service's web site at: http://alaska.fws.gov/fisheries/mmm/polarbear/issues.htm. In addition to peer review comments, the 
Service also provides an open public comment process to ensure in part 
that any potential issues of bias are specifically identified to allow 
for the issue to be evaluated for merit. In our analysis of peer review 
and public comments we find that peer review comments were objective, 
balanced and without bias.
    Comment 62: Requests were received for additional public hearings 
and extension of the public comment period.
    Our response: Procedures for public participation and review in 
regard to proposed rules are provided at section 4(b)(5) of the Act, 50 
CFR 424, and the Administrative Procedure Act (5 U.S.C. 551 et 
seq.)(APA). We are obligated to hold at least one public hearing on a 
listing proposal, if requested to do so within 45 days after the 
publication of the proposal (16 U.S.C. 1533(b)(5)(E)). As described 
above, in response to requests from the public, we held three public 
hearings. We were not able to hold a public hearing that could be 
easily accessed by each and every requester, as we received comments 
from throughout the United States and many other countries. We accepted 
and considered oral comments given at the public hearings, and we 
incorporated those comments into the administrative record for this 
action. In making our decision on the proposed rule, we gave written 
comments the same weight as oral comments presented at hearings. 
Furthermore, our regulations require a 60-day comment period on 
proposed rules (50 CFR 424.16(c)(2)), but the initial public comment 
period on the proposed rule to list the polar bear was open from 
January 9 to April 9, 2007, encompassing approximately 90 days. The 
comment period was reopened for comments on new scientific information 
from September 20 through October 22, 2007, an extra 32 days. We 
believe the original 90-day comment period, three public hearings, and 
second public comment period provided ample opportunity for public 
comment, as intended under the Act, our regulations, and the APA.
    Comment 63: The Service's conclusion that this regulatory action 
does not constitute a significant energy action and that preparation of 
a ``Statement of Energy Effects'' is not required is flawed.
    Our response: In 1982, the Act was amended by the United States 
Congress to clarify that listing and delisting determinations are to be 
based on the best scientific and commercial data available (Pub. L. 97-
304, 96 Stat. 1411) to clarify that the determination was intended to 
be a biological decision and made without reference to economic or 
other non-biological factors. The specific language from the 
accompanying House Report (No. 97-567) stated, ``The principal purpose 
of the amendments to Section 4 is to ensure that decisions pertaining 
to the listing and delisting of species are based solely upon 
biological criteria and to prevent non-biological considerations from 
affecting such decisions.'' Further as noted in another U.S. House of 
Representatives Report, economic considerations have no relevance to 
determinations regarding the status of the species and the economic 
analysis requirements of Executive Order 12291, and such statutes as 
the Regulatory Flexibility Act and Paperwork Reduction Act, will not 
apply to any phase of the listing process.'' (H.R. Rep. No 835, 97th 
Cong., Sess. 19 (1982)). On the basis of the amendments to the Act put 
forth by Congress in 1982 and Congressional intent as evidenced in the 
quotation above, we have determined that the provisions of Executive 
Order 13211 ``Actions Concerning Regulations That Significantly Affect 
Energy Supply, Distribution, or Use'' (66 FR 28355), do not apply to 
listing and delisting determinations under section 4 of the Act because 
of their economic basis. Therefore, Executive Order 13211 does not 
apply to this determination to list the polar bear as threatened 
throughout its range.
    Comment 64: There is insufficient information to proceed with a 
listing, and thus our proposal was arbitrary and capricious.
    Our response: Under the APA, a court may set aside an agency 
rulemaking if found to be, among other things, ``arbitrary, capricious, 
an abuse of discretion, or otherwise not in accordance with law'' (5 
U.S.C. 706(2)(A)). The Endangered Species Act

[[Page 28251]]

requires that listing decisions be based solely on the best scientific 
and commercial information available. We have used the best available 
scientific information throughout our analysis, and have taken a number 
of steps-as required by the Act and its implementing regulations, the 
APA, and our peer review policy--to ensure that our analysis of the 
available information was balanced and objective. The evaluation of 
information contained within the final rule and all other related 
documents (e.g., the Status Review (Schliebe et al. 2006a) is a result 
of multiple levels of review and validation of information. We sought 
peer review and public comment, and incorporated all additional 
information received through these processes, where applicable. These 
steps were transparent and made available to the public for inspection, 
review, and comment. We have determined that the best available 
scientific and commercial information is sufficient to find that the 
polar bear meets the definition of a threatened species under the Act.
    Comment 65: The Service did not comply with the Information Quality 
Act and with the Service's Information Quality Guidelines.
    Our response: The Information Quality Act requires Federal agencies 
to ensure the quality, objectivity, utility, and integrity of the 
information they disseminate. ``Utility'' refers to the usefulness of 
the information to its intended users, and ``integrity'' pertains to 
the protection of the information from unauthorized access or revision. 
According to OMB guidelines (67 FR 8452), technical information that 
has been subjected to formal, independent, external peer review, as is 
performed by scientific journals, is presumed to be of acceptable 
objectivity. Literature used in the proposed rule was considered the 
best available peer-reviewed literature at the time. In addition, our 
proposed rule was peer-reviewed by 14 experts in the field of polar 
bear biology and climatology. In instances where information used in 
the proposed rule has become outdated, this final rule has been revised 
to reflect the most current scientific information. Despite being peer-
reviewed, most scientific information has some limitations and 
statements of absolute certainty are not possible. In this rule, and in 
accordance with our responsibilities under the Act, we sought to 
provide a balanced analysis by considering all available information 
relevant to the status of polar bears and potential impacts of climate 
change and by acknowledging and considering the limitations of the 
information that provided the basis for our analysis and decision-
making (see ``Summary of Factors Affecting the Polar Bear'' and ``Issue 
5: Climate Change'' for more information).
    Comment 66: National Environmental Policy Act (NEPA) compliance is 
lacking, and an Environmental Impact Statement is needed as this is a 
significant Federal action.
    Our response: The rule is exempt from NEPA procedures. In 1983, 
upon recommendation of the Council on Environmental Quality, the 
Service determined that NEPA documents are not required for regulations 
adopted pursuant to section 4(a) of the Act. A notice outlining the 
Service's reasons for this determination was published in the Federal 
Register on October 25, 1983 (48 FR 49244). A listing rule provides the 
appropriate and necessary prohibitions and authorizations for a species 
that has been determined to be threatened under section 4(a) of the 
Act. The opportunity for public comments-one of the goals of NEPA-is 
also already provided through section 4 rulemaking procedures. This 
determination was upheld in Pacific Legal Foundation v. Andrus, 657 
F.2d 829 (6th Cir. 1981).
    Comment 67: The Service should fulfill its requirement to have 
regular and meaningful consultation and collaboration with Alaska 
Native organizations in the development of this Federal action.
    Our response: As detailed in the preamble to this section of the 
final rule, we actively engaged in government-to-government 
consultation with Alaska Native Tribes in accordance with E.O. 13175 
and Secretarial Order 3225. Since 1997, the Service has worked closely 
with the Alaska Nanuuq Commission (Commission) on polar bear management 
and conservation for subsistence purposes. Not only was the Commission 
kept fully informed throughout the development of the proposed rule, 
but that organization was asked to serve as a peer reviewer of the 
Status Review (Schliebe et al. 2006a) and the proposed rule (72 FR 
1064). Following publication of the proposed rule, the Service actively 
solicited comments from Alaska Natives living within the range of the 
polar bear. We received comments on the proposed rule from seven tribal 
associations. We held a public hearing in Barrow, Alaska, to enable 
Alaska Natives to provide oral comment. We invited the 15 villages in 
the Commission to participate in the hearing, and we offered the 
opportunity to provide oral comment via teleconference. Thus, we 
believe we have fulfilled our requirement to have regular and 
meaningful consultation and collaboration with Alaska Native 
organizations in the development of this final rule.
    Comment 68: An Initial Regulatory Flexibility Analysis (IRFA) 
should be completed prior to the publication of a final rule.
    Our response: Under the Regulatory Flexibility Act (5 U.S.C. 601 et 
seq., as amended by the Small Business Regulatory Enforcement Fairness 
Act (SBREFA) of 1996), an IRFA is prepared in order to describe the 
effects of a rule on small entities (small businesses, small 
organizations, and small government jurisdictions). An IRFA is not 
prepared in a listing decision because we consider only the best 
available scientific information and do not consider economic impacts 
(please see response to Comment 70 for additional discussion).
    Comment 69: Some commenters stated that the Service should 
designate critical habitat concurrent with this rulemaking; however, 
several other commenters disagreed.
    Our response: Section 4(a)(3) of the Act requires that, to the 
maximum extent prudent and determinable, the Secretary designate 
critical habitat at the time the species is listed. Accordingly, we are 
not able to forego the process of designating critical habitat when 
doing so is prudent and critical habitat is determinable. Service 
regulations (50 CFR 424.12(a)) state that critical habitat is not 
determinable if information sufficient to perform required analyses of 
the impacts of designation is lacking or if the biological needs of the 
species are not sufficiently well known to permit identification of an 
area as critical habitat. Given the complexity and degree of 
uncertainty at this time as to which specific areas in Alaska might be 
essential to the conservation of the polar bear in the long-term under 
rapidly changing environmental conditions, we have determined that we 
will need additional time to conduct a thorough evaluation and peer 
review of a potential critical habitat designation. Thus, we are not 
publishing a proposed designation of critical habitat concurrently with 
this final listing rule, but we intend to publish a proposed 
designation in the very near future. Please see the ``Critical 
Habitat'' section below for further discussion.

Issue 9: Impacts of Listing

    Comment 70: Several comments highlighted potential impacts of 
listing, such as economic consequences, additional regulatory burden, 
and conservation benefits. Other commenters noted that economic factors 
cannot be taken into consideration at this stage of the listing.

[[Page 28252]]

    Our response: Under section 4(b)(1)(A) of the Act, we must base a 
listing decision solely on the best scientific and commercial data 
available. The legislative history of this provision clearly states the 
intent of Congress to ensure that listing decisions are ``* * * based 
solely on biological criteria and to prevent non-biological criteria 
from affecting such decisions * * *'' (see reponse to Comment PR8 for 
more details). Therefore, we did not consider the economic impacts of 
listing the polar bear. In our Notice of Interagency Cooperative Policy 
of Endangered Species Act Section 9 Prohibitions (59 FR 34272), we 
stated our policy to identify, to the extent known at the time a 
species is listed, specific activities that will not be considered 
likely to result in violation of section 9 of the Act. In accordance 
with that policy, we have published in this final rule a list of 
activities we believe will not result in violation of section 9 of the 
Act (see ``Available Conservation Measures'' section of this rule for 
further discussion). However, because the polar bear is listed as a 
threatened species and the provisions of section 4(d) of the Act 
authorize the Service to implement, by regulation, those measures 
included in section 9 of the Act that are deemed necessary and 
advisable to provide for the conservation of the species, please 
consult the special rule for the polar bear that is published in 
today's edition of the Federal Register for all of the prohibitions and 
exceptions that apply to this threatened species.
    Comment 71: Several comments were received pertaining to the 
effectiveness of listing the polar bear under the Act, specifically 
whether listing would or would not contribute to the conservation of 
the species.
    Our response: The potential efficacy of a listing action to 
conserve a species cannot be considered in making the listing decision. 
The Service must make its determination based on a consideration of the 
factors affecting the species, utilizing only the best scientific and 
commercial information available and is not able to consider other 
factors or impacts (see response to Comment 70 for additional 
discussion). Listing recognizes the status of the species and invokes 
the protection and considerations under the Act, including regulatory 
provisions, consideration of Federal activities that may affect the 
polar bear, potential critical habitat designation. The Service will 
also develop a recovery plan and a rangewide conservation strategy. 
Please see the responses to comments under ``Issue 10: Recovery'' as 
well as the ``Available Conservation Measures'' section of this rule 
for further discussion.
    Comment 72: Listing under the Act may result in additional 
regulation of industry and development activities in the Arctic. A 
discussion of incidental take authorization should be included in the 
listing rule. Some comments reflected concern regarding the perceived 
economic implications of regulatory and administrative requirements 
stemming from listing.
    Our response: Section 7(a)(2) of the Act, as amended, requires 
Federal agencies to consult with the Service to ensure that the actions 
they authorize, fund, or carry out are not likely to jeopardize the 
continued existence of listed species. Informal consultation provides 
an opportunity for the action agency and the Service to explore ways to 
modify the action to reduce or avoid adverse effects to the listed 
species or designated critical habitat. In the event that adverse 
effects are unavoidable, formal consultation is required. Formal 
consultation is a process in which the Service determines if the action 
will result in incidental take of individuals, assesses the action's 
potential to jeopardize the continued existence of the species, and 
develops an incidental take statement. Formal consultation concludes 
when the Service issues a biological opinion, including any mandatory 
measures prescribed to reduce the amount or extent of incidental take 
of the action. In the case of marine mammals, the Service must also 
ensure compliance with regulations promulgated under section 101(a)(5) 
of the MMPA. Authorization of incidental take under the MMPA is 
discussed under Factor D. Actions that are already subject to section 7 
consultation requirements in the Arctic, some of which may involve the 
polar bear, include, but are not limited to: Refuge operations and 
research permits; U.S. Army Corps of Engineers and Environmental 
Protection Agency permitting actions under the Clean Water Act and 
Clean Air Act; Bureau of Land Management land-use planning and 
management activities including onshore oil and gas leasing activities; 
Minerals Management Service administration of offshore oil and gas 
leasing activities; and Denali Commission funding of fueling and power 
generation projects.

Issue 10: Recovery

    Comment 73: Several comments identified additional research needs 
related to polar bears, their prey, indigenous people, climate, and 
anthropogenic and cumulative effects on polar bears. Some specific 
recommendations include increased research and continued monitoring of 
polar bear populations and their prey, monitoring of polar bear 
harvest, and development of more comprehensive climate change models.
    Our response: We agree that additional research would benefit the 
conservation of the polar bear. The Service will continue to work with 
the USGS, the State of Alaska, the IUCN/PBSG, independent scientists, 
indigenous people, and other interested parties to conduct research and 
monitoring on Alaska's shared polar bear populations. While the Service 
does not have appropriate resources or management responsibility for 
conducting climate research, we have and will continue to work with 
climatologists and experts from USGS, NASA, and NOAA to address polar 
bear-climate related issues. Furthermore, we will consider appropriate 
research and monitoring recommendations received from the public in the 
development of a rangewide conservation strategy.
    Comment 74: Several commenters provided recommendations for 
recovery actions, to be considered both in addition to and in lieu of 
listing. Other commenters cited the need for immediate recovery 
planning and implementation upon completion of a final listing rule.
    Our response: As discussed throughout this final rule, the Service 
has been working with Range countries on conservation actions for the 
polar bears for a number of years. Due to the significant threats to 
the polar bear's habitat, however, it is our determination that the 
polar bear meets the definition of a threatened species under the Act 
and requires listing. With completion of this final listing rule, the 
Service will continue and expand coordination with the Range countries 
regarding other appropriate international initiatives that would assist 
in the development of a rangewide conservation strategy. However, it 
must be recognized that the threats to the polar bear's habitat may 
only be addressed on a global level. Recovery planning under section 
4(f) of the Act will be limited to areas under U.S. jurisdiction, since 
the preparation of a formal recovery plan would not promote the 
conservation of polar bears in foreign countries that are not subject 
to the implementation schedules and recovery goals established in such 
a plan. However, the Service will use its section 8 authorities to 
carry out conservation measures for polar bears in cooperation with 
foreign countries.

[[Page 28253]]

Summary of Factors Affecting the Polar Bear

    Section 4 of the Act (16 U.S.C. 1533), and implementing regulations 
at 50 CFR part 424, set forth procedures for adding species to the 
Federal Lists of Endangered and Threatened Wildlife and Plants. Under 
section 4(a) of the Act, we may list a species on the basis of any of 
five factors, as follows: (A) The present or threatened destruction, 
modification, or curtailment of its habitat or range; (B) 
overutilization for commercial, recreational, scientific, or 
educational purposes; (C) disease or predation; (D) the inadequacy of 
existing regulatory mechanisms; or (E) other natural or manmade factors 
affecting its continued existence. In making this finding, the best 
scientific and commercial information available regarding the status 
and trends of the polar bear is considered in relation to the five 
factors provided in section 4(a)(1) of the Act.
    In the context of the Act, the term ``endangered species'' means 
any species or subspecies or, for vertebrates, Distinct Population 
Segment (DPS), that is in danger of extinction throughout all or a 
significant portion of its range, and a ``threatened species'' is any 
species that is likely to become an endangered species within the 
foreseeable future. The Act does not define the term ``foreseeable 
future.'' For this final rule, we have identified 45 years as the 
foreseeable future for polar bears; our rationale for selecting this 
timeframe is presented in the following section.

Foreseeable Future

    For this final rule, we have determined the ``foreseeable future'' 
in terms of the timeframe over which the best available scientific data 
allow us to reliably assess the effects of threats on the polar bear.
    The principal threat to polar bears is the loss of their primary 
habitat-sea ice. The linkage between habitat loss and corresponding 
effects on polar bear populations was hypothesized in the past (Budyko 
1966, p. 20; Lentfer 1972, p. 169; Tynan and DeMaster 1997, p. 315; 
Stirling and Derocher 1993, pp. 241-244; Derocher et al. 2004, p. 163), 
but is now becoming well established through long-term field studies 
that span multiple generations (Stirling et al. 1999, pp. 300-302; 
Stirling and Parkinson 2006, pp. 266-274; Regehr et al. 2006; Regehr et 
al. 2007a, 2007b; Rode et al. 2007, pp. 5-8; Hunter et al. 2007, pp. 8-
14; Amstrup et al. 2007).
    The timeframe over which the best available scientific data allows 
us to reliably assess the effect of threats on the species is the 
critical component for determining the foreseeable future. In the case 
of the polar bear, the key threat is loss of sea ice, the species' 
primary habitat. Sea ice is rapidly diminishing throughout the Arctic, 
and the best available evidence is that Arctic sea ice will continue to 
be affected by climate change. Recent comprehensive syntheses of 
climate change information (e.g., IPCC AR4) and additional modeling 
studies (e.g., Overland and Wang 2007a, pp. 1-7; Stroeve et al. 2007, 
pp. 1-5) show that, in general, the climate models that best simulate 
Arctic conditions all project significant losses of sea ice over the 
21st century. A key issue in determining what timeframe to use for the 
foreseeable future has to do with the uncertainty associated with 
climate model projections at various points in the future. Virtually 
all of the climate model projections in the AR4 and other studies 
extend to the end of the 21st century, so we considered whether a 
longer timeframe for the foreseeable future was appropriate. The AR4 
and other studies help clarify the scientific uncertainty associated 
with climate change projections, and allow us to make a more objective 
decision related to the timeframe over which we can reliably assess 
threats.
    Available information indicates that climate change projections 
over the next 40-50 years are more reliable than projections over the 
next 80-90 years. This is illustrated in Figure 5 above. Examination of 
the trend lines for temperature using the three emissions scenarios, as 
shown in Figure 5, illustrates that temperature increases over the next 
40-50 years are relatively insensitive to the SRES emissions scenario 
used to model the projected change (i.e., the lines in Figure 5 are 
very close to one another for the first 40-50 years). The ``limited 
sensitivity'' of the results is because the state-of-the-art climate 
models used in the AR4 have known physics connecting increases in GHGs 
to temperature increases through radiation processes (Overland and Wang 
2007a, pp. 1-7, cited in J. Overland, NOAA, in litt. to the Service, 
2007), and the GHG levels used in the SRES emissions scenarios follow 
similar trends until around 2040-2050. Because increases in GHGs have 
lag effects on climate and projections of GHG emissions can be 
extrapolated with greater confidence over the next few decades, model 
results projecting out for the next 40-50 years (near-term climate 
change estimates) have greater credibility than results projected much 
further into the future (long-term climate change) (J. Overland, NOAA, 
in litt. to the Service, 2007). Thus, the uncertainty associated with 
emissions is relatively smaller for the 45-year ``foreseeable future'' 
for the polar bear listing. After 2050, greater uncertainty associated 
with various climate mechanisms, including the carbon cycle, is 
reflected in the increasingly larger confidence intervals around 
temperature trend lines for each of the SRES emissions scenarios (see 
Figure 5). In addition, beyond 40-50 years, the trend lines diverge 
from one another due to differences among the SRES emissions scenarios. 
These SRES scenarios diverge because each makes different assumptions 
about the effects that population growth, potential technological 
improvements, societal and regulatory changes, and economic growth have 
on GHG emissions, and those differences are more pronounced after 2050. 
The divergence in the lines beyond 2050 is another source of 
uncertainty in that there is less confidence in what changes might take 
place to affect GHG emissions beyond 40-50 years from now.
    The IPCC AR4 reaches a similar conclusion about the reliability of 
projection results over the short term (40-50 years) versus results 
over the long term (80-90 years) (IPCC 2007, p. 749) in discussing 
projected changes in surface air temperatures (SATs):

    ``There is close agreement of globally averaged SAT multi-model 
mean warming for the early 21st century for concentrations derived 
from the three non-mitigated IPCC Special Report on Emission 
Scenarios (SRES: B1, A1B and A2) scenarios (including only 
anthropogenic forcing) run by the AOGCMs * * * this warming rate is 
affected little by different scenario assumptions or different model 
sensitivities, and is consistent with that observed for the past few 
decades * * *. Possible future variations in natural forcings (e.g., 
a large volcanic eruption) could change those values somewhat, but 
about half of the early 21st-century warming is committed in the 
sense that it would occur even if atmospheric concentrations were 
held fixed at year 2000 values. By mid-century (2046-2065), the 
choice of scenario becomes more important for the magnitude of 
multi-model globally averaged SAT warming * * *. About a third of 
that warming is projected to be due to climate change that is 
already committed. By late century (2090-2099), differences between 
scenarios are large, and only about 20% of that warming arises from 
climate change that is already committed.''

    On the basis of our analysis, reinforced by conclusions of the IPCC 
AR4, we have determined that climate changes projected within the next 
40-50 years are more reliable than projections for the second half of 
the 21st century.
    The 40-50 year timeframe for a reliable projection of threats to 
habitat corresponds closely to the timeframe of

[[Page 28254]]

three polar bear generations (45 years), as determined by the method 
described in the following paragraph. Long-term studies have 
demonstrated, and world experts (e.g., PBSG) are in agreement, that 
three generations is an appropriate timespan to use to reliably assess 
the status of the polar bear and the effects of threats on population-
level parameters (e.g., body condition indices, vital rates, and 
population numbers). This is based on the life history of the polar 
bear, the large natural variability associated with polar bear 
population processes, and the capacity of the species for ecological 
and behavioral adaptation (Schliebe et al. 2006a, pp. 59-60). Although 
not relied on as the basis for determining ``foreseeable future'' in 
this rule, the correspondence of this timeframe with important 
biological considerations provides greater confidence for this listing 
determination.
    Polar bears are long-lived mammals, and adults typically have high 
survival rates. Both sexes can live 20 to 25 years (Stirling and 
Derocher 2007), but few polar bears in the wild live to be older than 
20 years (Stirling 1988, p. 139; Stirling 1990, p. 225). Due to 
extremely low reproductive rates, polar bears require a high survival 
rate to maintain population levels. Survival rates increase up to a 
certain age, with cubs-of-the-year having the lowest rates and prime 
age adults (between 5 and 20 years of age) having survival rates that 
can exceed 90 percent. Generation length is the average age of parents 
of the current cohort; generation length therefore reflects the 
turnover rate of breeding individuals in a population. We adapted the 
criteria of the IUCN Red List process (IUCN 2004) for determining polar 
bear generation time in both the proposed rule (72 FR 1064) and this 
final rule. A generation span, as defined by IUCN, is calculated as the 
age of sexual maturity (5 years for polar bears) plus 50 percent of the 
length of the lifetime reproductive period (20 years for polar bears). 
The IUCN Red List process also uses a three-generation timeframe ``to 
scale the decline threshold for the species'' life history'' (IUCN 
2004), recognizing that a maximum time cap is needed for assessments 
based on projections into the future because ``the distant future 
cannot be predicted with enough certainty to justify its use'' in 
determining whether a species is threatened or endangered. Based on 
these criteria, the length of one generation for the polar bear is 15 
years, and, thus, three generations are 45 years.
    The appropriate timeframe for assessing the effects of threats on 
polar bear population status must be determined on the basis of an 
assessment of the reliability of available biological and threat 
information at each step. For polar bear, the reliability of biological 
information and, therefore, population status projections, increases if 
a multigenerational analysis is used. In general, the reliability of 
information and projections increases with time, until a point when 
reliability begins to decline again due to uncertainty in projecting 
threats and corresponding responses by polar bear populations (S. 
Schliebe, pers. comm., 2008). This decline in reliability depends on 
the level of uncertainty associated with projected threats and their 
relationship to the population dynamics of the species. With polar 
bears, we expect the reliability of population status projections to 
diminish around 4-5 generations. Thus, 3 generations is the 
optimal timeframe to reliably assess the status of the polar bear 
response to population-level threats. This progression can be 
illustrated by results from studies of the Western Hudson Bay polar 
bear population.
    In western Hudson Bay, break-up of the annual sea ice now occurs 
approximately 2.5 weeks earlier than it did 30 years ago (see 
discussion of ``Western Hudson Bay'' population under Factor A and 
Stirling and Parkinson 2006, p. 265). Stirling and colleagues measured 
mean estimated mass of lone adult female polar bears from 1980 through 
2004, and determined that their average weight declined by about 65 kg 
(143 lbs) over that period. Stirling and Parkinson (2006, p. 266) 
project that cub production could cease in 20 to 30 years if climate 
trends continue as projected by the IPCC. The overall timeframe covered 
by this scenario is 45-55 years, which is within the 3 
generation timeframe. In addition, Regehr et al. (2007a, p. 2,673) 
analyzed population trend data for 1987 through 2004 and documented a 
long-term, gradual decline in population size that is anticipated to 
continue into the future. These two lines of evidence indicate that the 
species will likely be in danger of extinction within the next 45 
years. Beyond that timeframe, the population trend and threats 
information are too uncertain to reliably project the status of the 
species.
    In summary, we considered the timeframe over which the best 
available scientific data allow us to reliably assess the effect of 
threats on the polar bear, and determined that there is substantial 
scientific reliability associated with climate model projections of sea 
ice change over the next 40-50 years. Confidence limits are much closer 
(i.e., more certain) for projections of the next 40-50 years and all 
projections agree that sea ice will continue to decrease. In 
comparison, periods beyond 50 years exhibit wider confidence limits, 
although all trends continue to express warming and loss of sea ice 
(IPCC 2007, p. 749; Overland and Wang 2007a, pp. 1-7; Stroeve et al. 
2007, pp. 1-5). This timespan compares well with the 3-generation (45-
year) timeframe over which we can reliably evaluate the effects of 
environmental change on polar bear life history and population 
parameters. Therefore, we believe that a 45-year foreseeable future is 
a reasonable and objective timeframe for analysis of whether polar 
bears are likely to become endangered.
    This 45-year timeframe for assessing the status of the species is 
consistent with the work of the PBSG in reassessing the status of polar 
bears globally in June 2005 (Aars et al. 2006, p. 31) for purposes of 
IUCN Red List classification. More than 40 technical experts were 
involved in the PBSG review (including polar bear experts from the 
range countries and other invited polar bear specialists), and these 
PBSG technical experts supported the definition of a polar bear 
generation as 15 years, and the application of three generations as the 
appropriate timeframe over which to evaluate polar bear population 
trends for the purposes of IUCN Red List categorization. Although the 
Red List process is not the same as our evaluation for listing a 
species under the Act, the basic rationale for determining generation 
length and timeframe for analysis of threats is similar in both. None 
of the experts raised an issue with the 45-year timeframe for analysis 
of population trends.
    In addition, when seeking peer review of both the Status Review 
(Schliebe et al. 2006a) and the proposed rule to list the polar bear as 
threatened (72 FR 1064), we specifically asked peer reviewers to 
comment on the 45-year foreseeable future and the method we used to 
derive that timeframe. All reviewers that commented on this subject 
indicated that a 45-year timeframe for the foreseeable future was 
appropriate, with the exception of one reviewer who thought the 
foreseeable future should be 100 years. Thus, both the independent 
reviews by PBSG and the input from peer reviewers corroborate our final 
decision and our rationale for using 45 years as the foreseeable future 
for the polar bear.

[[Page 28255]]

    Our evaluation of the five factors with respect to polar bear 
populations is presented below. We considered all relevant available 
scientific and commercial information under each of the listing factors 
in the context of the present-day distribution of the polar bear.

Factor A. Present or Threatened Destruction, Modification, or 
Curtailment of the Polar Bear's Habitat or Range

Introduction

    As described in detail in the ``Species Biology'' section of this 
rule, polar bears are evolutionarily adapted to life on sea ice 
(Stirling 1988, p. 24; Amstrup 2003, p. 587). They need sea ice as a 
platform for hunting, for seasonal movements, for travel to terrestrial 
denning areas, for resting, and for mating (Stirling and Derocher 1993, 
p. 241). Moore and Huntington (in press) classify polar bears as an 
``ice-obligate'' species because of their reliance on sea ice as a 
platform for resting, breeding, and hunting. Laidre et al. (in press) 
similarly describe the polar bear as a species that principally relies 
on annual sea ice over the continental shelf and areas toward the 
southern extent of the edge of sea ice for foraging. Some polar bears 
use terrestrial habitats seasonally (e.g., for denning or for resting 
during open water periods). Open water by itself is not considered to 
be a habitat type frequently used by polar bears, because life 
functions such as feeding, reproduction, or resting do not occur in 
open water. However, open water is a fundamental part of the marine 
system that supports seal species, the principal prey of polar bears, 
and seasonally refreezes to form the ice needed by the bears (see 
``Open Water Habitat'' section for more information). In addition, the 
extent of open water is important because vast areas of open water may 
limit a bear's ability to access sea ice or land (see ``Open Water 
Swimming'' section for more detail). Snow cover, both on land and on 
sea ice, is an important component of polar bear habitat in that it 
provides insulation and cover for young polar bears and ringed seals in 
snow dens or lairs on sea ice (see ``Maternal Denning Habitat'' section 
for more detail).

Previous Warming Periods and Polar Bears

    Genetic evidence indicates that polar bears diverged from grizzly 
bears between 200,000-400,000 years ago (Talbot and Shields 1996a, p. 
490; Talbot and Shields 1996b, p. 574); however, polar bears do not 
appear in the fossil record until the Last Interglacial Period (LIG) 
(115,000-140,000 years ago) (Kurten 1964, p. 25; Ingolfsson and Wiig 
2007). Depending on the exact timing of their divergence, polar bears 
may have experienced several periods of climatic warming, including a 
period 115,000-140,000 years ago, a period of warming 4,000-12,000 
years ago (Holocene Thermal Maximum), and most recently during medieval 
times (800 to 1200 A.D.). During these periods there is evidence 
suggesting that regional air temperatures were higher than present day 
and that sea ice and glacial ice were significantly reduced 
(Circumpolar Arctic PaleoEnvironments (CAPE) 2006, p. 1394; Jansen et 
al. 2007, p. 435, 468). This section considers historical information 
available on polar bears and the environmental conditions during these 
warming periods.
    During the LIG (115,000-140,000 years ago), some regions of the 
world including parts of the Arctic experienced warmer than present day 
temperatures as well as greatly reduced sea ice in some areas, 
including what is now coastal Alaska and Greenland (Jansen et al. 2007, 
p. 453). CAPE (2006, p.1393) concludes that all sectors of the Arctic 
were warmer than present during the LIG, but that the magnitude of 
warming was not uniform across all regions of the Arctic. Summer 
temperature anomalies at lower Northern Hemisphere latitudes below the 
Arctic were not as pronounced as those at higher latitudes but still 
are estimated to have ranged from 0-2 degrees C above present (CAPE 
2006, p. 1394). Furthermore, according to the IPCC, while the average 
temperature when considered globally during the LIG was not notably 
higher than present day, the rate of warming averaged 10 times slower 
than the rate of warming during the 20th century (Jansen et al. 2007, 
p. 453). However, the rate at which change occurred may have been more 
rapid regionally, particularly in the Arctic (CAPE 2006, p. 1394). 
While the specific responses of polar bears to regional changes in 
climate during the LIG are not known, they may have survived regional 
warming events by altering their distribution and/or retracting their 
range. Similar range retraction is projected for polar bears in the 
21st century (Durner et al. 2007). However, the slower rate of climate 
change and more regional scale of change during the LIG suggest that 
polar bears had more opportunity to adapt during this time in 
comparison to the current observed and projected relatively rapid, 
global climate change (Jansen et al. 2007, p. 776; Lemke et al. 2007, 
p. 351).
    The HTM 4,000-12,000 years ago also appears to have affected 
climate Arctic-wide, though summer temperature anomalies were lower 
than those that occurred during the LIG (CAPE 2006, p. 1394). Kaufman 
et al. (2003, p. 545) report that mean surface temperatures during the 
HTM were 1.6  0.8 degrees C (range: 0.5-3 degrees C) higher 
in terrestrial habitats and 3.8  1.9 degrees C at marine 
sites than present-day temperatures at 120 sites throughout the western 
Arctic (Northeast Russia to Iceland, including all of North America). 
Furthermore, Birks and Amman (2000, pp. 1,392-1,393) provide evidence 
that change in some areas may have been rapid, including an increase of 
0.2-0.3 degrees C per 25 years in Norway and Switzerland. However, the 
timing of warming across the Arctic was not uniform, with Alaska and 
northwest Canada experiencing peak warming 4,000 years prior to 
northeast Canada (Kaufman et al. 2004, p. 529). Thus while regional 
changes in temperature are believed to have occurred, the IPCC 
concluded that annual global mean temperatures were not warmer than 
present day any time during the Holocene (Jansen et al. 2007, p. 465). 
While polar bears did experience warmer temperatures in their range 
during this time, the regional nature of warming that occurred may have 
aided their survival through this period in certain areas. However, the 
degree to which polar bears may have been impacted either regionally or 
Arctic-wide is unknown.
    The most recent period of warming occurred during the Medieval 
period (generally considered to be the period from 950 to 1300 AD). 
This episode again appears to have been regional rather than global 
(Broecker 2001, p. 1,497; Jansen et al. 2007, p. 469); additionally, 
temperatures during this period are estimated to be 0.1-0.2 degrees C 
below the 1961 to 1990 mean and significantly below the instrumental 
data after 1980 (Jansen et al. 2007, p. 469). Thus, temperatures and 
rate of change estimated for this time period do not appear comparable 
to present day conditions.
    Unfortunately, the limited scientific evidence currently available 
to us for these time periods does limit our ability to assess how polar 
bears responded to previous warming events. For example, while genetic 
analyses can be useful for identifying significant reductions in 
population size throughout a species' history (Hedrick 1996, p. 897; 
Driscoll et al. 2002, p. 414), most genetic studies of polar bears have 
focused on analyzing

[[Page 28256]]

variation in micro-satellite DNA for the purposes of differentiating 
populations (i.e., identifying genetic structure; Paetkau et al. 1995, 
p. 347; Paetkau et al. 1999, p. 1,571; Cronin et al. 2006, p. 655). 
Additionally, genetic analyses for the purpose of identifying 
population bottlenecks require accurate quantification of mutation 
rates to determine how far back in time an event can be detected and a 
combination of mitochondrial and nuclear DNA analyses to eliminate 
potential alternative factors, other than a population bottleneck, that 
might result in or counteract low genetic variation (Driscoll et al. 
2002, pp. 420-421; Hedrick 1996, p. 898; Nystrom et al. 2006, p. 84). 
The results of micro-satellite studies for polar bears have documented 
that within-population genetic variation is similar to black and 
grizzly bears (Amstrup 2003, p. 590), but that among populations, 
genetic structuring or diversity is low (Paetkau et al. 1995, p. 347; 
Cronin et al. 2006, pp. 658-659). The latter has been attributed with 
extensive population mixing associated with large home ranges and 
movement patterns, as well as the more recent divergence of polar bears 
in comparison to grizzly and black bears (Talbot and Shields 1996a, p. 
490; Talbot and Shields 1996b, p. 574; Paetkau et al. 1999, p. 1,580). 
Inferring whether the degree of genetic variation from these studies is 
indicative of a population bottleneck, however, requires additional 
analyses that have yet to be conducted. Furthermore, the very limited 
fossil record of polar bears sheds little light on possible population-
level responses of polar bears to previous warming events (Derocher et 
al. 2004, p. 163).
    Thus, while polar bears as a species have survived at least one 
period of regional warming greater than present day, it is important to 
recognize that the degree that they were impacted is not known and 
there are differences between the circumstances surrounding historical 
periods of climate change and present day. First, the IPCC concludes 
that the current rate of global climate change is much more rapid and 
very unusual in the context of past changes (Jansen et al. 2007, p. 
465). Although large variation in regional climate has been documented 
in the past 200,000 years, there is no evidence that mean global 
temperature increased at a faster rate than present warming (Jansen et 
al. 2007, p. 465), nor is there evidence that these changes occurred at 
the same time across regions. Furthermore, projected rates of future 
global change are much greater than rates of global temperature 
increase during the past 50 million years (Jansen et al. 2007, p. 465). 
Derocher et al. (2004, p. 163, 172) suggest that this rate of change 
will limit the ability of polar bears to respond and survive in large 
numbers. Secondly, polar bears today experience multiple stressors that 
were not present during historical warming periods. As explained 
further under Factors B, C, and E, polar bears today contend with 
harvest, contaminants, oil and gas development, and additional 
interactions with humans (Derocher et al. 2004, p. 172) that they did 
not experience in previous warming periods, whereas during the HTM, 
humans had just begun to colonize North America. Thus, both the 
cumulative effects of multiple stressors and the rapid rate of climate 
change today create a unique and unprecedented challenge for present-
day polar bears in comparison to historical warming events.

Effects of Sea Ice Habitat Change on Polar Bears

    Observed and predicted changes in sea ice cover, characteristics, 
and timing have profound effects on polar bears (Derocher and Stirling 
1996, p. 1,250; Stirling et al. 1999, p. 294; Stirling and Parkinson 
2006, p. 261; Regehr et al. 2007b, p. 18). As noted above, sea ice is a 
highly dynamic habitat with different types, forms, stages, and 
distributions that all operate as a complex matrix in determining 
biological productivity and use by marine organisms, including polar 
bears and their primary prey base, ice seal species. Polar bear use of 
sea ice is not uniform. Their preferred habitat is the annual ice 
located over the continental shelf and inter-island archipelagos that 
circle the Arctic basin. Ice seal species demonstrate a similar 
preference for these ice habitats.
    In the Arctic, Hudson Bay, Canada has experienced some of the 
earliest ice changes due to its southerly location on a divide between 
a warming and a cooling region (Arctic Monitoring Assessment Program 
(AMAP) 2003, p. 22), making it an ideal area to study the impacts of 
climate change. In addition, Hudson Bay has the most extensive long-
term data on the ecology of polar bears and is the location where the 
first evidence of major and ongoing impacts to polar bears from sea ice 
changes has been documented. Many researchers over the past 40 years 
have predicted an array of impacts to polar bears from climatic change 
that include adverse effects on denning, food chain disruption, and 
prey availability (Budyko 1966, p. 20; Lentfer 1972, p. 169; Tynan and 
DeMaster 1997, p. 315; Stirling and Derocher 1993, pp. 241-244). 
Stirling and Derocher (1993, p. 240) first noted changes, such as 
declining body condition, lowered reproductive rates, and reduced cub 
survival, in polar bears in western Hudson Bay; they attributed these 
changes to a changing ice environment. Subsequently, Stirling et al. 
(1999, p. 303) established a statistically significant link between 
climate change in western Hudson Bay, reduced ice presence, and 
observed declines in polar bear physical and reproductive parameters, 
including body condition (weight) and natality. More recently Stirling 
and Parkinson (2006, p. 266) established a statistically significant 
decline in weights of lone and suspected pregnant adult female polar 
bears in western Hudson Bay between 1988 and 2004. Reduced body weights 
of adult females during fall have been correlated with subsequent 
declines in cub survival (Atkinson and Ramsay 1995, p. 559; Derocher 
and Stirling 1996, p. 1,250; Derocher and Wiig 2002, p. 347).

Increased Polar Bear Movements

    The best scientific data available suggest that polar bears are 
inefficient moving on land and expend approximately twice the average 
energy than other mammals when walking (Best 1982, p. 63; Hurst 1982, 
p. 273). However, further research is needed to better understand the 
energy dynamics of this highly mobile species. Studies have shown that, 
although sea ice circulation in the Arctic is clockwise, polar bears 
tend to walk against this movement to maintain a position near 
preferred habitat within large geographical home ranges (Mauritzen et 
al. 2003a, p. 111). Currently, ice thickness is diminishing (Rothrock 
et al. 2003, p. 3649; Yu et al. 2004) and movement of sea ice out of 
the polar region has occurred (Lindsay and Zhang 2005). As the climate 
warms, and less multi-year ice is present, we expect to see a decrease 
in the export of multi-year ice (e.g., Holland et al. 2006, pp. 1-5). 
Increased rate and extent of ice movements will, in turn, require 
additional efforts and energy expenditure by polar bears to maintain 
their position near preferred habitats (Derocher et al. 2004, p. 167). 
This may be an especially important consideration for females 
encumbered with small cubs. Ferguson et al. (2001, p. 51) found that 
polar bears inhabiting areas of highly dynamic ice had much larger 
activity areas and movement rates compared to those bears inhabiting 
more stable, persistent ice habitat.

[[Page 28257]]

Although polar bears are capable of living in areas of highly dynamic 
ice movement, they show inter-annual fidelity to the general location 
of preferred habitat (Mauritzen et al. 2003b, p. 122; Amstrup et al. 
2000b, p. 963).
    As sea ice becomes more fragmented, polar bears would likely use 
more energy to maintain contact with consolidated, higher concentration 
ice, because moving through highly fragmented sea ice is more energy-
intensive than walking over consolidated sea ice (Derocher et al. 2004, 
p. 167). During summer periods, the remaining ice in much of the 
central polar basin is now positioned away from more productive 
continental shelf waters and occurs over much deeper, less productive 
waters, such as in the Beaufort and Chukchi Seas of Alaska. If the 
width of leads or extent of open water increases, the transit time for 
bears and the need to swim or to travel will increase (Derocher et al. 
2004, p. 167). Derocher et al. (2004, p. 167) suggest that as habitat 
patch sizes decrease, available food resources are likely to decline, 
resulting in reduced residency time and increased movement rates. The 
consequences of increased energetic costs to polar bears from increased 
movements are likely to be reduced body weight and condition, and a 
corresponding reduction in survival and recruitment rates (Derocher et 
al. 2004, p. 167).
    Additionally, as movement of sea ice increases and areas of 
unconsolidated ice also increase, some bears are likely to lose contact 
with the main body of ice and drift into unsuitable habitat from which 
it may be difficult to return (Derocher et al. 2004, p. 167). This has 
occurred historically in some areas such as Southwest Greenland as a 
result of the general drift pattern of sea ice in the area (Vibe 1967) 
and also occurs offshore of Newfoundland, Canada (Derocher et al. 2004, 
p. 167). Increased frequency of such events could negatively impact 
survival rates and contribute to population declines (Derocher et al. 
2004, p. 167).

Polar Bear Seasonal Distribution Patterns Within Annual Activity Areas

    Increasing temperatures and reductions in sea ice thickness and 
extent, coupled with seasonal retraction of sea ice poleward, will 
cause redistribution of polar bears seasonally into areas previously 
used either irregularly or infrequently. While polar bears have 
demonstrated a wide range of space-use patterns within and between 
populations, the continued retraction and fragmentation of sea ice 
habitats that is projected to occur will alter previous patterns of use 
seasonally and regionally. These changes have been documented at an 
early onset stage for a number of polar bear populations with the 
potential for large-scale shifts in distribution by the end of the 21st 
century (Durner et al. 2007, pp. 18-19).
    This section provides examples of distribution changes and 
interrelated consequences. Recent studies indicate that polar bear 
movements and seasonal fidelity to certain habitat areas are changing 
and that these changes are strongly correlated to similar changes in 
sea ice and the ocean-ice system. Changes in movements and seasonal 
distributions can have effects on polar bear nutrition, body condition, 
and more significant longer term redistribution. Specifically, in 
western Hudson Bay, break-up of the annual sea ice now occurs 
approximately 2.5 weeks earlier than it did 30 years ago (Stirling et 
al. 1999, p. 299). The earlier spring break-up was highly correlated 
with dates that female polar bears came ashore (Stirling et al. 1999, 
p. 299). Declining reproductive rates, subadult survival, and body mass 
(weights) have occurred because of longer periods of fasting on land as 
a result of the progressively earlier break-up of the sea ice and the 
increase in spring temperatures (Stirling et al. 1999, p. 304; Derocher 
et al. 2004, p. 165).
    Stirling et al. (1999, p. 304) cautioned that, although downward 
trends in the size of the Western Hudson Bay population had not been 
detected, if trends in life history parameters continued downward, 
``they will eventually have a detrimental effect on the ability of the 
population to sustain itself.'' Subsequently, Parks et al. (2006, p. 
1282) evaluated movement patterns of adult female polar bears 
satellite-collared from 1991 to 2004 with respect to their body 
condition. Reproductive status and variation in ice patterns were 
included in the analysis. Parks et al. (2006, p. 1281) found that 
movement patterns were not dependent on reproductive status of females 
but did change significantly with season. They found that annual 
distances moved had decreased in Hudson Bay since 1991. This suggested 
that declines in body condition were due to reduced prey consumption as 
opposed to increased energy output from movements (Parks et al. 2006, 
p. 281). More recently, Regehr et al. (2007a, p. 2,673) substantiated 
Stirling et al.'s (1999, p. 304) predictions, noting population 
declines in western Hudson Bay during analysis of data from an ongoing 
mark-recapture population study. Between 1987 and 2004, the number of 
polar bears in the Western Hudson Bay population declined from 1,194 to 
935, a reduction of about 22 percent (Regehr et al. 2007a, p. 2,673). 
Progressive declines in the condition and survival of cubs, subadults, 
and bears 20 years of age and older appear to have been caused by 
progressively earlier sea ice break-up, and likely initiated the 
decline in population. Once the population began to decline, existing 
harvest rates contributed to the reduction in the size of the 
population (Regehr et al. 2007a, p. 2,680).
    Since 2000, Schliebe et al. (2008) observed increased use of 
coastal areas by polar bears during the fall open-water period in the 
southern Beaufort Sea. High numbers of bears (a minimum of 120) were 
found to be using coastal areas during some years, where prior to the 
1990s, according to native hunters, industrial workers, and researchers 
operating on the coast at this time of year, such observations of polar 
bears were rare. This study period (2000-2005) also included record 
minimal sea ice conditions for the month of September in 4 of the 6 
survey years. Polar bear density along the mainland coast and on 
barrier islands during the fall open water period in the southern 
Beaufort Sea was related to distance from pack ice edge and the density 
of ringed seals over the continental shelf. The distance between pack 
ice edge and the mainland coast, as well as the length of time that 
these distances prevailed, was directly related to polar bear density 
onshore. As the sea ice retreated and the distance to the edge of the 
ice increased, the number of bears near shore increased. Conversely, as 
near-shore areas became frozen or sea ice advanced toward shore, the 
number of bears near shore decreased (Schliebe et al. 2008). The 
presence of subsistence-harvested bowhead whale carcasses and their 
relationship to polar bear distribution were also analyzed. These 
results suggest that, while seal densities near shore and availability 
of bowhead whale carcasses may play a role in polar bear distribution 
changes, that sea ice conditions (possibly similar to conditions 
observed in western Hudson Bay) are influencing the distribution of 
polar bears in the southern Beaufort Sea. They also suggest that 
increased polar bear use of coastal areas may continue if the summer 
retreat of the sea ice continues into the future as predicted (Serreze 
et al. 2000, p. 159; Serreze and Barry 2005).
    Others have observed increased numbers of polar bears in novel 
habitats. During bowhead whale surveys conducted in the southern 
Beaufort Sea during September, Gleason et al. (2006)

[[Page 28258]]

observed a greater number of bears in open water and on land during 
surveys in 1997-2005, years when sea ice was often absent from their 
study area, compared to surveys conducted between 1979-1996, years when 
sea ice was a predominant habitat within their study area. Bears in 
open water likely did not select water as a choice habitat, but rather 
were swimming in an attempt to reach offshore pack ice or land. Their 
observation of a greater number of bears on land during the later 
period was concordant with the observations of Schliebe et al. (2008). 
Further, the findings of Gleason et al. (2006) coincide with the lack 
of pack ice (concentrations of greater than 50 percent) caused by a 
retraction of ice in the study area during the latter period (Stroeve 
et al. 2005, p. 2; Comiso 2003, p. 3,509; Comiso 2005, p. 52). The 
findings of Gleason et al. (2006) confirm an increasing use of coastal 
areas by polar bears in the southern Beaufort Sea in recent years and a 
decline in ice habitat near shore. The immediate causes for changes in 
polar bear distribution are thought to be (1) retraction of pack ice 
far to the north for greater periods of time in the fall and (2) later 
freeze-up of coastal waters.
    Other polar bear populations exhibiting seasonal distribution 
changes with larger numbers of bears on shore have been reported. 
Stirling and Parkinson (2006, pp. 261-275) provide an analysis of pack 
ice and polar bear distribution changes for the Baffin Bay, Davis 
Strait, Foxe Basin, and Hudson Bay populations. They indicate that 
earlier sea ice break-up will likely result in longer periods of 
fasting for polar bears during the extended open-water season. This may 
explain why more polar bears have been observed near communities and 
hunting camps in recent years. Seasonal distribution changes of polar 
bears have been noted during a similar period of time for the northern 
coast of Chukotka (Kochnev 2006, p. 162) and on Wrangel Island, Russia 
(Kochnev 2006, p. 162; N. Ovsyanikov, Russian Federation Nature 
Reserves, pers. comm.). The relationship between the maximum number of 
polar bears, the number of dead walruses, and the distance to the ice 
edge from Wrangel Island was evaluated. The subsequent results revealed 
that the most significant correlation was between bear numbers and 
distance to the ice-edge (Kochnev 2006, p. 162), which again supports 
the observation that when sea ice retreats far off shore, the numbers 
of bears present or stranded on land appears to increase.
    In Baffin Bay, traditional Inuit knowledge studies and anecdotal 
reports indicate that in many areas greater numbers of bears are being 
encountered on land during the summer and fall open-water seasons 
(Dowsley 2005, p. 2). Interviews with elders and senior hunters 
(Dowsley and Taylor 2005, p. 2) in three communities in Nunavut, 
Canada, revealed that most respondents (83 percent) believed that the 
population of polar bears had increased. The increase was attributed to 
more bears seen near communities, cabins, and camps; hunters also 
encountered bear sign (e.g., tracks, scat) in areas not previously used 
by bears. Some people interviewed noted that these observations could 
reflect a change in bear behavior rather than an increase in 
population. Many (62 percent) respondents believed that bears were less 
fearful of humans now than 15 years ago. Most (57 percent) respondents 
reported bears to be skinnier now, and five people in one community 
reported an increase in fighting among bears. Respondents also 
discussed climate change, and they indicated that there was more 
variability in the sea ice environment in recent years than in the 
past. Some respondents indicated a general trend for ice floe edge to 
be closer to the shore than in the past, the sea ice to be thinner, 
fewer icebergs to be present, and glaciers to be receding. Fewer 
grounded icebergs, from which shorefast ice forms and extends, were 
thought to be partially responsible for the shift of the ice edge 
nearer to shore. Respondents were uncertain if climate change was 
affecting polar bears or what form the effects may be taking (Dowsley 
2005, p. 1). Also, results from an interview survey of 72 experienced 
polar bear hunters in Northwest Greenland in February 2006 indicate 
that during the last 10-20 years, polar bears have occurred closer to 
the coast. Several of those interviewed believed the change in 
distribution represented an increase in the population size (e.g., Kane 
Basin and Baffin Bay), although others suggested that it may be an 
effect of a decrease in the sea ice (Born et al., in prep).
    Recently Vladilen Kavry, former Chair of the Union of Marine Mammal 
Hunters of Chukotka, Russia, Polar Bear Commission, conducted a series 
of traditional ecological knowledge interviews with indigenous Chukotka 
coastal residents regarding their impression of environmental changes 
based on their lifetime of observations (Russian Conservation News No. 
41 Spring/Summer 2006). The interviewees included 17 men and women 
representing different age and ethnic groups (Chukchi, Siberian Yupik, 
and Russian) in Chukotka, Russia. Respondents noted that across the 
region there was a changing seasonal weather pattern with increased 
unpredictability and instability of weather. Respondents noted shorter 
winters, observing that the fall-winter transition was occurring later, 
and spring weather was arriving earlier. Many described these 
differences as resulting in a one-month-later change in the advent of 
fall and one-month-earlier advent of spring. One 71-year-old Chukchi 
hunter believed that winter was delayed two months and indicated that 
the winter frosts that had previously occurred in September were now 
taking place in November. He also noted that thunderstorms were more 
frequent. Another 64-year-old hunter noted uncharacteristic snow storms 
and blizzards as well as wintertime rains. He also noted that access to 
sea ice by hunters was now delayed from the normal access date of 
November to approximately one month later into December. This 
individual also noted that blizzards and weather patterns had changed 
and that snow is more abundant and wind patterns caused snow drifts to 
occur in locations not previously observed. With increased spring 
temperatures, lagoons and rivers are melting earlier. The sea ice 
extent has declined and the quality of ice changed. The timing of fall 
sea ice freezing is delayed two months into November. The absence of 
sea ice in the summer is thought to have caused walrus to use land 
haulouts for resting in greater frequency and numbers than in the past.
    Stirling and Parkinson (2006, p. 263) evaluated sea ice conditions 
and distribution of polar bears in five populations in Canada: Western 
Hudson Bay, Eastern Hudson Bay, Baffin Bay, Foxe Basin, and Davis 
Strait. Their analysis of satellite imagery beginning in the 1970s 
indicates that the sea ice is breaking up at progressively earlier 
dates, so bears must fast for longer periods of time during the open-
water season. Stirling and Parkinson (2006, pp. 271-272) point out that 
long-term data on population size and body condition of bears from the 
Western Hudson Bay population, and population and harvest data from the 
Baffin Bay population, indicate that these populations are declining or 
likely to be declining. The authors indicate that as bears in these 
populations become more nutritionally stressed, the numbers of animals 
will decline, and the declines will probably be significant. Based on 
the recent findings of Holland et al.

[[Page 28259]]

(2006, pp. 1-5) regarding sea ice changes, these events are predicted 
to occur within the foreseeable future as defined in this rule 
(Stirling, pers. comm. 2006).
    Seasonal polar bear distribution changes noted above, the negative 
effect of reduced access to primary prey, and prolonged use of 
terrestrial habitat are a concern for polar bears. Although polar bears 
have been observed using terrestrial food items such as blueberries 
(Vaccinium sp.), snow geese (Anser caerulescens), and reindeer 
(Rangifer tarandus), these alternate foods are not believed to 
represent significant sources of energy (Ramsay and Hobson 1991, p. 
600; Derocher et al. 2004, p. 169) because they do not provide the high 
fat, high caloric food source that seals do. Also, the potential 
inefficiency of polar bear locomotion on land noted above may explain 
why polar bears are not known to regularly hunt musk oxen (Ovibos 
moschatus) or snow geese, despite their occurrence as potential prey in 
many areas (Lunn and Stirling 1985, p. 2,295). The energy needed to 
catch such species would almost certainly exceed the amount of energy a 
kill would provide (Lunn and Stirling 1985, p. 2,295). Consequently, 
greater use of terrestrial habitats as a result of reduced presence of 
sea ice seasonally will not offset energy losses resulting from 
decreased seal consumption. Nutritional stress appears to be the only 
possible result.

Effects of Sea Ice Habitat Changes on Polar Bear Prey

Reduced Seal Productivity

    Polar bear populations are known to fluctuate with prey abundance 
(Stirling and Lunn 1997, p. 177). Declines in ringed and bearded seal 
numbers and productivity have resulted in marked declines in polar bear 
populations (Stirling 1980, p. 309; Stirling and [Oslash]ritsland 1995, 
p. 2,609; Stirling 2002, p. 68). Thus, changes in ringed seal 
productivity have the potential to affect polar bears directly as a 
result of reduced predation on seal pups and indirectly through reduced 
recruitment of this important prey species. Ringed seal productivity is 
dependent on the availability of secure habitat for birth lairs and 
rearing young and, as a result, is susceptible to changes in sea ice 
and snow dynamics. Ringed seal pups are the smallest of the seals and 
survive because they are born in snow lairs (subnivian dens) that 
afford protection from the elements and from predation (Hall 1866; 
Chapskii 1940; McLaren 1958; Smith and Stirling 1975, all cited in 
Kelly 2001, p. 47). Pups are born between mid-March and mid-April, 
nursed for about 6 weeks, and weaned prior to spring break-up in June 
(Smith 1980, p. 2,201; Stirling 2002, p. 67). During this time period, 
both ringed seal pups and adults are hunted by polar bears (Smith 1980, 
p. 2,201). Stirling and Lunn (1997, p. 177) found that ringed seal 
young-of-the-year represented the majority of the polar bear diet, 
although the availability of ringed seal pups from about mid-April to 
ice break up sometime in July (Stirling and Lunn 1997, p. 176) is also 
important to polar bears.
    In many areas, ringed seals prefer to create birth lairs in areas 
of accumulated snow on stable, shore-fast ice over continental shelves 
along Arctic coasts, bays, and inter-island channels (Smith and Hammill 
1981, p. 966). While some authors suggest that landfast ice is the 
preferred pupping habitat of ringed seals due to its stability 
throughout the pupping and nursing period (McLaren 1958, p. 26; Burns 
1970, p. 445), others have documented ringed seal pupping on drifting 
pack ice both nearshore and offshore (Burns 1970; Smith 1987; Finley et 
al. 1983, p. 162; Wiig et al. 1999, p. 595; Lydersen et al. 2004). 
Either of these habitats can be affected by earlier warming and break-
up in the spring, which shortens the length of time pups have to grow 
and mature (Kelly 2001, p. 48; Smith and Harwood 2001). Harwood et al. 
(2000, pp. 11-12) reported that an early spring break-up negatively 
impacted the growth, condition, and apparent survival of unweaned 
ringed seal pups. Early break-up was believed to have interrupted 
lactation in adult females, which in turn, negatively affected the 
condition and growth of pups. Earlier ice break-ups similar to those 
documented by Harwood et al. (2000, p. 11) and Ferguson et al. (2005, 
p. 131) are predicted to occur more frequently with warming 
temperatures, and result in a predicted decrease in productivity and 
abundance of ringed seals (Ferguson et al. 2005, p. 131; Kelly 2001). 
Additionally, high fidelity to birthing sites exhibited by ringed seals 
makes them more susceptible to localized impacts from birth lair snow 
degradation, harvest, or human activities (Kelly 2006, p. 15).
    Unusually heavy ice has also been documented to result in markedly 
lower productivity of ringed seals and reduced polar bear productivity 
(Stirling 2002, p. 59). While reduced ice thickness associated with 
warming in some areas could be expected to improve seal productivity, 
the transitory and localized benefits of reduced ice thickness on 
ringed seals are expected to be outweighed by the negative effects of 
increased vulnerability of seal pups to predation and thermoregulatory 
costs (Derocher et al. 2004, p. 168). The number of studies that have 
documented negative effects associated with earlier warming and break-
up and reduced snow cover (Hammill and Smith 1989, p. 131; Harwood et 
al. 2000, p. 11; Smith et al. 1991; Stirling and Smith 2004, p. 63; 
Ferguson et al. 2005, p. 131), in comparison to any apparent benefits 
of reduced ice thickness further support this conclusion.
    Snow depth on the sea ice, in addition to the timing of ice break-
up, appears to be important in affecting the survival of ringed seal 
pups. Ferguson et al. (2005, pp. 130-131) attributed decreased snow 
depth in April and May with low ringed seal recruitment in western 
Hudson Bay. Reduced snowfall results in less snow drift accumulation on 
the leeward side of pressure ridges; pups in lairs with thin snow roofs 
are more vulnerable to predation than pups in lairs with thick roofs 
(Hammill and Smith 1989, p.131; Ferguson et al. 2005, p. 131). Access 
to birth lairs for thermoregulation is also considered to be crucial to 
the survival of nursing pups when air temperatures fall below 0 degrees 
C (Stirling and Smith 2004, p. 65). Warming temperatures that melt 
snow-covered birth lairs can result in pups being exposed to ambient 
conditions and suffering from hypothermia (Stirling and Smith 2004, p. 
63). Others have noted that when lack of snow cover has forced birthing 
to occur in the open, nearly 100 percent of pups died from predation 
(Kumlien 1879; Lydersen et al. 1987; Lydersen and Smith 1989, p. 489; 
Smith and Lydersen 1991; Smith et al. 1991, all cited in Kelly 2001, p. 
49). More recently, Kelly et al. (2006, p. 11) found that ringed seal 
emergence from lairs was related to structural failure of the snow 
pack, and PM satellite measurements indicating liquid moisture in snow. 
These studies suggest that warmer temperatures have and will continue 
to have negative effects on ringed seal pup survival, particularly in 
areas such as western Hudson Bay (Ferguson et al. 2005, p. 121).
    Similar to earlier spring break-up or reduced snow cover, increased 
rain-on-snow events during the late winter also negatively impact 
ringed seal recruitment by damaging or eliminating snow-covered pupping 
lairs, increasing exposure and the risk of hypothermia, and 
facilitating predation by polar bears and Arctic foxes (Alopex lagopus) 
(Stirling and Smith 2004, p. 65). Stirling and Smith (2004, p. 64) 
document the

[[Page 28260]]

collapse of snow roofs of ringed seal birth lairs associated with rain 
events near southeastern Baffin Island and the resultant exposure of 
adult seals and pups to hypothermia. Predation of pups by polar bears 
was observed, and the researchers suspect that most of the pups in 
these areas were eventually killed by polar bears (Stirling and 
Archibald 1977, p. 1,127), Arctic foxes (Smith 1976, p. 1,610) or 
possibly gulls (Lydersen and Smith 1989). Stirling and Smith (2004, p. 
66) postulated that should early season rain become regular and 
widespread in the future, mortality of ringed seal pups will increase, 
especially in more southerly parts of their range. Any significant 
decline in ringed seal numbers, especially in the production of young, 
could negatively affect reproduction and survival of polar bears 
(Stirling and Smith 2004, p. 66).
    Changes in snow and ice conditions can also have impacts on polar 
bear prey other than ringed seals (Born 2005a, p. 152). These species 
include harbor seals (Phoca vitulina), spotted seals (Phoca largha), 
and ribbon seals (Phoca fasciata), and in the north Atlantic, harp 
seals (Phoca greenlandica) and hooded seals (Crystophora cristata). The 
absence of ice in southerly pupping areas or the relocation of pupping 
areas for other ice-dependent seal species to more northerly areas has 
been demonstrated to negatively affect seal production. For example, 
repeated years of little or no ice in the Gulf of St. Lawrence resulted 
in almost zero production of harp seal pups, compared to hundreds of 
thousands in good ice years (ACIA 2005, p. 510). Marginal ice 
conditions and early ice break-up during harp seal whelping (pupping) 
are believed to have resulted in increased juvenile mortality from 
starvation and cold stress and an overall reduction in this age class 
(Johnston et al. 2005, pp. 215-216). Northerly shifts of whelping areas 
for hooded seals were reported to occur during periods of warmer 
climate and diminished ice (Burns 2002, p. 42). In recent years, the 
location of a hooded seal whelping patch near Jan Mayen, in East 
Greenland, changed position apparently in response to decreased sea ice 
in this area. This change in distribution has corresponded with a 
decrease in seal numbers (T. Haug, pers. comm. 2005). Laidre et al. (in 
press) concluded that harp and hooded seals will be susceptible to 
negative effects associated with reduced sea ice because they whelp in 
large numbers at high density with a high degree of fidelity to 
traditional and critical whelping locations. Because polar bears prey 
primarily on seal species whose reproductive success is closely linked 
to the availability of stable, spring ice, the productivity of these 
species, and, therefore, prey availability for polar bears, is expected 
to decline in response to continued declines in the extent and duration 
of sea ice.

Reduced Prey Availability

    Current evidence suggests that prey availability to polar bears 
will be altered due to reduced prey abundance, changes in prey 
distribution, and changes in sea ice availability as a platform for 
hunting seals (Derocher et al. 2004, pp. 167-169). Young, immature 
bears may be particularly vulnerable to changes in prey availability. 
Polar bears feed preferentially on blubber, and adult bears often leave 
much of a kill behind (Stirling and McEwan 1975, p. 1,021). Younger 
bears, which are not as efficient at taking seals, are known to utilize 
these kills to supplement their diet (Derocher et al. 2004, p. 168). 
Younger bears may be disproportionately impacted if there are fewer 
kills or greater consumption of kills by adults, resulting in less prey 
to scavenge (Derocher et al. 2004, pp. 167-168). Altered prey 
distribution would also likely lead to increased competition for prey 
between dominant and subordinate bears, resulting in subordinate or 
subadult bears having reduced access to prey (Derocher et al. 2004, p. 
167). Thus, a decrease in prey abundance and availability would likely 
result in a concomitant effect to polar bears.
    Reduction in food resources available to seals, in addition to the 
previously discussed effects on reproduction, could affect seal 
abundance and availability as a prey resource to polar bears. Ringed 
seals are generalist feeders but depend on Arctic cod (Boreogadus 
saida) as a major component of their diet (Lowry et al. 1980, p. 2,254; 
Bradstreet and Cross 1982, p. 3; Welch et al. 1997, p. 1,106; Weslawski 
et al. 1994, p. 109). Klumov (1937) regarded Arctic cod as the 
'biological pivot' for many northern marine vertebrates, and as an 
important intermediary link in the food chain. Arctic cod are strongly 
associated with sea ice throughout their range and use the underside of 
the ice to escape from predators (Bradstreet and Cross 1982, p. 39; 
Craig et al. 1982, p. 395; Sekerak 1982, p. 75). While interrelated 
changes in the Arctic food web and effects to upper level consumers are 
difficult to predict, a decrease in seasonal ice cover could negatively 
affect Arctic cod (Tynan and DeMaster 1997, p. 314; Gaston et al. 2003, 
p. 231). Though decreased ice could improve the ability of ringed seals 
to access and prey upon Arctic cod in open water, this change would 
come at increased costs for pups that are forced into the water at an 
earlier age and at risk of predation and thermal challenges (Smith and 
Harwood 2001). For example, studies have shown that even in the 
presence of abundant prey, growth and condition of ringed seals 
continued to be negatively affected by earlier ice break-up (Harwood et 
al. 2000, p. 422). Ice seals, including the ringed seal, are vulnerable 
to habitat loss from changes in the extent or concentration of Arctic 
ice because they depend on pack-ice habitat for pupping, foraging, 
molting, and resting (Tynan and DeMaster 1997, p. 312; Derocher et al. 
2004, p. 168).
    Sea ice is an essential platform that allows polar bears to access 
their prey. The importance of sea ice to polar bear foraging is 
supported by documented relationships between the duration and extent 
of sea ice and polar bear condition, reproduction, and survival that 
are apparent across decades, despite likely fluctuations in ringed seal 
abundance (Stirling et al. 1999, p. 294; Regehr et al. 2007a; p. 2,673; 
Regehr et al. 2007b, p. 18; Rode et al. 2007, p. 6-8). Ferguson et al. 
(2000b, p. 770) reported that higher seal density in Baffin Bay in 
comparison to the Arctic Archipelago did not correspond with a higher 
density of polar bears as a result of the more variable ice conditions 
that occur there. These results emphasize the dependence of polar bears 
on sea ice as a means of accessing prey. Not only does ice have to be 
present over areas of abundant prey, but the physical characteristics 
of sea ice appear to also be important. Stirling et al. (2008, in 
press) noted that unusually rough and rafted sea ice in the 
southeastern Beaufort Sea from about Atkinson Point to the Alaska 
border during the springs of 2004-2006 resulted in reduced hunting 
success of polar bears seeking seals despite extensive searching for 
prey. Thus, transitory or localized increases in prey abundance will 
have no benefit for polar bears if these changes are accompanied by a 
reduction in ice habitat or changes in physical characteristics of ice 
habitat that negate its value for hunting or accessing seals. 
Observations-to-date and projections of future ice conditions support 
the conclusion that accessibility of prey to polar bears is likely to 
decline.

Adaptation

    Animals can adapt to changing environmental conditions principally 
through behavioral plasticity or as a result of natural selection. 
Behavioral

[[Page 28261]]

changes allow adaptation over shorter timeframes and can complement and 
be a precursor to the forces of natural selection that allow animals to 
evolve to better fit new or changed environmental patterns. Unlike 
behavioral plasticity, natural selection is a multi-generational 
response to changing conditions, and its speed is dependent upon the 
organism's degree of genetic variation and generation time and the rate 
of environmental change (Burger and Lynch 1995, p. 161). While some 
short-lived species have exhibited micro-evolutionary responses to 
climate change (e.g., red squirrels (Reale et al. 2003, p. 594)), the 
relatively long generation time (Amstrup 2003, pp. 599-600) and low 
genetic variation of polar bears (Amstrup 2003, p. 590) combined with 
the relatively rapid rate of predicted sea ice changes that are 
expected (Comiso 2006, p. 72; Serreze et al. 2007, p. 1,533-1,536; 
Stroeve et al. 2007, pp. 1-5; Hegerl et al. 2007, p. 716), suggest that 
adaptation through natural selection will be limited for polar bears 
(Stirling and Derocher 1990, p. 201). Furthermore, several recent 
reviews of species adaptation to changing climate suggest that rather 
than evolving, species appear to first alter their geographic 
distribution (Walther et al. 2002, p. 390; Parmesan 2006, p. 655). For 
example, evidence suggests that altered species distribution was the 
mechanism allowing many species to survive during the Pleistocene 
warming period (Parmesan 2006, p. 655). Because polar bears already 
occur in cold extreme climates, they are constrained from responding to 
climate change by significantly altering their distribution (Parmesan 
2006, p. 653). Furthermore, a number of physiological and physical 
characteristics of polar bears constrain their ability to adapt 
behaviorally to rapid and extensive alteration of their sea-ice 
habitat.
    Bears as a genus display a high degree of behavioral plasticity 
(Stirling and Derocher 1990, p. 189), opportunistic feeding strategies 
(Lunn and Stirling 1985, p. 2295; Schwartz et al. 2003, p. 568), and 
physiological mechanisms for energy conservation (Derocher et al. 1990, 
p. 196; McNab 2002, p. 385). However, polar bears evolved to be the 
largest of the bear species (Amstrup 2003, p. 588) by specializing on a 
calorically dense, carnivorous diet that differs from all other bear 
species. Their large size has the advantage of both increased fat 
storage capability (McNab 2002, p. 383) and reduced surface-area to 
volume ratios that minimize heat loss in the Arctic environment (McNab 
2002, pp. 102-103). Because reproduction in polar bears and other bears 
is dependent upon achieving sufficient body mass (Atkinson and Ramsay 
1995, p. 559; Derocher and Stirling 1996, p. 1,246; Derocher and 
Stirling 1998, p. 253), population density is directly linked to the 
availability of high-quality food and primary productivity (Hilderbrand 
et al. 1999, p. 135; Ferguson and McLoughlin 2000, p. 196). Thus, 
maintenance of a high caloric intake is facilitated by the high fat 
content of seals, which is required to maintain polar bears at the body 
size and in the numbers in which they exist today.
    The most recent population estimates of ringed seals, the preferred 
prey of most polar bear populations, range to about 4 million or more, 
making them one of the most abundant seal species in the world 
(Kingsley 1990, p. 140). Rather than switching to alternative prey 
items when ringed seal populations decline as a result of environmental 
conditions, several studies demonstrated corresponding declines in 
polar bear abundance (Stirling and [Oslash]ritsland 1995, p. 2,594; 
Stirling 2002, p. 68). For those polar bear populations that have been 
shown to utilize alternative prey species in response to changing 
availability, such shifts have been among other ice-dependent pinnipeds 
(Derocher et al. 2002, p. 448; Stirling 2002, p. 67; Iverson et al. 
2006, pp. 110-112). For example, Stirling and Parkinson (2006, p. 270) 
and Iverson et al. (2006, p. 112) have shown that polar bears in the 
Davis Strait region have taken advantage of increases in availability 
of harp and hooded seals. See also the section ``Effects of Sea Ice 
Habitat Changes on Polar Bear Prey.'' However, harp and hooded seals 
have historically occurred in areas not frequented by polar bears, and 
are extremely vulnerable to polar bear predation and in Davis Strait 
survival of juveniles is believed to have declined in recent years due 
to significant and rapid reduction in sea ice in the spring (Stirling 
and Parkinson 2006, p. 270).
    Changes in ringed seal distribution and abundance in response to 
changing ice conditions and the ability of polar bears to respond to 
those changes will likely be the most important factor determining 
effects on polar bear populations. Currently, access to ringed seals is 
seasonal for most polar bear populations, resulting in cycles of weight 
gain and weight loss. The most important foraging periods occur during 
the spring, early summer, and following the open-water period in the 
fall (Stirling et al. 1999, p. 303; Derocher et al. 2002, p. 449; 
Durner et al. 2004, pp. 18-19). Because observed and predicted changes 
in sea ice are most dramatic during the summer/fall period (Lemke et 
al. 2007, p. 351; Serreze et al. 2007, p. 1,533-1,536), this is the 
timeframe with the greatest potential for reduced access to ringed 
seals as prey. Most POLAR BEAR POPULATIONs forage minimally during the 
fall open-water period, but a reduction in sea ice can extend the time 
period in which bears have minimal or no access to prey (Stirling et 
al. 1999, p. 299). The effects of a lengthened ice-free season during 
this time period have been associated with declines in polar bear 
condition (Stirling et al. 1999, p. 304; Rode et al. 2007, p. 8), 
reproduction (Regehr et al. 2006; Rode et al. 2007, p. 8-9), survival 
(Regehr et al. 2007a, p. 2,677-2,678; Regehr et al 2007b, p. 13) and 
population size (Regehr et al. 2007a, p. 2,678-2,679;).
    Marine mammal carcasses do not currently constitute a large portion 
of polar bear diets and are unlikely to contribute substantially to 
future diets of polar bears. Although marine mammal carcass 
availability occasionally is predictable where whales are harvested for 
subsistence by Native people (Miller et al. 2006, p. 1) or where 
walruses haul out on land and are killed in stampeding events (Kochnev 
2006, p. 159), in most cases scavenging opportunities are unpredictable 
and not a substitute for normal foraging by polar bears. Even where 
their distribution is predictable, marine mammal carcasses are 
presently used by only a small proportion of most populations or 
contribute minimally to total diet (Bentzen 2006, p. 23; Iverson et al. 
2006, p. 111), and do not appear to be a preferred substitute for the 
normal diet. For example, on the Alaskan Southern Beaufort Sea coast, 
from 2002-2004, on average less than 5 percent of the estimated 
population size of 1,500 polar bears visited subsistence-harvested 
whale carcasses (Miller et al. 2006, p. 9). A small fraction of 
collared pregnant adult females visited whale harvest sites (Fischbach 
et al. 2007, pp. 1,401-1,402). Quotas on subsistence whale harvest 
preclude the possibility that carcasses will be increasingly available 
in the future. Similarly, while walrus contributed up to 24 percent of 
diets of a few individual bears in Davis Strait, population wide, 
walruses composed a small fraction of the total diet (Iverson et al. 
2006, p. 112). Less predictable sea-ice conditions could increase the 
frequency of future marine mammal strandings (Derocher et al. 2004, p. 
89), and some polar bears may benefit from such increases in marine

[[Page 28262]]

mammal mortality. However, if stranding events become frequent, they 
are likely to result in declines of source populations. Thus, the 
likelihood of polar bears relying heavily on stranded or harvested 
marine mammals as a food source is low.
    The potential for polar bears to substitute terrestrial food 
resources in place of their current diet of marine mammals is limited 
by the low quality and availability of foods in most northern 
terrestrial environments. Although smaller bears can maintain their 
body weight consuming diets consisting largely of berries and 
vegetation, low digestibility (Pritchard and Robbins 1990, p. 1,645), 
physical constraints on intake rate, and in the case of berries, low 
protein content, prevent larger bears from similarly subsisting on 
vegetative resources (Stirling and Derocher 1990, p. 191; Rode and 
Robbins 2000, p. 1,640; Rode et al. 2001, p. 70; Welch et al. 1997, p. 
1,105). While some meat sources are available in terrestrial Arctic 
habitats, such as caribou, muskox, and Arctic char, the relative 
scarcity of these resources results in these areas supporting some of 
the smallest grizzly bears in the world at some of the lowest densities 
of any bear populations (Hilderbrand et al. 1999, p. 135; Miller et al. 
1997, p. 37). Lunn and Stirling (1985, p. 2,295) suggest that predation 
on terrestrially-based prey by polar bears may be rare due to the high 
energetic cost of locomotion in polar bears in comparison to grizzly 
bears (Best 1982, p. 63). Energy expended to pursue terrestrial prey 
could exceed the amount of energy obtained. Furthermore, terrestrial 
meat resources are primarily composed of protein and carbohydrates that 
provide approximately half as many calories per gram as fats (Robbins 
1993, p. 10). Because the wet weight of ringed seals is composed of up 
to 50 percent fat (Stirling 2002, p. 67), they provide a substantially 
higher caloric value in comparison to terrestrial foods. Physiological 
and environmental limitations, therefore, preclude the possibility that 
terrestrial food sources alone or as a large portion of the diet would 
be an equivalent substitute for the high fat diet supporting the 
population densities and body size of present-day polar bear 
populations.
    An alternative to maintaining caloric intake would be for polar 
bears to adopt behavioral strategies that reduce energy expenditure and 
requirements. Across populations, polar bears do appear to alter home 
range size and daily travel distances in response to varying levels of 
prey density (Ferguson et al. 2001, p. 51). Additionally, polar bears 
exhibit a variety of patterns of fasting and feeding throughout their 
range, including 3-to 8-month-long fasts, denning by pregnant females, 
and moving between a fasting and a feeding metabolism based on 
continuously changing food availability throughout the year (Derocher 
et al. 1990, p. 202). These physiological and behavioral strategies 
have occurred in response to regional variation in environmental 
conditions but have limitations relative to their application across 
all regions and habitats. Both the long fasts that occur in Western 
Hudson Bay and denning of females throughout polar bear ranges are 
dependent on prey availability that allows sufficient accumulation of 
body fat to survive fasting periods (Derocher and Stirling 1995, p. 
535). The 3-to 8-month-long periods of food deprivation exhibited by 
bears in the southern reaches of their range are supported by a rich 
marine environment that allows spring weight gains sufficient to 
sustain extended summer fasts. In the southern Beaufort Sea, for 
example, the heaviest polar bears were observed during autumn (Durner 
and Amstrup 1996, p. 483). In the Beaufort Sea and other regions of the 
polar basin, the probability that polar bears could survive extended 
summer fasting periods appears to be low. The documented reduction in 
polar bear condition in Western Hudson Bay associated with the recent 
lengthening of the ice-free season (Stirling et al. 1999, p. 294) 
suggests that even in the productive Hudson Bay environment there are 
limits to the ability of polar bears to fast.
    Any period of fasting, whether while denning or resting onshore, 
would require an increase in food availability during alternative, non-
fasting periods for fat accumulation. Adequate food may not be 
available to support sex and age classes other than pregnant females to 
adopt a strategy of denning over extended periods of time during food 
shortage. Furthermore, the ability to take advantage of seasonally 
fluctuating food availability and avoid extended torpor and associated 
physiological costs (Humphries et al. 2003, p. 165) has allowed polar 
bears to maximize access to food resources and is an important factor 
contributing to their large size.
    The known current physiological and physical characteristics of 
polar bears suggest that behavioral adaptation will be sufficiently 
constrained to cause a pronounced reduction in polar bear distribution, 
and abundance, as a result of declining sea ice. The pace at which ice 
conditions are changing and the long generation time of polar bears 
precludes adaptation of new physiological mechanisms and physical 
characteristics through natural selection. Current evidence opposes the 
likelihood that extended periods of torpor, consumption of terrestrial 
foods, or capture of seals in open water will be sufficient mechanisms 
to counter the loss of ice as a platform for hunting seals. Polar bear 
survival and maintenance at sustainable population sizes depends on 
large and accessible seal populations and vast areas of ice from which 
to hunt.

Open Water Habitat

    While sea ice is considered essential habitat for polar bear life 
functions because of the importance for feeding, reproduction, or 
resting, open water is not. Vast areas of open water can present a 
barrier or hazard under certain circumstances for polar bears to access 
sea ice or land. Diminished sea ice cover will increase the energetic 
cost to polar bears for travel, and will increase the risk of drowning 
that may occur during long distance swimming or swimming under 
unfavorable weather conditions. In addition, diminished sea ice cover 
may result in hypothermia for young cubs that are forced to swim for 
longer periods than at present. Under diminishing sea ice projections 
(IPCC 2001, p. 489; ACIA 2005, p. 192; Serreze 2006), ice-dependent 
seals, the principal prey of polar bears, will also be affected through 
distribution changes and reductions in productivity that will 
ultimately translate into reductions in seal population size.

Reduced Hunting Success

    Polar bears are capable of swimming great distances, but exhibit a 
strong preference for sea ice (Mauritzen et al. 2003b, pp. 119-120). 
However, polar bears will also quickly abandon sea ice for land once 
the sea ice concentration drops below 50 percent. This is likely due to 
reduced hunting success in broken ice with significant open water 
(Derocher et al. 2004, p. 167; Stirling et al. 1999, pp. 302-303). 
Bears have only rarely been reported to capture ringed seals in open 
water (Furnell and Oolooyuk 1980, p. 88), therefore, hunting in ice-
free water would not compensate for the corresponding loss of sea ice 
and the access sea ice affords polar bears to hunt ringed seals 
(Stirling and Derocher 1993, p. 241; Derocher et al. 2004, p. 167).
    Reduction in sea ice and corresponding increase in open water would 
likely result in a net reduction in ringed and bearded seals, and 
Pacific walrus abundance (ACIA 2005, p. 510), as well as a reduction in 
ribbon and spotted seals (Born 2005a). While harp

[[Page 28263]]

and hooded seals may change their distribution and temporarily serve as 
alternative prey for polar bears, it appears that these species cannot 
successfully redistribute in a rapidly changing environment and 
reproduce and survive at former levels. Furthermore, a recent study 
suggests that these two species will be the most vulnerable to effects 
of changing ice conditions (Laidre et al. in press). Loss of southern 
pupping areas due to inadequate or highly variable ice conditions will, 
in the long run, also serve to reduce these species as a potential 
polar bear prey (Derocher et al. 2004, p. 168). That increased take of 
other species such as bearded seals, walrus, harbor seals, or harp and 
hooded seals, if they were available, would not likely compensate for 
reduced availability of ringed seals (Derocher et al. 2004, p. 168).

Open Water Swimming

    Open water is considered to present a potential hazard to polar 
bears because it can result in long distances that must be crossed to 
access sea ice or land habitat. In September 2004, four polar bears 
drowned in open water while attempting to swim in an area between shore 
and distant ice (Monnett and Gleason 2006, p. 5). Seas during this 
period were rough, and extensive areas of open water persisted between 
pack ice and land. Because the survey area covered 11 percent of the 
study area, an extrapolation of the survey data to the entire study 
area suggests that a larger number of bears may have drowned during 
this event. Mortalities due to offshore swimming during years when sea 
ice formation nearshore is delayed (or mild) may also be an important 
and unaccounted source of natural mortality given energetic demands 
placed on individual bears engaged in long-distance swimming (Monnett 
and Gleason 2006, p. 6). This suggests that drowning related deaths of 
polar bears may increase in the future if the observed trend of 
recession of pack ice with longer open-water periods continues. 
However, this phenomenon may be shortlived if natural selection 
operates against the behavioral inclination to swim between ice and 
land and favors bears that remain on land or on ice.
    Wave height (sea state) increases as a function of the amount of 
open water surface area. Thus ice reduction not only increases areas of 
open water across which polar bears must swim, but may have an 
influence on the size of wave action. Considered together, these may 
result in increases in bear mortality associated with swimming when 
there is little sea ice to buffer wave action (Monnett and Gleason 
2006, p. 5). Evidence of such mortality was also reported east of 
Svalbard in 2006, where one exhausted and one apparently dead polar 
bear were stranded ( J. Dowdeswell, Head of the Scott Polar Research 
Institute of England, pers. obs.).

Terrestrial Habitat

    Although sea ice is the polar bear's principal habitat, terrestrial 
habitat serves a vital function seasonally for maternal denning. In 
addition, use of terrestrial habitat is seasonally important for 
resting and feeding in the absence of suitable sea ice. Due to 
retreating sea ice, polar bears may be forced to make increased use of 
land in future years. The following sections describe the effects or 
potential effects of climate change and other factors on polar bear use 
of terrestrial habitat. One section focuses on access to or changes in 
the quality of denning habitat, and one focuses on distribution changes 
and corresponding increases in polar bear-human interactions in coastal 
areas. Also discussed are the potential consequences of and potential 
concerns for development, primarily oil and gas exploration and 
production which occur in polar bear habitat (both marine and 
terrestrial).

Access to and Alteration of Denning Areas

    Many female polar bears repeatedly return to specific denning areas 
on land (Harrington 1968, p. 11; Schweinsburg et al. 1984, p. 169; 
Garner et al. 1994, p. 401; Ramsay and Stirling 1990, p. 233; Amstrup 
and Gardner 1995, p. 8). For bears to access preferred denning areas, 
pack ice must drift close enough or must freeze sufficiently early in 
the fall to allow pregnant females to walk or swim to the area by late 
October or early November (Derocher et al. 2004, p. 166), although 
polar bears may den into early December (Amstrup 2003, p. 597). 
Stirling and Andriashek (1992, p. 364) found that the distribution of 
polar bear maternal dens on land was related to the proximity of 
persistent summer sea ice, or areas that develop sea ice early in the 
autumn.
    Derocher et al. (2004, p. 166) predicted that under future climate 
change scenarios, pregnant female polar bears will likely be unable to 
reach many of the most important denning areas in the Svalbard 
Archipelago, Franz Josef Land, Novaya Zemlya, Wrangel Island, Hudson 
Bay, and the Arctic National Wildlife Refuge and north coast of the 
Beaufort Sea (see Figure 8). Under likely climate change scenarios, the 
distance between the edge of the pack ice and land will increase (ACIA 
2005, pp. 456-459). As distance increases between the southern edge of 
the pack ice and coastal denning areas, it will become increasingly 
difficult for females to access preferred denning locations. In 
addition to suitable access and availability of den sites, body 
condition is an important prerequisite for cub survival, and 
recruitment into the population as pregnant bears with low lipid stores 
are less likely to leave the den with healthy young in the spring 
(Atkinson and Ramsay 1995, pp. 565-566). Messier et al. (1994) 
postulated that pregnant bears may reduce activity levels up to 2 
months prior to denning to conserve energy.

[[Page 28264]]

[GRAPHIC] [TIFF OMITTED] TR15MY08.010

    Bergen et al. (2007, p. 2) hypothesized that denning success is 
inversely related to the distance a pregnant polar bear must travel to 
reach denning habitat. These authors developed an approach using 
observed sea ice distributions (1979-2006) and GCM-derived sea ice 
projections (1975-2060) to estimate minimum distances that pregnant 
polar bears would have to travel between summer sea ice habitats and a 
terrestrial den location in northeast Alaska (Bergen et al. 2007, p. 2-
3). In this pilot assessment, calculations were made with and without 
the constraint of least cost movement paths, which required bears to 
optimally follow high-quality sea ice habitats. Although variation was 
evident and considerable among the five GCMs analyzed, the smoothed 
multi-model average distances aligned well with those derived from the 
observational record. The authors found that between 1979 and 2006, the 
minimum distance polar bears traveled to denning habitats in northeast 
Alaska increased at an average linear rate of 6-8 km per year (3.7-5.0 
mi per year), and almost doubled after 1992. They projected that travel 
would increase threefold by 2060 (Bergen et al. 2007, p. 2-3).
    Based on projected retraction of sea ice in the future, Bergen et 
al. (2007, p. 2) states, ``thus, pregnant polar bears will likely incur 
greater energetic expense in reaching traditional denning regions if 
sea ice loss continues along the projected trajectory.'' Increased 
travel distances could negatively affect individual fitness, denning 
success, and ultimately populations of polar bears (Aars et al. 2006). 
While the Bergen et al. (2007, p. 2) study focused on polar bears using 
denning habitat in northern Alaska, other denning regions in the 
Arctic, particularly within the polar basin region, are much farther 
from

[[Page 28265]]

areas where summer ice is predicted to persist in the future. Polar 
bears returning to other denning locales, such as Wrangel Island or the 
Chukotka Peninsula, will likely have to travel greater distances than 
those reported here. Most high-density denning areas are located at 
more southerly latitudes (see Figure 8). For populations that den at 
high latitudes in the Canadian archipelago islands, access to, and 
availability of, suitable den sites may not currently be a problem. 
However, access to historically-used den sites in the future may become 
more problematic in the northern areas. The degree to which polar bears 
may use nontraditional denning habitats at higher latitudes in the 
future, through facultative adaptation, is largely unknown but is 
possible.
    Climate change could also impact populations where females den in 
snow (Derocher et al. 2004). Insufficient snow would prevent den 
construction or result in use of poor sites where the roof could 
collapse (Derocher et al. 2004). Too much snow could necessitate the 
reconfiguration of the den by the female throughout the winter 
(Derocher et al. 2004). Changes in amount and timing of snowfall could 
also impact the thermal properties of the dens (Derocher et al. 2004). 
Since polar bear cubs are born helpless and need to nurse for three 
months before emerging from the den, major changes in the thermal 
properties of dens could negatively impact cub survival (Derocher et 
al. 2004). Finally, unusual rain events are projected to increase 
throughout the Arctic in winter (ACIA 2005), and increased rain in late 
winter and early spring could cause den collapse (Stirling and Smith 
2004). Den collapse following a warming period was observed in the 
Beaufort Sea and resulted in the death of a mother and her two young 
cubs (Clarkson and Irish 1991). After March 1990 brought unseasonable 
rain south of Churchill, Manitoba, Canada, researchers observed large 
snow banks along creeks and rivers used for denning that had collapsed 
because of the weight of the wet snow, and noted that had there been 
maternity dens in this area the bears likely would have been crushed 
(Stirling and Derocher 1993).

Oil and Gas Exploration, Development, and Production

    Each of the Parties to the 1973 Polar Bear Agreement (see 
International Agreements and Oversight section below) has developed 
detailed regulations pertaining to the extraction of oil and gas within 
their countries. The greatest level of oil and gas activity within 
polar bear habitat is currently occurring in the United States 
(Alaska). Exploration and production activities are also actively 
underway in Russia, Canada, Norway, and Denmark (Greenland). In the 
United States, all such leasing and production activities are evaluated 
as specified by the National Environmental Policy Act (42 U.S.C. 4321 
et seq.) (NEPA), Outer Continental Shelf Lands Act (43 U.S.C. 1331 et 
seq.) (OCSLA), and numerous other statutes, that evaluate and guide 
exploration, development, and production in order to minimize possible 
environmental impacts. In Alaska, the majority of oil and gas 
development is on land; however, some offshore production sites have 
been developed, and others are planned.
    Historically, oil and gas activities have resulted in little direct 
mortality to polar bears, and that mortality which has occurred has 
been associated with human-bear interactions as opposed to a spill 
event. However, oil and gas activities are increasing as development 
continues to expand throughout the U.S. Arctic and internationally, 
including in polar bear terrestrial and marine habitats. The greatest 
concern for future oil and gas development is the effect of an oil 
spill or discharges in the marine environment impacting polar bears or 
their habitat. Disturbance from activities associated with oil and gas 
activities can result in direct or indirect effects on polar bear use 
of habitat. Direct disturbances include displacement of bears or their 
primary prey (ringed and bearded seals) due to the movement of 
equipment, personnel, and ships through polar bear habitat. Female 
polar bears tend to select secluded areas for denning, presumably to 
minimize disturbance during the critical period of cub development. 
Direct disturbance may cause abandonment of established dens before 
their cubs are ready to leave. For example, expansion of the network of 
roads, pipelines, well pads, and infrastructure associated with oil and 
gas activities may force pregnant females into marginal denning 
locations (Lentfer and Hensel 1980, p. 106; Amstrup et al. 1986, p. 
242). The potential effects of human activities are much greater in 
areas where there is a high concentration of dens such as Wrangel 
Island. Although bear behavior is highly variable among individuals and 
the sample size was small, Amstrup (1993, pp. 247-249) found that in 
some instances denning bears were fairly tolerant to some levels of 
activity. Increased shipping may increase the amount of open water, 
cause disturbance to polar bears and their prey, and increase the 
potential for additional oil spills (Granier et al. 2006 p. 4). Much of 
the North Slope of Alaska contains habitat suitable for polar bear 
denning (Durner et al. 2001, p. 119). Furthermore, in northern Alaska 
and Chukotka, Russia, polar bears appear to be using land areas with 
greater frequency during the season of minimum sea ice. Some of these 
areas coincide with areas that have traditionally been used for oil and 
gas production and exploration. These events increase the potential for 
interactions with humans (Durner et al. 2001, p. 115; National Research 
Council (NRC) 2003, p. 168); however, current regulations minimize 
these interactions by establishing buffer zones around active den 
sites.
    The National Research Council (NRC 2003, p. 169) evaluated the 
cumulative effects of oil and gas development in Alaska and concluded 
the following related to polar bears and ringed seals:
     ``Industrial activity in the marine waters of the Beaufort 
Sea has been limited and sporadic and likely has not caused serious 
cumulative effects to ringed seals or polar bears.
     Careful mitigation can help to reduce the effects of oil 
and gas development and their accumulation, especially if there are no 
major oil spills. However, the effects of full-scale industrial 
development of waters off the North Slope would accumulate through the 
displacement of polar bears and ringed seals from their habitats, 
increased mortality, and decreased reproductive success.
     A major Beaufort Sea oil spill would have major effects on 
polar bears and ringed seals.
     Climatic warming at predicted rates in the Beaufort Sea 
region is likely to have serious consequences for ringed seals and 
polar bears, and those effects will accumulate with the effects of oil 
and gas activities in the region.
     Unless studies to address the potential accumulation of 
effects on North Slope polar bears or ringed seals are designed, 
funded, and conducted over long periods of time, it will be impossible 
to verify whether such effects occur, to measure them, or to explain 
their causes.''
    Some alteration of polar bear habitat has occurred from oil and gas 
development, seismic exploration, or other activities in denning areas, 
and potential oil spills in the marine environment and expanded 
activities increase the potential for additional alteration. Any such 
impacts would be additive to other factors already or potentially 
affecting polar bears and their habitat. However, mitigative 
regulations that have been instituted,

[[Page 28266]]

and will be modified as necessary, have proven to be highly successful 
in providing for polar bear conservation in Alaska.
    Oil and gas exploration, development, and production activities do 
not threaten the species throughout all or a significant portion of its 
range based on: (1) mitigation measures in place now and likely to be 
used in the future; (2) historical information on the level of oil and 
gas development activities occurring within polar bear habitat within 
the Arctic; (3) the lack of direct quantifiable impacts to polar bear 
habitat from these activities noted to date in Alaska; (4) the current 
availability of suitable alternative habitat; and (5) the limited and 
localized nature of the development activities, or possible events, 
such as oil spills.
    Documented direct impacts on polar bears by the oil and gas 
industry during the past 30 years are minimal. Polar bears spend a 
limited amount of time on land, particularly in the southern Beaufort 
Sea, coming ashore to feed, den, or move to other areas. At times, fall 
storms deposit bears along the coastline where bears remain until the 
ice returns. For this reason, polar bears have mainly been encountered 
at or near most coastal and offshore production facilities, or along 
the roads and causeways that link these facilities to the mainland. 
During those periods, the likelihood of incidental interactions between 
polar bears and industry activities increases. As discussed under our 
Factor D analysis below, the MMPA has specific provisions for such 
incidental take, including specific findings that must be made by the 
Service and the provision of mitigation actions, which serve to 
minimize the likelihood of impacts upon polar bears. We have found that 
the polar bear interaction planning and training requirements set forth 
in the incidental take regulations and required through the letters of 
authorization (LOA) process, and the overall review of the regulations 
every one to five years has increased polar bear awareness and 
minimized these encounters in the United States. The LOA requirements 
have also increased our knowledge of polar bear activity in the 
developed areas.
    Prior to issuance of regulations, lethal takes by industry were 
rare. Since 1968, there have been two documented cases of lethal take 
of polar bears associated with oil and gas activities. In both 
instances, the lethal take was reported to be in defense of human life. 
In the winter of 1968-1969, an industry employee shot and killed a 
polar bear (Brooks et al. 1971, p. 15). In 1990, a female polar bear 
was killed at a drill site on the west side of Camden Bay (USFWS 
internal correspondence, 1990). In contrast, 33 polar bears were killed 
in the Canadian Northwest Territories from 1976 to 1986 due to 
encounters with industry (Stenhouse et al. 1988, p. 276). Since the 
beginning of the incidental take program, which includes requirements 
for monitoring, project design, and hazing of bears presenting a safety 
problem, no polar bears have been killed due to encounters associated 
with the current industry activities on the North Slope of Alaska.

Observed Demographic Effects of Sea Ice Changes on Polar Bear

    The potential demographic effects of sea ice changes on polar bear 
reproductive and survival rates (vital rates) and ultimately on 
population size are difficult to quantify due to the need for extensive 
time series of data. This is especially true for a long-lived and 
widely dispersed species like the polar bear. Recent research by 
Stirling et al. (2006), Regehr et al. (2007a, b), Hunter et al. (2007), 
and Rode et al. (2007), however, evaluates these important 
relationships and adds significantly to our understanding of how and to 
what extent environmental changes influence essential life history 
parameters. The key demographic factors for polar bears are physical 
condition, reproduction, and survival. Alteration of these 
characteristics has been associated with elevated risks of extinction 
for other species (McKinney 1997, p. 496; Beissinger 2000, p. 11,688; 
Owens and Bennett 2000, p. 12,145).
    Physical condition of polar bears determines the welfare of 
individuals, and, ultimately, through their reproduction and survival, 
the welfare of populations (Stirling et al. 1999, p. 304; Regehr et al. 
2007a, p. 13; Regehr et al 2007b, pp. 2,677-2,680; Hunter et al. 2007, 
pp. 8-13). In general, Derocher et al. (2004, p. 170) predict that 
declines in the physical condition will initially affect female 
reproductive rates and juvenile survival and then under more severe 
conditions adult female survival rates. Adult females represent the 
most important sex and age class within the population regarding 
population status (Taylor et al. 1987, p. 811).
    Declines in fat reserves during critical times in the polar bear 
life cycle detrimentally affect populations through delay in the age of 
first reproduction, decrease in denning success, decline in litter 
sizes with more single cub litters and fewer cubs, and lower cub body 
weights and lower survival rates (Atkinson and Ramsay 1995, pp. 565-
566; Derocher et al. 2004, p. 170). Derocher and Stirling (1998, pp. 
255-256) demonstrated that body mass of adult females is correlated 
with cub mass at den emergence, with heavier females producing heavier 
cubs and lighter females producing lighter cubs. Heavier cubs have a 
higher rate of survival (Derocher and Stirling 1996, p. 1,249). A 
higher proportion of females in poor condition do not initiate denning 
or are likely to abandon their den and cub(s) mid-winter (Derocher et 
al. 2004, p. 170). Females with insufficient fat stores or in poor 
hunting condition in the early spring after den emergence could lead to 
increased cub mortality (Derocher et al. 2004, p. 170). In addition, 
sea ice conditions that include broken or more fragmented ice may 
require young cubs to enter water more frequently and for more 
prolonged periods of time, thus increasing mortality from hypothermia. 
Blix and Lenter (1979, p. 72) and Larsen (1985, p. 325) indicate that 
cubs are unable to survive immersion in icy water for more than 
approximately 10 minutes. This is due to cubs having little insulating 
fat, their fur losing its insulating ability when wet (though the fur 
of adults sheds water and recovers its insulating properties quickly), 
and the core body temperature dropping rapidly when they are immersed 
in icy water (Blix and Lentfer 1979, p. 72).
    Reductions in sea ice, as discussed in previous sections, will 
alter ringed seal distribution, abundance, and availability for polar 
bears. Such reductions will, in turn, decrease polar bear body 
condition (Derocher et al. 2004, p. 165). Derocher et al. (2004, p. 
165) projected that most females in the Western Hudson Bay population 
may be unable to reach the minimum 189 kg (417 lbs) body mass required 
to successfully reproduce by the year 2012. Stirling (Canadian Wildlife 
Service, pers comm. 2006) indicates, based on the decline in weights of 
lone and suspected pregnant females in the fall (Stirling and Parkinson 
2006), that the 2012 date is likely premature. However, Stirling 
(Canadian Wildlife Service, pers comm. 2006) found that the trend of 
continuing weight loss by adult female polar bears in the fall is clear 
and continuing, and, therefore, Stirling believed that the production 
of cubs in these areas will probably be negligible within the next 15-
25 years.
    Furthermore, with the extent of sea ice projected to be 
substantially reduced in the future (e.g., Stroeve et al. 2007, pp. 1-
5), opportunities for increased feeding to recover fat stores during 
the season of minimum ice may be limited

[[Page 28267]]

(Durner et al. 2007, p. 12). It should be noted that the models project 
decreased ice cover in all months in the Arctic, but that (as has been 
observed) the projected changes in the 21st century are largest in 
summer (Holland et al. 2006, pp. 1-5; Stroeve et al. 2007, pp. 1-5; 
Durner et al. 2007, p. 12; DeWeaver 2007, p. 2; IPCC 2007). Mortality 
of polar bears is thought to be the highest in winter when fat stores 
are low and energetic demands are greatest. Pregnant females are in 
dens during this period using fat reserves and not feeding. The 
availability and accessibility of seals to polar bears, which often 
hunt at the breathing holes, is likely to decrease with increasing 
amounts of open water or fragmented ice (Derocher et al. 2004, p. 167).

Demographic Effects on Polar Bear Populations with Long-term Data Sets

    This section summarizes demographic effects on polar bear 
populations for which long-term data sets are available. These 
populations are: Western Hudson Bay, Southern Hudson Bay, Southern 
Beaufort Sea, Northern Beaufort Sea, and, to a lesser extent, Foxe 
Basin, Baffin Bay, Davis Strait, and Eastern Hudson Bay.

Western Hudson Bay

    The Western Hudson Bay polar bear population occurs near the 
southern limit of the species' range and is relatively discrete from 
adjacent populations (Derocher and Stirling 1990, p. 1,390; Stirling et 
al. 2004, p. 16). In winter and spring, polar bears of the Western 
Hudson Bay population disperse over the ice-covered Bay to hunt seals 
(Iverson et al. 2006, p. 98). In summer and autumn, when Hudson Bay is 
ice-free, the population is confined to a restricted area of land on 
the western coast of the Bay. There, nonpregnant polar bears are cut 
off from their seal prey and must rely on fat reserves until freeze-up, 
a period of approximately 4 months. Pregnant bears going into dens may 
be food deprived for up to an additional 4 months (a total of 8 
months).
    In the past 50 years, spring air temperatures in western Hudson Bay 
have increased by 2-3 degrees C (Skinner et al. 1998; Gagnon and Gough 
2005, p. 289). Consequently, the sea ice on the Bay now breaks up 
approximately 3 weeks earlier than it did 30 years ago (Stirling and 
Parkinson 2006, p. 265). This forces the Western Hudson Bay polar bears 
off the sea ice earlier, shortening the spring foraging period when 
seals are most available, and reducing the polar bears' ability to 
accumulate the fat reserves needed to survive while stranded onshore. 
Previous studies have shown a correlation between rising air 
temperatures, earlier sea ice break-up, and declining recruitment and 
body condition for polar bears in western Hudson Bay (Derocher and 
Stirling 1996, p. 1,250; Stirling et al. 1999, p. 294; Stirling and 
Parkinson 2006, p. 266). Based on GCM projections of continued warming 
and progressively earlier sea ice break-up (Zhang and Walsh 2006), 
Stirling and Parkinson (2006, p. 271-272) predicted that conditions 
will become increasingly difficult for the Western Hudson Bay 
population.
    Regehr et al. (2007a, p. 2,673) used capture-recapture models to 
estimate population size and survival for polar bears captured from 
1984 to 2004 along the western coast of Hudson Bay. During this period 
the Western Hudson Bay population experienced a statistically 
significant decline of 22 percent, from 1,194 bears in 1987 to 935 
bears in 2004. Regehr et al. (2007a, p. 2,673) notes that while 
survival of adult female and male bears was stable, survival of 
juvenile, subadult, and senescent (nonreproductive) bears was 
negatively correlated with the spring sea ice break-up date--a date 
that occurred approximately 3 weeks earlier in 2004 than in 1984. Long-
term observations suggest that the Western Hudson Bay population 
continues to exhibit a high degree of fidelity to the study area during 
the early part of the sea ice-free season (Stirling et al. 1977, p. 
1,126; Stirling et al. 1999, p. 301; Taylor and Lee 1995, p. 147), 
which precludes permanent emigration as a cause for the population 
decline. The authors (Regehr et al. 2007a, p. 2,673) attribute the 
decline of the Western Hudson Bay population to increased natural 
mortality associated with earlier sea ice break-up, and the continued 
harvest of approximately 40 polar bears per year (Lunn et al. 2002, p. 
104). No support for alternative explanations was found.

Southern Hudson Bay

    Evidence of declining body condition for polar bears in the Western 
Hudson Bay population suggests that there should be evidence of 
parallel declines in adjacent polar bear populations experiencing 
similar environmental conditions. In an effort to evaluate an adjacent 
population, Obbard et al. (2006, p. 2) conducted an analysis of polar 
bear condition in the Southern Hudson Bay population by comparing body 
condition for two time periods, 1984-1986 and 2000-2005. The authors 
found that the average body condition for all age and reproductive 
classes combined was significantly poorer for Southern Hudson Bay bears 
captured from 2000-2005 than for bears captured from 1984-1986 (Obbard 
et al. 2006, p. 4). The results indicate a declining trend in condition 
for all age and reproductive classes of polar bears since the mid-
1980s. The results further reveal that the decline has been greatest 
for pregnant females and subadult bears--trends that will likely have 
an impact on future reproductive output and subadult survival (Obbard 
et al. 2006, p. 1).
    Obbard et al (2006, p. 4) evaluated inter-annual variability in 
body condition in relation to the timing of ice melt and to duration of 
ice cover in the previous winter and found no significant relationship 
despite strong evidence of a significant trend towards both later 
freeze-up and earlier break-up (Gough et al. 2004, p. 298; Gagnon and 
Gough 2005, p. 293). While southern Hudson Bay loses its sea ice cover 
later in the year than western Hudson Bay, the authors believe that 
other factors or combinations of factors (that likely also include 
later freeze-up and earlier break-up) are operating to affect body 
condition in southern Hudson Bay polar bears. These factors may include 
unusual spring rain events that occur during March or April when ringed 
seals are giving birth to pups in on-ice birthing lairs (Stirling and 
Smith 2004, pp. 60-63), depth of snow accumulation and roughness of the 
ice that vary over time and also affect polar bear hunting success 
(Stirling and Smith 2004, p. 60-62; Ferguson et al. 2005, p. 131), 
changes in the abundance and distribution of ringed seals, and reduced 
pregnancy rates and of reduced pup survival in ringed seals from 
western Hudson Bay during the 1990s (Ferguson et al. 2005, p. 132; 
Stirling 2005, p. 381).
    A more recent status assessment using open population capture-
recapture models was conducted to evaluate population trend in the 
Southern Hudson Bay population (Obbard et al. 2007, pp. 3-9). The 
authors found that the population and survival estimates for subadult 
female and male polar bears were not significantly different between 
1984-1986 and 1999-2005 respectively. There was weak evidence of lower 
survival of cubs, yearlings, and senescent adults in the recent time 
period (Obbard et al. 2007, pp. 10-11). As previously reported, no 
association was apparent between survival and cub-of-the-year body 
condition, average body condition for the age class, or extent of ice 
cover. The authors indicate that lack of association could be real or 
attributable to various factors--the coarse scale of average body 
condition measure, or to limited sample size, or

[[Page 28268]]

limited years of intensive sampling (Obbard et al. 2007, pp. 11-12).
    The decline in survival estimates, although not statistically 
significantly, combined with the evidence of significant declines in 
body condition for all age and sex classes, suggest that the Southern 
Hudson Bay population may be under increased stress at this time 
(Obbard et al. 2007, p. 14). The authors also indicated that if the 
trend in earlier ice break-up and later freeze-up continues in this 
area, it is likely that the population will exhibit changes similar to 
the Western Hudson Bay population even though no current significant 
relationships exist between extent of ice cover and the survival 
estimates and the average body condition for each age class (Obbard et 
al. 2007, p. 14).

Southern Beaufort Sea

    The Southern Beaufort Sea population has also been subject to 
dramatic changes in the sea ice environment, beginning in the winter of 
1989-1990 (Regehr et al. 2006, p. 2). These changes were linked 
initially through direct observation of distribution changes during the 
fall open-water period. With the exception of the Western Hudson Bay 
population, the Southern Beaufort Sea population has the most complete 
and extensive time series of life history data, dating back to the late 
1960s. A 5-year coordinated capture-recapture study of this population 
to evaluate changes in the health and status of polar bears and life 
history parameters such as reproduction, survival, and abundance was 
completed in 2006. Results of this study indicate that the estimated 
population size has gone from 1,800 polar bears (Amstrup et al. 1986, 
p. 244; Amstrup 2000, p. 146) to 1,526 polar bears in 2006 (Regehr et 
al. 2006, p. 16). The precision of the earlier estimate (1,800 polar 
bears) was low, and consequently there is not a statistically 
significant difference between the two point estimates. Amstrup et al. 
(2001, p. 230) provided a population estimate of as many as 2,500 bears 
for this population in the late 1980s, but the statistical variance of 
this estimate could not be calculated and thus precludes the 
comparative value of the estimate.
    Survival rates, weights, and skull sizes were compared for two 
periods of time, 1967-1989 and 1990-2006. In the later period, 
estimates of cub survival declined significantly, from 0.65 to 0.43 
(Regehr et al. 2006, p. 11). Cub weights also decreased slightly. The 
authors believed that poor survival of new cubs may have been related 
to declining physical condition of females entering dens and 
consequently of cubs born during recent years, as reflected by smaller 
skull measurements. In addition, body weights for adult males decreased 
significantly, and skull measurements were reduced since 1990 (Regehr 
et al. 2006, p 1). Because male polar bears continue to grow into their 
teen years (Derocher et al. 2005, p. 898), if nutritional intake was 
similar since 1990, the size of males should have increased (Regehr et 
al. 2006, p. 18). The observed changes reflect a trend toward smaller 
size adult male bears. Although a number of the indices of population 
status were not independently significant, nearly all of the indices 
illustrated a declining trend. In the case of the Western Hudson Bay 
population, declines in cub survival and physical stature were recorded 
for a number of years (Stirling et al. 1999, p. 300; Derocher et al. 
2004, p. 165) before a statistically significant decline in the 
population size was confirmed (Regehr et al. 2007, p. 2,673).
    In further support of the interaction of environmental factors, 
nutritional stress, and their effect on polar bears, several unusual 
mortality events have been documented in the southern Beaufort Sea. 
During the winter and early spring of 2004, three observations of polar 
bear cannibalism were recorded (Amstrup et al. 2006b, p. 1). Similar 
observations had not been recorded in that region despite studies 
extending back for decades. In the fall of 2004, four polar bears were 
observed to have drowned while attempting to swim between shore and 
distant pack ice in the Beaufort Sea. Despite offshore surveys 
extending back to 1987, similar observations had not previously been 
recorded (Monnett and Gleason 2006, p. 3). In spring of 2006, three 
adult female polar bears and one yearling were found dead. Two of these 
females and the yearling had no fat stores and apparently starved to 
death, while the third adult female was too heavily scavenged to 
determine a cause of death. This mortality is suspicious because prime 
age females have had very high survival rates in the past (Amstrup and 
Durner 1995, p. 1,315). Similarly, the yearling that was found starved 
was the offspring of another radio-collared prime age female whose 
collar had failed prior to her yearling being found dead. Annual 
survival of yearlings, given survival of their mother, was previously 
estimated to be 0.86 (Amstrup and Durner 1995, p. 1,316). The 
probability, therefore, that this yearling died while its mother was 
still alive was only approximately 14 percent. Regehr et al. (2006, p. 
27) indicate that these anecdotal observations, in combination with 
changes in survival of young and declines in size and weights reported 
above, suggest mechanisms by which a changing sea ice environment can 
affect polar bear demographics and population status.
    The work by Regehr et al. (2006, pp. 1, 5) described above 
suggested that the physical stature (as measured by skull size and body 
weight data) of some sex and age classes of bears in the Southern 
Beaufort Sea population had changed between early and latter portions 
of this study, but trends in or causes of those changes were not 
investigated. Rode et al. (2007, pp. 1-28), using sea ice and polar 
bear capture data from 1982 to 2006, investigated whether these 
measurements changed over time or in relation to sea ice extent. Annual 
variation in sea ice habitat important to polar bear foraging was 
quantified as the percent of days between April to November when mean 
sea ice concentration over the continental shelf was greater than or 
equal to 50 percent. The 50 percent concentration threshold was used 
because bears make little use of areas where sea ice concentration is 
lower (Durner et al. 2004, p. 19). The April to November period was 
used because it is believed to be the primary foraging period for polar 
bears in the southern Beaufort Sea (Amstrup et al. 2000b, p. 963). The 
frequency of capture events for individual bears was evaluated to 
determine if this factor had an effect on bear size, mass, or 
condition. Rode et al. (2007, pp. 5-8) found that mass, length, skull 
size, and body condition indices (BCI) of growing males (aged 3-10), 
mass and skull size of cubs-of-the year, and the number of yearlings 
per female in the spring and fall were all positively and significantly 
related to the percent of days in which sea ice covered the continental 
shelf. Unlike Regehr et al. (2006, p. 1), Rode et al. (2007, p. 8) did 
not document a declining trend in skull size or body size of cubs-of-
the-year when the date of capture was considered. Condition of adult 
males 11 years and older and of adult females did not decline. There 
was some evidence, based on capture dates, that females with cubs have 
been emerging from dens earlier in recent years. Thus, though cubs were 
smaller in recent years, they also were captured earlier in the year. 
Why females may be emerging from dens earlier than they used to is not 
certain and warrants additional research.
    Skull sizes and/or lengths of adult and subadult males and females 
decreased over time during the study (Rode et al. 2007, p. 1). Adult 
body mass was not related to sea ice cover and did

[[Page 28269]]

not show a trend with time. The condition of adult females exhibited a 
positive trend over time, reflecting a decline in length without a 
parallel trend in mass. Though cub production increased over time, the 
number of cubs-of-the-year per female in the fall and yearlings per 
female in the spring declined (Rode et al. 2007, p. 1), corroborating 
the reduced cub survival, as noted previously by Regehr et al. (2006, 
p. 1). Males exhibited a stronger relationship with sea ice conditions 
and more pronounced declines over time than females. The mean body mass 
of males of ages 3-10 years (63 percent of all males captured over the 
age of 3) declined by 2.2 kg (4.9 lbs) per year, consistent with Regehr 
et al. (2006, p. 1), and was positively related to the percent of days 
with greater than or equal to 50 percent mean ice concentration over 
the continental shelf (Rode et al. 2007, p. 10). Because declines were 
not apparent in older, fully grown males, but were apparent in younger, 
fully grown males, the authors suggest that nutritional limitations may 
have occurred only in more recent years after the time when older males 
in the population were fully grown. Bears with prior capture history 
were either larger or similar in stature and mass to bears captured for 
the first time, indicating that research activities did not influence 
trends in the data.
    The effect of sea ice conditions on the mass and size of subadult 
males suggests that, if sea ice conditions changed over time, this 
factor could be associated with the observed declines in these 
measures. While the sea ice metric used in Rode et al. (2007, p. 3) was 
meaningful to the foraging success of polar bears, recent habitat 
analyses have resulted in improvements in the understanding of 
preferred sea ice conditions of bears in the Southern Beaufort Sea 
population. Durner et al. (2007, pp. 6, 9) recently identified optimal 
polar bear habitat based on bathymetry (water depth), proximity to 
land, sea ice concentration, and distance to sea ice edges using 
resource selection functions. The sum of the monthly extent of this 
optimal habitat for each year within the range of the Southern Beaufort 
Sea population (Amstrup et al. 2004, p. 670) was strongly correlated 
with the Rode et al. (2007, p. 10) sea ice metric for the 1982-2006 
period. This suggests that the Rode et al. (2007, p. 10) sea ice metric 
effectively quantified important habitat value. While the Rode et al. 
(2007, p. 10) sea ice metric did not exhibit a significantly negative 
trend over time, the optimal habitat available to bears in the southern 
Beaufort Sea as identified by Durner et al. (2007, pp. 5-6) did 
significantly decline between 1982 and 2006. This further supports the 
observation that the declining trend in bear size and condition over 
time were associated with a declining trend in availability of foraging 
habitat, particularly for subadult males whose mass and stature were 
related to sea ice conditions.
    Rode et al. (2007, p. 12) concludes that the declines in mass and 
body condition index of subadult males, declines in growth of males and 
females, and declines in cub recruitment and survival suggest that 
polar bears of the Southern Beaufort Sea population have experienced a 
declining trend in nutritional status. The significant relationship 
between several of these measurements and sea ice cover over the 
continental shelf suggests that nutritional limitations may be 
associated with changing sea ice conditions.
    Regehr et al. (2007b, p. 3) used multistate capture-recapture 
models that classified individual polar bears by sex, age, and 
reproductive category to evaluate the effects of declines in the extent 
and duration of sea ice on survival and breeding probabilities for 
polar bears in the Southern Beaufort Sea population. The study 
incorporated data collected from 2001-2006. Key elements of the models 
were the dependence of survival on the duration of the ice-free period 
over the continental shelf in the southern Beaufort Sea region, and 
variation in breeding probabilities over time. Other factors considered 
included harvest mortality, uneven capture probability, and temporary 
emigrations from the study area. Results of Regehr et al. (2007b, p. 1) 
reveal that in 2001 and 2002, the ice-free period was relatively short 
(mean 92 days) and survival of adult female polar bears was high 
(approximately 0.99). In 2004 and 2005, the ice-free period was long 
(mean 135 days) and survival of adult female polar bears was lower 
(approximately 0.77). Breeding and cub-of-the-year litter survival also 
declined from high rates in early years to lower rates in latter years 
of the study. The short duration of the study (5 years) introduced 
uncertainty associated with the logistic relationship between the sea 
ice covariate and survival. However, the most supported noncovariate 
models (i.e., that excluded ice as a covariate) also estimated declines 
in survival and breeding from 2001 to 2005 that were in close agreement 
to the declines estimated by the full model set.
    Although the precision of vital rates estimated by Regehr et al. 
(2007b, pp. 17-18) was low, subsequent analyses (Hunter et al. 2007, p. 
6) indicated that the declines in vital rates associated with longer 
ice-free periods have ramifications for the trend of the Southern 
Beaufort Sea population (i.e., result in a declining population trend). 
The Southern Beaufort Sea population occupies habitats similar to four 
other populations (Chukchi, Laptev, Kara, and Barents Seas) which 
represent over one-third of the world's polar bears. These areas have 
experienced sea ice declines in recent years that have been more severe 
than those experienced in the southern Beaufort Sea (Durner et al. 
2007, pp. 32-33), and declining trends in status for these populations 
are projected to be similar to or greater than those projected for the 
Southern Beaufort Sea population (Amstrup et al. 2007, pp 7-8, 32).

Northern Beaufort Sea

    The Northern Beaufort Sea population, unlike the Southern Beaufort 
Sea and Western Hudson Bay populations, is located in a region where 
sea ice converges on shorelines throughout most of the year. Stirling 
et al. (2007, pp. 1-6) used open population capture-recapture models of 
data collected from 1971-2006 to assess the relationship between polar 
bear survival and sex, age, time period, and a number of environmental 
covariates in order to assess population trends. Three covariates, two 
related to sea ice habitat and yearly seal productivity, were used to 
assess the recapture probability for estimates of long-term trends in 
the size of the Northern Beaufort Sea population (Stirling et al. 2007, 
pp. 4-8). Associations between survival estimates and the three 
covariates (sea ice habitat variables and seal abundance) were not, in 
general, supported by the data. Population estimates (model averaged) 
from 2004-2006 (980) were not significantly different from estimates 
for the periods of 1972-1975 (745) and 1985-1987 (867). The abundance 
during the three sampling periods, 1972-1975, 1985-1987, and 2004-2006 
may be slightly low because (1) some bears residing in the extreme 
northern portions of the population may not have been equally available 
for capture and (2) the number of polar bears around Prince Patrick 
Island was not large relative to the rest of the population. Stirling 
et al. (2007, p. 10) concluded that currently the Northern Beaufort Sea 
population appears to be stable, probably because ice conditions remain 
suitable for feeding through much of the summer and fall in most years 
and harvest has not exceeded sustainable levels.

[[Page 28270]]

Other Populations

    As noted earlier in the ``Distribution and Movement'' and the 
``Polar Bear Seasonal Distribution Patterns Within Annual Activity 
Areas'' sections of this final rule, Stirling and Parkinson (2006, pp. 
261-275) investigated ice break-up relative to distribution changes in 
five other polar bear populations in Canada: Foxe Basin, Baffin Bay, 
Davis Strait, Western Hudson Bay, and Eastern Hudson Bay. They found 
that sea-ice break-up in Foxe Basin has been occurring about 6 days 
earlier each decade; ice break-up in Baffin Bay has been occurring 6 to 
7 days earlier per decade; and ice break-up in Western Hudson Bay has 
been occurring 7 to 8 days earlier per decade. Although long-term 
results from Davis Strait were not conclusive, particularly because the 
maximum percentage of ice cover in Davis Strait varies considerably 
more between years than in western Hudson Bay, Foxe Basin, or Baffin 
Bay, Stirling and Parkinson (2006, p. 269) did document a negative 
shortterm trend from 1991 to 2004 in Davis Strait. In eastern Hudson 
Bay, there was not a statistically significant trend toward earlier 
sea-ice break-up.
    In four populations, Western Hudson Bay, Foxe Basin, Baffin Bay, 
and Davis Strait, residents of coastal settlements have reported seeing 
more polar bears and having more problem bear encounters during the 
open-water season, particularly in the fall. In those areas, the 
increased numbers of sightings, as well as an increase in the number of 
problem bears handled at Churchill, Manitoba, have been interpreted as 
indicative of an increase in population size. As discussed earlier, the 
declines in population size, condition, and survival of young bears in 
the Western Hudson Bay population as a consequence of earlier sea ice 
break-up brought about by climate warming have all been well documented 
(Stirling et al. 1999, p. 294; Gagnon and Gough 2005; Regehr et al. 
2007a, p. 2,680). In Baffin Bay, the available data suggest that the 
population is being overharvested, so the reason for seeing more polar 
bears is unlikely to be an increase in population size. Ongoing 
research in Davis Strait (Peacock et al. 2007, pp. 6-7) indicates that 
this population may be larger than previously believed, which may at 
first seem inconsistent with the Stirling and Parkinson (2006, pp. 269-
270) hypothesis of declining populations over time. This observation, 
however, is not equilavent to an indication of population growth. The 
quality of previous population estimates for this region, and the lack 
of complete coverage of sampling used to derive the previous estimates, 
preclude establishment of a trend in numbers. Although the timing and 
location of availability of sea ice in Davis Strait may have been 
declining (Amstrup et al. 2007, p. 25), changes in numbers and 
distribution of harp seals at this time may support large numbers of 
polar bears even if ringed seals are less available (Stirling and 
Parkinson 2006, p. 270; Iverson et al. 2006, p. 110). As stated 
previously, continuing loss of sea ice ultimately will have negative 
effects on this population and other populations in the Seasonal Ice 
ecoregion.

Polar Bear Populations without Long-term Data Sets

    The remaining circumpolar polar bear populations either do not have 
data sets of sufficiently long time series or do not have data sets of 
comparable information that would allow the analysis of population 
trends or relationships to various environmental factors and other 
variables over time.

Projected Effects of Sea Ice Changes on Polar Bears

    This section reviews a study by Durner et al. (2007) that evaluated 
polar bear habitat features and future habitat distribution and 
seasonal availability into the future. Studies by Amstrup et al. (2007) 
and Hunter et al. (2007) are also reviewed which included new analyses 
and approaches to examine trends and relationships for populations or 
groups of populations based on commonly understood relationships with 
habitat features and environmental conditions.
    Habitat loss has been implicated as the greatest threat to the 
survival for most species (Wilcove et al. 1998, p. 614). Extinction 
theory suggests that the most vulnerable species are those that are 
specialized (Davis et al. 2004), long-lived with long generation times 
and low reproductive output (Bodmer et al. 1997), and carnivorous with 
large geographic extents and low population densities (Viranta 2003, p. 
1,275). Because of their specialized habitats and life history 
constraints (Amstrup 2003, p. 605), polar bears have many qualities 
that make their populations susceptible to the potential negative 
impacts of sea ice loss resulting from climate change.
    As discussed in detail in the ``Sea Ice Habitat'' section of this 
final rule, contemporary observations and state-of-the-art models point 
to a warming global climate, with some of the most accelerated changes 
in Arctic regions. In the past 30 years, average world surface 
temperatures have increased 0.2 degrees C per decade, but parts of the 
Arctic have experienced warming at a rate of 10 times the world average 
(Hansen et al. 2006). Since the late 1970s there have been major 
reductions in summer (multi-year) sea ice extent (Meier et al. 2007, 
pp. 428-434) (see detailed discussion in section entitled ``Summer Sea 
Ice''); decreases in ice age (Rigor and Wallace 2004; Belchansky et al. 
2005) and thickness (Rothrock et al. 1999; Tucker et al. 2001) (see 
detailed discussion in section entitled ``Sea Ice Thickness''); and 
increases in length of the summer melt period (Belchansky et al. 2004; 
Stroeve et al. 2005) (see detailed discussion in section entitled 
``Length of the Melt Period''). Recent observations further indicate 
that winter ice extent is declining (Comiso 2006) (see detailed 
discussion in section entitled ``Winter Sea Ice''). Empirical evidence 
therefore establishes that the environment on which polar bears depend 
for their survival has already changed substantially.
    Without sea ice, polar bears lack the platform that allows them to 
access prey. Longer melt seasons and reduced summer ice extent will 
force polar bears into habitats where their hunting success will be 
compromised (Derocher et al. 2004, p. 167; Stirling and Parkinson 2006, 
pp. 271-272). Increases in the duration of the summer season, when 
polar bears are restricted to land or forced over relatively 
unproductive Arctic waters, may reduce individual survival and 
ultimately population size (Derocher et al. 2004, pp. 165-170). Ice 
seals typically occur in open-water during summer and therefore are 
inaccessible to polar bears during this time (Harwood and Stirling 
1992, p. 897). Thus, increases in the length of the summer melt season 
have the potential to reduce annual availability of prey. In addition, 
unusual movements, such as long distance swims to reach pack ice or 
land, place polar bears at risk and may affect mortality (Monnett and 
Gleason 2006, pp. 4-6). Because of the importance of sea ice to polar 
bears, projecting patterns of ice habitat availability has direct 
implications on their future status. This section reports on recent 
studies that project the effects of sea ice change on polar bears.

Polar Bear Habitat

    Durner et al. (2007, pp. 4-10) developed resource selection 
functions (RSFs) to identify ice habitat characteristics selected by 
polar bears and used these selection criteria as a basis for projecting 
the future availability of optimal polar bear habitat throughout the 
21st century. Location

[[Page 28271]]

data from satellite-collared polar bears and environmental data (e.g., 
sea ice concentration, bathymetry, etc.) were used to develop RSFs 
(Manly et al. 2002), which are considered to be a quantitative measure 
of habitat selection by polar bears. Important habitat features 
identified in the RSF models were then used to determine the 
availability of optimal polar bear habitat in GCM projections of 21st 
century sea ice distribution. The following information has been 
excerpted or extracted from Durner et al. (2007).
    Durner et al. (2007, p. 5) used the outputs from 10 GCMs from the 
IPCC 4AR report as inputs into RSFs models to forecast future 
distribution and quantities of preferred polar bear habitat. The 10 
GCMs were selected based on their ability to accurately simulate actual 
ice extent derived from passive microwave satellite observations (as 
described in DeWeaver 2007). The area of the assessment was the pelagic 
ecoregion of the Arctic polar basin comprised of the Divergent and 
Convergent ecoregions described by Amstrup et al. (2007, pp. 5-7) as 
described previously in introductory materials contained in the ``Polar 
Bear Ecoregions'' section of this final rule. Predictions of the amount 
and rate of change in polar bear habitat varied among GCMs, but all 
predicted net losses in the polar basin during the 21st century. 
Projected losses in optimal habitat were greatest in the peripheral 
seas of the polar basin (Divergent ecoregion) and projected to be 
greatest in the Southern Beaufort, Chukchi, and Barents Seas. Observed 
losses of sea ice in the Southern Beaufort, Chukchi, and Barents Seas 
are occurring more rapidly than projected and suggest that trajectories 
may vary at regional scales. Losses were least in high-latitude regions 
where the RSF models predicted an initial increase in optimal habitat 
followed by a modest decline. Optimal habitat changes in the Queen 
Elizabeth and Arctic Basin units of the Canada-Greenland group 
(Convergent ecoregion) were projected to be negligible if not 
increasing. Very little optimal habitat was observed or predicted to 
occur in the deep water regions of the central Arctic basin.
    Durner et al. (2007, p. 13) found that the largest seasonal 
reductions in habitat were predicted for spring and summer. Based on 
the multi-model mean of 10 GCMs, the average area of optimal polar bear 
habitat during summer in the polar basin declined from an observed 1.0 
million sq km (0.39 million sq mi) in 1985-1995 (baseline) to a 
projected multi-model average of 0.58 million sq km (0.23 million sq 
mi) in 2045-2054 (42 percent decline), 0.36 million sq km (0.14 million 
sq mi) in 2070-2079 (64 percent decline), and 0.32 million sq km (0.12 
million sq mi) in 2090-2099 (68 percent decline). After summer melt, 
most regions of the polar basin were projected to refreeze throughout 
the 21st century. Therefore, winter losses of polar bear habitat were 
more modest, from 1.7 million sq km (0.54 million sq mi) in 1985-1995 
to 1.4 million sq km (0.55 million sq mi) in 2090-2099 (17 percent 
decline). Simulated and projected rates of habitat loss during the late 
20th and early 21st centuries by many GCMs tend to be less than 
observed rates of loss during the past two decades; therefore, habitat 
losses based on GCM multi-model averages were considered to be 
conservative.
    Large declines in optimal habitat are projected to occur in the 
Alaska-Eurasia region (Divergent ecoregion) where 60-80 percent of the 
polar bear's historical area of spring and summer habitat may disappear 
by the end of the century (Durner et al. 2007). The Canada-Greenland 
region (Convergent ecoregion) has historically contained less total 
optimal habitat area, since it is geographically smaller than the 
Alaska-Eurasia region. In the Queen Elizabeth region, while there is a 
similar seasonal pattern to the projected loss of optimal habitat, the 
magnitude of habitat loss was much less because of the predicted 
stability of ice in this region (Durner et al. 2007, p. 13). The 
projected rates of habitat loss over the 21st century were not constant 
over time (Durner et al. 2007). Rates of loss tended to be greatest 
during the second and third quarters of the century and then diminish 
during the last quarter.
    Losses in optimal habitat between 1985-1995 and 1996-2006 
established an observed trajectory of change that was consistent with 
the GCM projections; however, the observed rate of change (established 
over a 10-year period), when extrapolated over the first half of the 
21st century, resulted in more habitat lost than that projected by the 
GCM ensemble average (i.e., faster than projected) (Durner et al. 2007, 
p. 13).
    The recent findings regarding the record minimum summer sea ice 
conditions for 2007 reported by the NSIDC in Boulder, Colorado, were 
not considered in the analysis of sea ice conditions reported by Durner 
et al. (2007) because the full 2007 data were not yet available when 
the analyses in Durner et al. (2007) were conducted. In 2007, sea ice 
losses in the Canadian Archipelago and the polar basin Convergent 
ecoregions were the largest observed to date; these areas had 
previously been observed to be relatively stable (Durner et al. 2007).
    Durner et al. (2007, pp. 18-19) indicated that less available 
habitat will likely result in reduced polar bear populations, although 
the precise relationship between habitat loss and population 
demographics remains unknown. Other authors (Stirling and Parkinson 
2006, pp. 271-272; Regehr et al. 2007, pp. 14-18; Hunter et al. 2007, 
pp. 14-18; Rode et al. 2007, pp. 5-8; Amstrup et al. 2007, pp. 19-31) 
present detailed information regarding demographic effects of loss of 
sea ice habitat. Durner et al. (2007, pp. 19-20) does hypothesize that 
density effects may become more important as polar bears make long 
distance annual migrations from traditional winter areas to remnant 
high-latitude summer areas already occupied by polar bears. Further, 
Durner et al. (2007, p. 19) indicate that declines and large seasonal 
swings in habitat availability and distribution may impose greater 
impacts on pregnant females seeking denning habitat or leaving dens 
with cubs than on males and other age groups. Durner et al. (2007, p. 
19) found that although most winter habitats would be replenished 
annually, long distance retreat of summer habitat may ultimately 
preclude bears from seasonally returning to their traditional winter 
ranges. Please also see the section in this final rule entitled 
``Access to and Alteration of Denning Areas.''

Polar Bear Population Projections--Southern Beaufort Sea

    Recent demographic analyses and modeling of the Southern Beaufort 
Sea population have provided insight about the current and future 
status of this population (Hunter et al. 2007; Regehr et al. 2007b). 
This population occupies habitats similar to four other populations in 
the Divergent ecoregion (Barents, Chukchi, Kara and Laptev Seas), which 
together represent over one-third of the current worldwide polar bear 
population. Because these other populations have experienced more 
severe sea ice changes than the southern Beaufort Sea, this assessment 
may understate the severity of the demographic impact that polar bear 
populations face in the Divergent ecoregion.
    Hunter et al. (2007, pp. 2-6) conducted a demographic analysis of 
the Southern Beaufort Sea population using a life-cycle model 
parameterized with vital rates estimated from capture-recapture data 
collected between 2001 and 2006 (Regehr et al. 2007b, pp. 12-

[[Page 28272]]

14). Population growth rates and resultant population sizes were 
projected both deterministically (i.e., assuming that environmental 
conditions remained constant over time) and stochastically (i.e., 
allowing for environmental conditions to vary over time).
    The deterministic model produced positive point estimates of 
population growth rate under the conditions in 2001-2003, ranging from 
1.02 to 1.08 (i.e., 2 to 8 percent growth per year), and negative point 
estimates of population growth rate under the conditions in 2004-2005 
when the region was ice-free for much longer, ranging from 0.77 to 0.90 
(i.e., 23 to 10 percent decline per year) (Hunter et al. 2007, p. 8). 
The overall growth rate estimate for the study period was about 0.997, 
i.e., a 0.3 percent decline per year. Population growth rate was most 
affected by adult female survival, with secondary effects from reduced 
breeding probability (Hunter et al. 2007, p. 8). A main finding of this 
analysis was that when there are more than 125 ice-free days over the 
continental shelf of the broad southern Beaufort Sea region, population 
growth rate declines precipitously.
    The stochastic model incorporated environmental variability by 
partitioning observed data into ``good'' years (2001-2003, short ice-
free period) and ``bad'' years (2004-2005, long ice-free period), and 
evaluating the effect of the frequency of bad years on population 
growth rate (Hunter et al. 2007, p. 6). Stochastic projections were 
made in two ways: (1) Assuming a variable environment with the 
probability of bad years equal to what has been observed recently 
(1979-2006); and (2) assuming a variable environment described by 
projections of sea ice conditions in outputs of 10 selected general 
circulation models, as described by DeWeaver (2007). In the first 
analysis, Hunter et al. (2007, pp. 12-13) found that the stochastic 
growth rate declined with an increase in frequency of bad years, and 
that if the frequency of bad years exceeded 17 percent the result would 
be population decline. The observed frequency of bad years since 1979 
indicated a decline of about 1 percent per year for the Southern 
Beaufort Sea population. The average frequency of bad ice years from 
1979-2006 was approximately 21 percent and from 2001-2005 was 
approximately 40 percent. In the second analysis, using outputs from 10 
GCMs to determine the frequency of bad years, Hunter et al. (2007, p. 
13) estimated a 55 percent probability of decline to 1 percent of 
current population size in 45 years using the non-covariate model set, 
and a 40 percent probability of decline to 0.1 percent of current 
population size in 45 years, also using the non-covariate model set. 
Under sea ice conditions predicted by each of the 10 GCMs, the Southern 
Beaufort Sea population was projected to experience a significant 
decline within the next century. The demographic analyses of Hunter et 
al. (2007, pp. 3-9) incorporated uncertainty arising from demographic 
parameter estimation, the short time-series of capture-recapture data, 
the form of the population model, environmental variation, and climate 
projections. Support for the conclusions come from the agreement of 
results from different statistical model sets, deterministic and 
stochastic models, and models with and without climate forcing.

Polar Bear Population Projections--Range-wide

    Amstrup et al. (2007, pp. 5-6) used two modeling approaches to 
estimate the future status of polar bears in the 4 ecoregions they 
delineated (see section entitled ``Polar Bear Ecoregions'' and Figure 2 
above). First, they used a deterministic Carrying Capacity Model (CM) 
that applied current polar bear densities to future GCM sea ice 
projections to estimate potential future numbers of polar bears in each 
of the 4 ecoregions. The second approach, a Bayesian Network Model 
(BM), included the same annual measure of sea ice area as well as 
measures of the spatial and temporal availability of sea ice. In 
addition, the BM incorporated numerous other stressors that might 
affect polar bear populations that were not incorporated in the 
carrying capacity model. The CM ``provided estimates of the maximum 
potential sizes of polar bear populations based on climate modeling 
projections of the quantity of their habitat--but in the absence of 
effects of any additional stressors * * *'' while the BM ``provided 
estimates of how the presence of multiple stressors * * * may affect 
polar bears'' (Amstrup et al. 2007, p. 5).
    For both modeling approaches, the 19 polar bear populations were 
grouped into 4 ecoregions, which are defined by the authors on the 
basis of observed temporal and spatial patterns of ice formation and 
ablation (melting or evaporation), observations of how polar bears 
respond to these patterns, and projected future sea ice patterns (see 
``Current Population Status and Trends'' section). The four ecoregions 
are: (1) the Seasonal Ice ecoregion (which occurs mainly at the 
southern extreme of the polar bear range); (2) the Archipelago 
ecoregion of the central Canadian Arctic; (3) the polar basin Divergent 
ecoregion; and (4) the polar Basin Convergent ecoregion (see Figure 2 
above). The ecoregions group polar bear populations that share similar 
environmental conditions and are, therefore, likely to respond in a 
similar fashion to projected future conditions.

Carrying Capacity Model (CM)

    The deterministic Carrying Capacity Model (CM) developed by Amstrup 
et al. (2007) was used to estimate present-day polar bear density in 
each ecoregion based on estimates of the number of polar bears and 
amount of sea ice in each ecoregion. These density estimates were 
defined as ``carrying capacities'' and applied to projected future sea 
ice availability scenarios using the assumption that current ``carrying 
capacities'' will apply to available habitat in the future. This 
density and habitat index, therefore, allows a straightforward 
comparison between the numbers of bears that are present now and the 
number of bears which might be present in the future.
    Amstrup et al. (2007, p. 8) defined total available sea ice habitat 
in the Divergent and Convergent ecoregions as the 12-month sum of sea 
ice cover (in km2) over the continental shelves of the 2 polar basin 
ecoregions; in the Archipelago and Seasonal Ice ecoregions, all sea 
ice-covered areas were considered shelf areas and defined as available 
habitat (Amstrup et al. 2007, p. 9). In the Divergent and Convergent 
ecoregions, available sea ice habitat was further defined as either 
optimal (according to the definition of Durner et al. 2007, p. 9) or 
nonoptimal; this further subdivision was not applied in the Archipelago 
and Seasonal Ice ecoregions, which used the one measure of total 
available sea ice habitat. Projections of future sea ice availability 
for each ecoregion were derived from 10 General Circulation Models 
(GCMs) selected by DeWeaver (2007, p. 21). Projections of polar bear 
status based on habitat availability were determined for each of the 
four ecoregions for 4 time periods: the present (year 0); 45 years from 
the present (the decade of 2045-2055); 75 years from the present (2070-
2080); and 100 years (2090-2100) from the present. For added 
perspective, the authors also looked at 10 years in the past (1985-
1995). Three sea ice habitat availability estimates were derived for 
each time period, based on the minimum, mean, and maximum sea ice 
projections from the 10-model GCM ensemble. Changes in habitat were 
defined in terms of direction (contracting, stable or expanding) and

[[Page 28273]]

magnitude (slow or none, moderate, or fast), while changes in carrying 
capacity were defined in terms of direction (decreasing, stable or 
increasing) and magnitude (low to none, moderate, or high) (Amstrup et 
al. 2007, pp. 10-12). ``Outcomes of habitat change and carrying 
capacity change were categorized into 4 composite summary categories to 
describe the status of polar bear populations: enhanced, maintained, 
decreased, or toward extirpation'' (Amstrup et al. 2007, p. 12).
    The range of projected carrying capacities (numbers of bears 
potentially remaining assuming historic densities were maintained) 
varied by ecoregion and to whether maximum or minimum ice values were 
used. Table 1 below presents the range of projected change in carrying 
capacity of sea ice habitats for polar bears by ecoregion based on sea 
ice projections from GCMs. The range of percentages represents minimum 
and maximum projected changes in carrying capacity based on minimum and 
maximum projected changes in the total area of sea ice habitat at 
various times.
[GRAPHIC] [TIFF OMITTED] TR15MY08.011

    All CM runs projected declines in polar bear carrying capacity in 
all four ecoregions (Amstrup et al. 2007, Figure 9). Some CM model runs 
project that polar bear carrying capacity will be trending ``toward 
extirpation'' (the term ``toward extirpation'' is defined as one of 
three combinations of habitat change and carrying capacity change 
(i.e., contracting moderate habitat change, decreasing fast carrying 
capacity change; contracting fast, decreasing moderate; contracting 
fast, decreasing high)) in some ecoregions at certain times, but that 
less severe carrying capacity changes will occur in other ecoregions 
(see Tables 2 and 6, and Figure 9 in Amstrup et al. 2007). Using the 4 
composite summary categories of Amstrup et al. (2007, p. 12), the 
minimum sea ice extent model results project that a trend toward 
extirpation of polar bears will appear in the polar basin Divergent 
ecoregion by year 45 and in the Seasonal Ice ecoregion by year 75. Mean 
sea ice extent model results project that a trend toward extirpation of 
bears will appear in the polar basin Divergent ecoregion by year 75 and 
in the polar basin Convergent ecoregion by year 100. None of the model 
results project that a trend toward extirpation will appear in the 
Archipelago region by year 100. Likewise, none of the model results 
project that polar bear carrying capacity will increase or remain 
stable in any ecoregion beyond 45 years. Although the pattern of 
projected carrying capacity varied greatly among regions, the summary 
finding was for a range-wide decline in polar bear carrying capacity of 
between 10 and 22 percent by year 45 and between 22 and 32 percent by 
year 75 (Amstrup et al. 2007, p. 20). CM results provide a conservative 
view of the potential magnitude of change in bear carrying capacity 
over time and area, because these results are based solely on the area 
of sea ice present at a given point in time and do not consider the 
effects of other population stressors.

Bayesian Network Model (BM)

    To address other variables in addition to sea ice habitat that may 
affect polar bears, Amstrup et al. (2007, pp. 5-6) developed a 
prototype Bayesian Network Model (BM). The BM incorporated empirical 
data and GCM projections of annual and seasonal sea ice availability, 
numerous other stressors, and expert judgment regarding known 
relationships between these stressors and polar bear demographics to 
obtain probabilistic estimates of future polar bear distributions and 
relative numbers. Anthropogenic stressors included human activities 
that could affect distribution or abundance of polar bears, such as 
hunting, oil and gas development, shipping, and direct bear-human 
interactions. Natural stressors included changes in the availability of 
primary and alternate prey and foraging areas, and occurrence of 
parasites, disease, and predation. Environmental factors included 
projected changes in total ice and optimal habitat, changes in the 
distance that ice retreats from traditional autumn or winter foraging 
areas, and changes in the number of months per year that ice is absent 
in the continental shelf regions. Habitat changes, natural and 
anthropogenic stressors, and environmental factors were evaluated for 
their potential effects on the density and distribution of polar bears 
and survival throughout their range. BM outcomes were defined according 
to their collective influence on polar bear

[[Page 28274]]

population distribution and relative numbers with respect to current 
conditions (e.g., larger than now, the same as now, smaller than now, 
rare, or extinct) (Amstrup et al. 2007).
    As a caveat to their results, the authors note that, because a BM 
combines expert judgment and interpretation with quantitative and 
qualitative empirical information, inputs from multiple experts are 
usually incorporated into the structure and parameterization of a 
``final'' BM. Because the BM in Amstrup et al. (2007) incorporates the 
input of a single polar bear expert, the model should be viewed as an 
``alpha'' level prototype (Marcot et al. 2006, cited in Amstrup et al. 
2007, p.27) that would benefit from additional development and 
refinement. Given this caveat, it is extremely important, while 
interpreting model outcomes, to focus on the general direction and 
magnitude of the probabilities of projected outcomes rather than the 
actual numerical probabilities associated with each outcome. For 
example, situations with high probability of a particular outcome 
(e.g., of extinction) or consistent directional effect across sea ice 
scenarios suggest a higher likelihood of that outcome as opposed to 
situations where the probability is evenly spread across outcomes or 
where there is large disagreement among different sea ice scenarios. 
These considerations were central to the authors' interpretation of BM 
results (Amstrup et al. 2007).
    The overall outcomes from the BM indicate that in each of the four 
ecoregions polar bear populations in the future are very likely to be 
smaller and have a higher likelihood of experiencing multiple stressors 
in comparison to the past or present. In the future, multiple natural 
and anthropogenic stressors will likely become important, and negative 
effects on all polar bear populations will be apparent by year 45 with 
generally increased effects through year 100.
    In the Seasonal Ice ecoregion the dominant outcome of the BM was 
``extinct'' at all future time periods under all three GCM scenarios 
used in the analysis, with low probabilities associated with 
alternative outcomes, except for the minimum GCM scenario at year 45 
(when the probability of alternative outcomes was around 44 percent). 
The small probabilities for outcomes other than extinct suggest a trend 
in this ecoregion toward probable extirpation by the mid-21st century. 
In the polar basin Divergent ecoregion, ``extinct'' was also the 
predominant outcome, with very low probabilities associated with 
alternative outcomes (i.e., less then 15 percent probability of not 
becoming extinct). The small probabilities for outcomes other than 
extinct also suggest a trend in this ecoregion toward probable 
extirpation by the mid-21st century. In the polar basin Convergent 
ecoregion, population persistence at ``smaller in numbers'' or ``rare'' 
was the predominant outcome at year 45, but the probability of 
extinction came to predominate (i.e., was greater than 60 percent) at 
year 75 and year 100. In the Archipelago ecoregion, a smaller 
population was the most probable outcome at year 45 under all GCM 
scenarios. By year 75, the most probable outcome for this ecoregion (as 
in the other ecoregions) across all GCM ice scenarios was population 
persistence, albeit in lower numbers. Even late in the century, 
however, the probability of a smaller than present population in the 
Archipelago Ecoregion was relatively high. Therefore, Amstrup et al. 
(2007) concluded that polar bears, in reduced numbers, could occur in 
the Archipelago Ecoregion through the end of the century. The authors 
note that the projected changes in sea ice conditions could result in 
loss of approximately two-thirds of the world's current polar bear 
population by the mid-21st century. They further note that, because the 
observed trajectory of Arctic sea ice decline appears to be 
underestimated by currently available models, these projections may be 
conservative.
    As part of the BM, Amstrup et al. (2007, pp. 29-31) conducted a 
sensitivity analysis to determine the influence of model inputs and 
found that the overall projected population outcome was greatly 
influenced by changes in sea ice habitat. The Bayesian sensitivity 
analysis found that 91 percent of the variation in the overall 
predicted population outcome was determined by six variables. Four of 
these six were sea ice related, including patterns of seasonal and 
spatial distribution. The fifth variable among these top six was the 
ecoregion being considered. Outcomes varied for ecoregions as a result 
of differences in their sea ice characteristics. The sixth ranked 
variable, with regard to overall population outcome, was the level of 
intentional takes or harvest (overutilization). The stressors that 
related to bear-human interactions, parasites and disease and 
predation, and other natural or man-made factors provided a nominal 
influence of less than 9 percent contribution to the status outcome.
    Amstrup et al. (2007, pp. 22-24) characterize the types and 
implications of uncertainty inherent to the carrying capacity and BM 
modeling in their report. Analyses in this report contain three main 
categories of uncertainty: (1) uncertainty in our understandings of the 
biological, ecological, and climatological systems; (2) uncertainty in 
the representation of those understandings in models and statistical 
descriptions; and (3) uncertainty in model predictions. In addition, 
Amstrup et al. (2007) discussed potential consequences of and efforts 
to evaluate and minimize uncertainty in the analyses. We reiterate the 
caveat that a BM combines expert judgment and interpretation with 
quantitative and qualitative empirical information, therefore 
necessitating inputs from multiple experts (if available) before it can 
be considered final. We note again that because the BM presented in 
Amstrup et al. (2007) incorporates the input of a single polar bear 
expert, it should be viewed as a first-generation prototype (Marcot et 
al. 2006, cited in Amstrup et al. 2007, p.27) that would benefit from 
additional development.
    Because the BM includes numerous qualitative inputs (including 
expert assessment) and requires additional development (Amstrup et al. 
2007, p. 27), we are more confident in the general direction and 
magnitude of the projected outcomes rather than the actual numerical 
probabilities associated with each outcome, and we are also more 
confident in outcomes within the 45-year foreseeable future than in 
outcomes over longer timeframes (e.g., year 75 and year 100 in Amstrup 
et al. (2007)). We conclude that the outcomes of the BM are consistent 
with ``the increasing volume of data confirming negative relationships 
between polar bear welfare and sea ice decline'' (Amstrup et al. 2007, 
p. 31), and parallel other assessments of both the demographic 
parameter changes as well as trends in various factors that threaten 
polar bears as described by Derocher et al. (2004), and in the proposed 
rule to list polar bears as a threatened species (72 FR 1064). However, 
because of the preliminary nature of the BM and levels of uncertainty 
associated with the initial Bayesian Modeling efforts, we do not find 
that the projected outcomes derived from the BM to be as reliable as 
the data derived from the ensemble of climate models used by the 
Service to gauge the loss of sea ice habitat over the next 45 years. 
Both the proposed rule and the status assessment (Range Wide Status 
Review of the Polar Bear (Ursus maritimus), Schliebe et al. 2006a), 
underwent extensive peer review by impartial experts within the 
disciplines of polar bear ecology, climatology, toxicology, seal 
ecology, and traditional ecological knowledge, and thereby

[[Page 28275]]

represent a consensus on the conclusions in these documents. The more 
recent projections from the BM exercise conducted by Amstrup et al. 
(2007) are consistent with conclusions reached in the earlier 
assessments that polar bear populations will continue to decline in the 
future.

Polar Bear Mortality

    As changes in habitat become more severe and seasonal rates of 
change more rapid, catastrophic mortality events that have yet to be 
realized on a large scale are expected to occur. Observations of 
drownings and starved animals may be a prelude to such events. 
Populations experiencing compromised physical condition will be 
increasingly prone to sudden die-offs. While no information currently 
exists to evaluate such events, the possibility of other forms of 
unanticipated mortality are mentioned here because they have been 
observed in other species (e.g., canine distemper in Caspian seals 
(Phoca caspica) (Kuiken et al. 2006, p. 321) and phocine distemper 
virus in harbor seals (Heide-Jorgensen et al. 1992, cited in Goodman 
1998).

Conclusion Regarding Current and Projected Demographic Effects of 
Habitat Changes on Polar Bears

    Polar bears have evolved in a sea ice environment that serves as an 
essential platform from which they meet life functions. Polar bears 
currently are exposed to a rapidly changing sea ice platform, and in 
many regions of the Arctic already are being affected by these changes. 
Sea ice changes are projected to continue and positive feedbacks are 
expected to amplify changes in the arctic which will hasten sea ice 
retreat. These factors will likely negatively impact polar bears by 
increasing energetic demands of seeking prey. Remaining members of many 
populations will be redistributed, at least seasonally, into 
terrestrial or offshore habitats with marginal values for feeding, and 
increasing levels of negative bear-human interactions. Increasing 
nutritional stress will coincide with exposure to numerous other 
potential stressors. Polar bears in some regions already are 
demonstrating reduced physical condition, reduced reproductive success, 
and increased mortality. As changes in habitat become more severe and 
seasonal rates of change more rapid, catastrophic mortality events that 
have yet to be realized on a large scale are expected to occur. 
Observations of drownings and starved animals may be a prelude to such 
events. These changes will in time occur throughout the world-wide 
range of polar bears. Ultimately, these inter-related factors will 
result in range-wide population declines. Populations in different 
ecoregions will experience different rates of change and timing of 
impacts. Within the foreseeable future, however, all ecoregions will be 
affected.

Conclusion for Factor A

Rationale

    Polar bears evolved over thousands of years to life in a sea ice 
environment. They depend on the sea ice-dominated ecosystem to support 
essential life functions. Sea ice provides a platform for hunting and 
feeding, for seeking mates and breeding, for movement to terrestrial 
maternity denning areas and occasionally for maternity denning, for 
resting, and for long-distance movements. The sea ice ecosystem 
supports ringed seals, primary prey for polar bears, and other marine 
mammals that are also part of their prey base.
    Sea ice is rapidly diminishing throughout the Arctic. Patterns of 
increased temperatures, earlier onset of and longer melting periods, 
later onset of freeze-up, increased rain-on-snow events, and potential 
reductions in snowfall are occurring. In addition, positive feedback 
systems (i.e., the sea-ice albedo feedback mechanism) and naturally 
occurring events, such as warm water intrusion into the Arctic and 
changing atmospheric wind patterns, can operate to amplify the effects 
of these phenomena. As a result, there is fragmentation of sea ice, a 
dramatic increase in the extent of open water areas seasonally, 
reduction in the extent and area of sea ice in all seasons, retraction 
of sea ice away from productive continental shelf areas throughout the 
polar basin, reduction of the amount of heavier and more stable multi-
year ice, and declining thickness and quality of shore-fast ice. Such 
events are interrelated and combine to decrease the extent and quality 
of sea ice as polar bear habitat during all seasons and particularly 
during the spring-summer period. Arctic sea ice will continue to be 
affected by climate change. Due to the long persistence time of certain 
GHGs in the atmosphere, the current and projected patterns of GHG 
emissions over the next few decades, and interactions among climate 
processes, climate changes for the next 40-50 years are already largely 
set (IPCC 2007, p. 749; J. Overland, NOAA, in litt. to the Service, 
2007). Climate change effects on sea ice and polar bears will continue 
through this timeframe and very likely further into the future.
    Changes in sea ice negatively impact polar bears by increasing the 
energetic demands of movement in seeking prey, causing seasonal 
redistribution of substantial portions of populations into marginal ice 
or terrestrial habitats with limited values for feeding, and increasing 
the susceptibility of bears to other stressors, some of which follow. 
As the sea ice edge retracts to deeper, less productive polar basin 
waters, polar bears will face increased competition for limited food 
resources, increased open water swimming with increased risk of 
drowning, increasing interaction with humans with negative 
consequences, and declining numbers that may be unable to sustain 
ongoing harvests.
    Changes in sea ice will reduce productivity of most ice seal 
species, result in changes in composition of seal species indigenous to 
some areas, and eventually result in a decrease in seal abundance. 
These changes will decrease availability or timing of availability of 
seals as food for polar bears. Ringed seals will likely remain 
distributed in shallower, more productive southerly areas that are 
losing their seasonal sea ice and becoming characterized by vast 
expanses of open water in the spring-summer-fall period. As a result, 
the seals will remain unavailable as prey to polar bears during 
critical times of the year. These factors will, in turn, result in a 
steady decline in the physical condition of polar bears, which has 
proven to lead to population-level demographic declines in reproduction 
and survival.
    The ultimate net effect of these inter-related factors will be that 
polar bear populations will decline or continue to decline. Not all 
populations will be affected evenly in the level, rate, and timing of 
effects, but we have determined that, within the foreseeable future, 
all polar bear populations will be negatively affected. This 
determination is broadly supported by results of the USGS studies, and 
within the professional community, including a majority of polar bear 
experts who peer reviewed the proposed rule. The PBSG evaluated 
potential impacts to the polar bear, and determined that the observed 
and projected changes in sea ice habitat would negatively affect the 
species (Aars et al. 2006, p. 47). The IUCN, based on the PBSG 
assessment, reclassified polar bears as ``vulnerable.'' Similarly, 
their justification for the classification was the projected change in 
sea ice, effect of climate change on polar bear condition, and 
corresponding effect on reproduction and survival, which have been 
associated with a steady and persistent decline in abundance.
    A series of analyses of the best available scientific information 
on the

[[Page 28276]]

ecology and demography of polar bears were recently undertaken by the 
USGS at the request of the Secretary of the Interior. These include 
additional analyses of some specific populations (Southern Beaufort 
Sea, Northern Beaufort Sea, Southern Husdon Bay), analysis of optimal 
polar bear habitat and projections of optimal habitat through the 21st 
century, projections of the status of populations into the future, and 
information from a pilot study regarding the increase in travel 
distance for pregnant females to reach denning areas on the North Slope 
of Alaska with insights to potential consequences. Results of the 
analyses are detailed within this final rule. This significant effort 
enhanced and reaffirmed our understanding of the interrelationships of 
ecological factors and the future status of polar bear populations.
    The USGS report by Amstrup et al. (2007) synthesized historical and 
recent scientific information and conducted two modeling exercises to 
provide a range-wide assessment of the current and projected future 
status of polar bears occupying four ecoregions. In this effort, using 
two approaches and validation processes, the authors described four 
``ecoregions'' based on current and projected sea ice conditions and 
developed a suite of population projections by ecoregion. This 
assessment helps inform us on the future fate of polar bear populations 
subject to a rapidly changing sea ice environment. In summary, polar 
bear populations within all ecoregions were not uniformly impacted, but 
all populations within ecoregions declined, with the severity of 
declines depending on the sea ice projections (minimal, mean, maximum), 
season of the year, and area. Amstrup et al. (2007, p. 36) forecasts 
the extirpation of populations in the Seasonal Ice, and polar basin 
Divergent ecoregions by the mid-21st century. Because the BM presented 
in the report be viewed as a first-generation prototype (Marcot et al. 
2006, cited in Amstrup et al. 2007, p.27) that would benefit from 
additional development, and because the BM includes numerous 
qualitative inputs (including expert assessment), we are more confident 
in the general direction and magnitude of the projected outcomes rather 
than the actual numerical probabilities associated with each outcome, 
and we are also more confident in outcomes within the 45-year 
foreseeable future.
    In the southerly populations (Seasonal Ice ecoregion) of Western 
Hudson Bay, Southern Hudson Bay, Foxe Basin, Davis Strait, and Baffin 
Bay, polar bears already experience stress from seasonal fasting due to 
early sea ice retreat, and have or will be affected earliest (Stirling 
and Parkinson 2006, p. 272; Obbard et al. 2006, pp. 6-7; Obbard et al. 
2007, p. 14). Populations in the Divergent ecoregion, including the 
Chukchi Sea, Barents Sea, Southern Beaufort Sea, Kara Sea, and Laptev 
Sea will, or are currently, experiencing initial effects of changes in 
sea ice (Rode et al. 2007, p. 12; Regehr et al. 2007b, pp. 18-19; 
Hunter et al. 2007, p. 19; Amstrup et al. 2007, p. 36). These 
populations are vulnerable to large-scale dramatic seasonal 
fluctuations in ice movements, decreased abundance and access to prey, 
and increased energetic costs of hunting. Polar bear populations 
inhabiting the central island archipelago of Canada (Archipelago 
ecoregion) will also be affected but to lesser degrees and later in 
time. These more northerly populations (Norwegian Bay, Lancaster Sound, 
M'Clintock Channel, Viscount Melville Sound, Kane Basin, and the Gulf 
of Boothia) are expected to be affected last due to the buffering 
effects of the island archipelago complex, which lessens effects of 
oceanic currents and seasonal retractions of ice and retains a higher 
proportion of heavy, more stable, multi-year sea ice. A caution in this 
evaluation is that historical record minimum summer ice conditions in 
September 2007 resulted in vast ice-free areas that encroached into the 
area of permanent polar sea ice in the central Arctic Basin, and the 
Northwest Passage was open for the first time in recorded history. The 
record low sea ice conditions of 2007 are an extension of an 
accelerating trend of minimum sea ice conditions and further support 
the concern that current sea ice models may be conservative and 
underestimate the rate and level of change expected in the future.
    Although climate change may improve conditions for polar bears in 
some high latitude areas where harsh conditions currently prevail, 
these improvements will only be transitory. Continued warming will lead 
to reduced numbers and reduced distribution of polar bears range-wide 
(Regehr et al. 2007b, p. 18; Derocher et al. 2004, p. 19; Hunter et al. 
2007, p. 14; Amstrup et al. 2007, p. 36). Projected declines in the sea 
ice for most parts of the Arctic are long-term, severe, and occurring 
at a pace that is unprecedented (Comiso 2003; ACIA 2004; Holland et al. 
2006, pp. 1-5); therefore, the most northerly polar bear populations 
will experience declines in demographic parameters similar to those 
observed in the Western Hudson Bay population, along with changes in 
distribution and other currently unknown ecological responses (Derocher 
et al. 2004, p. 171; Aars et al. 2006, p. 47). Ultimately, all polar 
bear populations will be affected within the foreseeable future, and 
the species will likely become in danger of extinction throughout all 
of its range.
    It is possible, even with the total loss of summer sea ice, that a 
small number of polar bears could survive, provided there is adequate 
seasonal ice cover to serve as a platform for hunting opportunities, 
and that sea ice is present for a period of time adequate for 
replenishment of body fat stores and condition. However, this 
possibility is difficult to evaluate. As a species, polar bears have 
survived at least two warming periods, the Last Interglacial (140,000--
115,000 years Before Present (BP)), and the Holocene Thermal maximum 
(ca 12,000--4,000 BP) (Dansgaard et al. 1993, p. 218; Dahl-Jensen et 
al. 1998, p. 268). Greenland ice cores revealed that the climate was 
much more variable in the past, and some of the historical shifts 
between the warm and cold periods were rapid, suggesting that the 
recent relative climate stability seen during the Holocene may be an 
exception (Dansgaard et al. 1993, p. 218). While the precise impacts of 
these warming periods on polar bears and the Arctic sea ice habitat are 
unknown, the ability of polar bears to adapt to alternative food 
sources seems extremely limited given the caloric requirements of adult 
polar bears and the documented effects of nutritional stress on 
reproductive success.
    In addition to the effects of climate change on sea ice, we have 
also evaluated changes to habitat in the Arctic as a result of 
increased pressure from human activities. Increased human activities 
include a larger footprint from the number of people resident to the 
area, increased levels of oil and gas exploration and development and 
expanding areas of interest, and potential increases in shipping. 
Cumulatively, these activities may result in alteration of polar bear 
habitat. Any potential impact from these activities would be additive 
to other factors already or potentially affecting polar bears and their 
habitat. We acknowledge that the sum total of documented direct impacts 
from these activities in the past have been minimal. We also 
acknowledge, as discussed further under the Factor D analysis in this 
final rule, that national and local concerns for these activities has 
resulted in the development and implementation of multi-layered 
regulatory programs to monitor and eliminate or minimize potential 
effects. Regarding potential

[[Page 28277]]

shipping activities within the Arctic, increased future monitoring is 
necessary to enhance the understanding of potential effects from this 
activity.

Determination for Factor A

    We have evaluated the best available scientific and commercial 
information on polar bear habitat and the current and projected effects 
of various factors (including climate change) on the quantity and 
distribution of polar bear habitat, and have determined that the polar 
bear is threatened throughout its entire range by ongoing and projected 
changes in sea ice habitat (i.e., the species is likely to become 
endangered throughout all of its range within the foreseeable future 
due to habitat loss).

Factor B. Overutilization for Commercial, Recreational, Scientific, or 
Educational Purposes

    Use of polar bears for commercial, recreational, scientific, and 
educational purposes is generally low, with the exception of harvest. 
Use for nonlethal scientific purposes is highly regulated and does not 
pose a threat to populations. Similarly, the regulated, low-level use 
for educational purposes through placement of cubs or orphaned animals 
into zoos or public display facilities or through public viewing is not 
a threat to populations. Sport harvest of polar bears in Canada is 
discussed in the harvest section below. For purposes of population 
assessment, no distinction is made between harvest uses for sport or 
subsistence. Take associated with defense of life, scientific research, 
illegal take, and other forms of take are generally included in harvest 
management statistics, so this section also addresses all forms of 
take, including bear-human interactions.

Overview of Harvest

    Polar bears historically have been, and continue to be, an 
important renewable resource for coastal communities throughout the 
Arctic (Lentfer 1976, p. 209; Amstrup and DeMaster 1988, p. 41; 
Servheen et al. 1999, p. 257, Table 14.1; Schliebe et al. 2006a, p. 
72). Polar bears and polar bear hunting remain an important part of 
indigenous peoples' culture, and polar bear hunting is a source of 
pride, prestige, and accomplishment. Polar bears provide a source of 
meat and raw materials for handicrafts, including functional clothing 
such as mittens, boots (mukluks), parka ruffs, and pants (Nageak et al. 
1991, p. 6).
    Prior to the 1950s, most hunting was by indigenous people for 
subsistence purposes. Increased sport hunting in the 1950s and 1960s 
resulted in population declines (Prestrud and Stirling 1994, p. 113). 
International concern about the status of polar bears resulted in 
biologists from the five polar bear range nations forming the Polar 
Bear Specialist Group (PBSG) within the IUCN SSC (Servheen et al. 1999, 
p. 262). The PBSG was largely responsible for the development and 
ratification of the 1973 International Agreement on the Conservation of 
Polar Bears (1973 Polar Bear Agreement) (Prestrud and Stirling 1994, p. 
114) (see detailed discussion under Factor D, ``Inadequacy of Existing 
Regulatory Mechanisms'' below). The 1973 Polar Bear Agreement and the 
actions of the member nations are credited with the recovery of polar 
bears following the previous period of overexploitation.

Harvest Management by Nation

Canada

    Canada manages or shares management responsibility for 13 of the 
world's 19 polar bear populations (Kane Basin, Baffin Bay, Davis 
Strait, Foxe Basin, Western Hudson Bay, Southern Hudson Bay, Gulf of 
Boothia, Lancaster Sound, Norwegian Bay, M'Clintock Channel, Viscount 
Melville Sound, Northern Beaufort Sea, and Southern Beaufort Sea). 
Wildlife management is a shared responsibility of the Provincial and 
Territorial governments. The Federal government (Canadian Wildlife 
Service) has an ongoing research program and is involved in management 
of wildlife populations shared with other jurisdictions, especially 
ones with other nations (e.g., where a polar bear stock ranges across 
an international boundary). To facilitate and coordinate management of 
polar bears, Canada has formed the Federal Provincial Technical 
Committee for Polar Bear Research and Management (PBTC) and the Federal 
Provincial Administrative Committee for Polar Bear Research and 
Management (PBAC). These committees include Provincial, Territorial, 
and Federal representatives who meet annually to review research and 
management activities.
    Polar bears are harvested in Canada by native residents and by 
sport hunters employing native guides. All human-caused mortality 
(i.e., hunting, defense of life, and incidental kills) is included in a 
total allowable harvest. Inuit people from communities in Nunavut, 
Northwest Territories (NWT), Manitoba, Labrador, Newfoundland, and 
Quebec conduct hunting. In Ontario, the Cree and the Inuit can harvest 
polar bears. In Nunavut and NWT, each community obtains an annual 
harvest quota that is based on the best available scientific 
information and monitored through distribution of harvest tags to local 
hunter groups, who work with scientists to set quotas. Native hunters 
may use their harvest tags to guide sport hunts. The majority of sport 
hunters in Canada are U.S. citizens. In 1994 the MMPA was amended to 
allow these hunters to import their trophies into the United States if 
the bears had been taken in a legal manner from sustainably managed 
populations.
    The Canadian system places tight controls on the size and design of 
harvest limits and harvest reporting. Quotas are reduced in response to 
population declines (Aars et al. 2006, p. 11). In 2004, existing polar 
bear harvest practices caused concern when Nunavut identified quota 
increases for 8 populations, 5 of which are shared with other 
jurisdictions (Lunn et al. 2005, p. 3). Quota increases were largely 
based on indigenous knowledge (the Nunavut equivalent of traditional 
ecological knowledge) and the perception that some populations were 
increasing from historic levels. Nunavut did not coordinate these 
changes with adjacent jurisdictions that share management 
responsibility. This action resulted in an increase in the quota of 
allowable harvest from 398 bears in 2003-2004 to 507 bears in 2004-2005 
(Lunn et al. 2005, p. 14, Table 6). Discussions between jurisdictions, 
designed to finalize cooperative agreements regarding the shared 
quotas, continue.

Greenland

    The management of polar bear harvest in Greenland is through a 
system introduced in 1993 that allows only full-time hunters living a 
subsistence lifestyle to hunt polar bears. Licenses are issued annually 
for a small fee contingent upon reporting harvest during the prior 12 
months. Until 2006, no quotas were in place, but harvest statistics 
were collected through Piniarneq, a local reporting program (Born and 
Sonne 2005, p. 137). In January 2006, a new harvest monitoring and 
quota system was implemented (L[oslash]nstrup 2005, p. 133). Annual 
quotas are determined in consideration of international agreements, 
biological advice, user knowledge, and consultation with the Hunting 
Council. However, for the Baffin Bay and Kane Basin populations, which 
are shared with Canada, evaluation of quota levels, harvest levels for 
shared populations occurring in other jurisdictions, and best available 
estimates of population numbers indicate that the quotas and combined 
jurisdictions harvest levels are not sustainable and the enforcement of 
harvest quotas may not be effective

[[Page 28278]]

(Aars et al. 2006). These populations are thought to be reduced and the 
trend is thought to be declining. Greenland is considering the 
allocation of part of the quota for sport hunting (L[oslash]nstrup 
2005, p. 133).

Norway

    Norway and Russia share jurisdiction over the Barents Sea 
population of polar bears. Management in Norway is the responsibility 
of the Ministry of the Environment (Wiig et al. 1995, p. 110). The 
commercial, subsistence, or sport hunting of polar bears in Norway is 
prohibited (Wiig et al. 1995, p. 110). Bears may only be killed in 
self-defense or protection of property, and all kills, including 
``mercy'' kills, must be reported and recorded (Gjertz and Scheie 1998, 
p. 337).

Russia

    The commercial, subsistence, or sport hunting of polar bears in 
Russia is prohibited. Some bears are killed in defense of life, and a 
small number of cubs (1 or 2 per year) have been taken in the past for 
zoos. Despite the 1956 ban on hunting polar bears, illegal harvest is 
occurring in the Chukchi Sea region and elsewhere where there is 
limited monitoring or enforcement (Aars et al. 2007, p. 9; Belikov et 
al. 2005, p. 153). The level of illegal harvest in Russian populations 
is unknown. There is a significant interest in reopening subsistence 
hunting by indigenous people. The combined ongoing illegal hunting in 
Russia and legal subsistence harvest in Alaska is a concern for the 
Chukchi Sea population, which may be in decline (USFWS 2003, p. 1). 
This mutual concern resulted in the United States and Russia signing 
the ``Agreement between the United States of America and the Russian 
Federation on the Conservation and Management of the Alaska-Chukotka 
Polar Bear Population'' (Bilateral Agreement) on October 16, 2000. On 
January 12, 2007, the President of the United States signed into law 
the ``Magnuson-Stevens Fishery Conservation and Management 
Reauthorization Act of 2006.'' This Act added Title V to the MMPA, 
which implements the Bilateral Agreement. On September 22, 2007, the 
governments of the United States and Russian Federation exchanged 
instruments of ratification. Full implementation of the Bilateral 
Agreement is intended to address overharvest, but implementation has 
not yet occurred (Schliebe et al. 2005, p. 75). In the United States, 
Presidential appointment of Commissioners necessary to implement the 
Bilateral Agreement is pending. Accordingly, we have not relied on 
implementation of the Bilateral Agreement in our assessment of the 
threat of overutilization of polar bears (see ``International 
Agreements and Oversight'' section under Factor D below).

United States

    Polar bear subsistence hunting by coastal Alaska Natives has 
occurred for centuries (Lentfer 1976, p. 209). Polar bear hunting and 
the commercial sale of skins took on increasing economic importance to 
Alaskan Natives when whaling began in the 1850s, and a market for pelts 
emerged (Lentfer 1976, p. 209). Trophy hunting using aircraft began in 
the late 1940s. In the 1960s, State of Alaska hunting regulations 
became more restrictive, and in 1972 aircraft-assisted hunting was 
stopped altogether (Lentfer 1976, p. 209). Between 1954 and 1972, an 
average of 222 polar bears was harvested annually, resulting in a 
population decline (Amstrup et al. 1986, p. 246).
    Passage of the MMPA in 1972 established a moratorium on the sport 
or commercial hunting of polar bears in Alaska. However, the MMPA 
exempts harvest, conducted in a nonwasteful manner, of polar bears by 
coastal dwelling Alaska Natives for subsistence and handicraft 
purposes. The MMPA and its implementing regulations also prohibit the 
commercial sale of any marine mammal parts or products except those 
that qualify as authentic articles of handicrafts or clothing created 
by Alaska Natives. The Service cooperates with the Alaska Nanuuq 
Commission, an Alaska Native organization that represents Native 
villages in North and Northwest Alaska on matters concerning the 
conservation and sustainable subsistence use of the polar bear, to 
address polar bear subsistence harvest issues. In addition, for the 
Southern Beaufort Sea population, hunting is regulated voluntarily and 
effectively through an agreement between the Inuvialuit of Canada and 
the Inupiat of Alaska (Brower et al. 2002, p. 371) (see ``International 
Agreements and Oversight'' section under Factor D below). The harvest 
is monitored by the Service's marking and tagging program. Illegal take 
or trade is monitored by the Service's law enforcement program.
    The MMPA was amended in 1994 to allow for the import into the 
United States of sport-hunted polar bear trophies legally taken by the 
importer in Canada. Prior to issuing a permit for import of such 
trophies, the Service must have found that Canada has a monitored and 
enforced sport-hunting program consistent with the purposes of the 1973 
Polar Bear Agreement, and that the program is based on scientifically 
sound quotas ensuring the maintenance of the population at a 
sustainable level. Six populations were approved for import of polar 
bear trophies (62 FR 7302, 64 FR 1529, 66 FR 50843) under regulations 
implementing section 104(c)(5) of the MMPA (50 CFR 18.30). However, as 
of the effective date of the threatened listing, authorization for the 
import of sport hunted polar bear trophies is no longer available under 
section 104(c)(5) of the MMPA.

Harvest Summary

    A thorough review and evaluation of past and current harvest, 
including other forms of removal, for all populations has been 
described in the Polar Bear Status Review (Schliebe et al. 2006a, pp. 
108-127). The Status Review is available on our Marine Mammal website 
(http://alaska.fws.gov/fisheries/mmm/polarbear/issues.htm). Table 2 of 
the Status Review provides a summary of harvest statistics from the 
populations and is included herein as a reference. The total harvest 
and other forms of removal were considered in the summary analysis.
    Five populations (including four that are hunted) have no estimate 
of potential risk from overharvest, since adequate demographic 
information necessary to conduct a population viability analysis and 
risk assessment are not available (see Table 1 below). For one of the 
populations, Chukchi Sea, severe overharvest is suspected to have 
occurred during the past 10-15 years, and anecdotal information 
suggests the population is in decline (Aars et al. 2006, pp. 34-35). 
The Chukchi Sea, Baffin Bay, Kane Basin, and Western Hudson Bay 
populations may be overharvested (Aars et al. 2006, pp. 40, 44-46). In 
other populations, including East Greenland and Davis Strait, 
substantial harvest occurs annually in the absence of scientifically 
derived population estimates (Aars et al. 2006, pp. 39, 46). 
Considerable debate has occurred regarding the recent changes in 
population estimates based on indigenous or local knowledge (Aars et 
al. 2006, p. 57) and subsequent quota increases for some populations in 
Nunavut (Lunn et al. 2005, p. 20). The PBSG (Aars et al. 2006, p. 57), 
by resolution, recommended that ``polar bear harvest can be increased 
on the basis of local and traditional knowledge only if supported by 
scientifically collected information.'' Increased polar bear 
observations along the coast may be attributed to changes in bear 
distribution due to lack of suitable ice habitat rather than to 
increased

[[Page 28279]]

population size (Stirling and Parkinson 2006, p. 266). Additional data 
are needed to reconcile these differing interpretations.
    As discussed in Factor A, Amstrup et al. (2007, p.30) used a first-
generation BM model to forecast the range-wide status of polar bears 
during the 21st century, factoring in a number of stressors, including 
intentional take or harvest. The authors conducted a sensitivity 
analysis to determine the importance and influence of the stressors on 
the population forecast. Their analysis indicated that intentional take 
was the 4th ranked .potential stressor, and could exacerbate the 
effects of habitat loss in the future. Because of the preliminary 
nature of the BM results, we are more confident in the general 
direction and magnitude of the projected outcomes rather than the 
actual numerical probabilities associated with each outcome. 
Nonetheless, the relatively high ranking for this stressor indicates 
that effective management of hunting and evaluation of sustainable 
harvest levels will continue to be important to minimize effects for 
populations experiencing increased stress.
[GRAPHIC] [TIFF OMITTED] TR15MY08.012

Bear-Human Interactions

    Polar bears come into conflict with humans when they scavenge for 
food at sites of human habitation, and also because they occasionally 
prey or attempt to prey upon humans (Stirling 1988, p. 182). ``Problem 
bears,'' the bears most associated with human conflicts, are most often 
subadult bears that are inexperienced hunters and, therefore, that 
scavenge more frequently than adult bears (Stirling 1988, p. 182). 
Following subadults, females with cubs are most likely to interact with 
humans, because females with cubs are likely to be thinner and hungrier 
than single adult bears, and starving bears are more likely to interact 
with humans in their pursuit of food (Stirling 1988, p. 182). For 
example, in Churchill, Manitoba, Canada, an area of high polar bear 
use, the occurrence of females with cubs feeding at the town's garbage 
dump in

[[Page 28280]]

the fall increased during years when bears came ashore in poorer 
condition (Stirling 1988, p. 182). Other factors that may influence 
bear-human encounters include increased land use activities, increased 
human populations in areas of high polar bear activity, increased polar 
bear concentrations on land, and earlier polar bear departure from ice 
habitat to terrestrial habitats.
    Increased bear-human interactions and defense-of-life kills may 
occur under predicted climate change scenarios where more bears are on 
land and in contact with human settlements (Derocher et al. 2004, p. 
169). Direct interactions between people and bears in Alaska have 
increased markedly in recent years, and this trend is expected to 
continue (Amstrup 2000, p. 153). Since the late 1990s, the timing of 
complete ice formation in the fall has occurred later in November or 
early December than it formerly did (September and October), resulting 
in an increased amount of time polar bears spend on land. This 
consequently increases the probability of bear-human interactions 
occurring in coastal villages. Adaptive management programs that focus 
on the development of community or ecotourism based polar bear-human 
interaction plans (that include polar bear patrols, deterrent and 
hazing programs, efforts to manage and minimize sources of attraction, 
and education about polar bear behavior and ecology) are ongoing in a 
number of Alaska North Slope communities and should be expanded or 
further developed for other communities in the future. In four Canadian 
populations-Western Hudson Bay, Foxe Basin, Baffin Bay, and Davis 
Strait-Inuit hunters reported seeing more bears in recent years around 
settlements, hunting camps, and sometimes locations where they had not 
(or only rarely) been seen before, resulting in an increase in threats 
to human life and damage to property (Stirling and Parkinson 2006, p. 
262).
    As discussed in Factor A, Amstrup et al. (2007, p.30) used a first-
generation BM model to forecast the range-wide status of polar bears 
during the 21st century, factoring in a number of stressors, including 
bear-human interactions. The authors conducted a sensitivity analysis 
to determine the importance and influence of the stressors on the 
population forecast. Their analysis indicated that bear-human 
interactions ranked 7th of potential stressors. Because of the 
preliminary nature of the BM results, we are more confident in the 
general direction and magnitude of the projected outcomes rather than 
the actual numerical probabilities associated with each outcome. 
Although this factor's singular contribution to a declining population 
trend was relatively small, it could operate with other mortality 
factors (such as harvest) in the future to exacerbate the effects of 
habitat loss. Thus, bear-human interactions should be monitored, and 
may require additional management actions in the future.

Conclusion for Factor B

Rationale

    Polar bears are harvested in Canada, Alaska, Greenland, and Russia. 
Active harvest management or reporting programs are in place for 
populations in Canada, Greenland, and Alaska. Principles of sustainable 
yield are instituted through harvest quotas or guidelines for a number 
of Canadian populations. Other forms of removal, such as defense-of-
life take are considered through management actions by the responsible 
jurisdictions. Hunting or killing polar bears is illegal in Russia, 
although an unknown level of harvest occurs, and harvest impacts on 
Russian populations are generally unknown. While overharvest is 
occurring for some populations, laws and regulations for most 
management programs have been instituted and are flexible enough to 
allow adjustments in order to ensure that harvests are sustainable. 
These actions are largely viewed as having succeeded in reversing 
widespread overharvests by many jurisdictions that resulted in 
population depletion during the period prior to signing of the 
multilateral 1973 Polar Bear Agreement (Prestrud and Stirling 1994) see 
additional discussion under Factor D below). For the internationally-
shared populations in the Chukchi Sea, Baffin Bay, Kane Basin, and 
Davis Strait, conservation agreements have been developed (United 
States-Russia) or are in development (Canada-Greenland), but in making 
our finding we have not relied on agreements that have not been 
implemented.
    We realize that management agencies will be challenged in the 
future with managing populations that are declining and under stress 
from loss of sea ice. We also note that the sensitivity anlaysis 
conducted by Amstrup et al. (2007, pp. 35, 58) suggests that, for some 
populations, the effects of habitat and environmental changes will far 
outweigh the effects of harvest, and consequently, that harvest 
regulation may have little effect on the ultimate population outcome. 
For other populations affected to a lesser degree by environmental 
changes and habitat impacts, effective implementation of existing 
regulatory mechanisms is necessary to address issues related to 
overutilization.

Determination for Factor B

    We have evaluated the best available scientific and commercial 
information on the utilization of polar bears for commercial, 
recreational, scientific, or educational purposes. Harvest, increased 
bear-human interaction levels, defense-of-life take, illegal take, and 
take associated with scientific research live-capture programs are 
occurring for several populations. We have determined that harvest is 
likely exacerbating the effects of habitat loss in several populations. 
In addition, polar bear mortality from harvest and negative bear-human 
interactions may in the future approach unsustainable levels for 
several populations, especially those experiencing nutritional stress 
or declining population numbers as a consequence of habitat change. The 
PBSG (Aars et al. 2006, p. 57), through resolution, urged that a 
precautionary approach be instituted when setting harvest limits in a 
warming Arctic environment. Continued efforts are necessary to ensure 
that harvest or other forms of removal do not exceed sustainable 
levels. We find, however, that overutilization does not currently 
threaten the polar bear throughout all or a significant portion of its 
range.

Factor C. Disease and Predation

Disease

    The occurrence of diseases and parasites in polar bears is rare 
compared to other bears, with the exception of the presence of 
Trichinella larvae, Trichinella has been documented in polar bears 
throughout their range, and, although infestations can be quite high, 
they are normally not fatal (Rausch 1970, p. 360; Dick and Belosevic 
1978, p. 1,143; Larsen and Kjos-Hanssen 1983, p. 95; Taylor et al. 
1985, p. 303; Forbes 2000, p. 321). Although rabies is commonly found 
in Arctic foxes, there has been only one documented case in polar bears 
(Taylor et al. 1991, p. 337). Morbillivirus has been documented in 
polar bears from Alaska and Russia (Garner et al. 2000, p. 477; C. 
Kirk, University of Alaska, Fairbanks, pers. comm. 2006). Antibodies to 
the protozoan parasite, Toxoplasma gondii, were found in Alaskan polar 
bears; whether this is a health concern for polar bears is unknown (C. 
Kirk, University of Alaska, Fairbanks, pers. comm. 2006).

[[Page 28281]]

    Whether polar bears are more susceptible to new pathogens due to 
their lack of previous exposure to diseases and parasites is also 
unknown. Many different pathogens and viruses have been found in seal 
species that are polar bear prey (Duignan et al. 1997, p. 7; Measures 
and Olson 1999, p. 779; Dubey et al. 2003, p. 278; Hughes-Hanks et al. 
2005, p. 1,226), so the potential exists for transmission of these 
diseases to polar bears. . As polar bears become more nutritionally 
stressed, they may eat more of the intestines and internal organs of 
their prey than they presently do, thus increasing potential exposure 
to parasites and viruses (Derocher et al. 2004, p. 170; Amstrup et al. 
2006b, p. 3). In addition, new pathogens may expand their range 
northward from more southerly areas under projected climate change 
scenarios (Harvell et al. 2002, p. 60). A warming climate has been 
associated with increases in pathogens in other marine organisms 
(Kuiken et al. 2006, p. 322).
    Amstrup et al. (2007, p. 87) considered a host of potential 
stressors, including diseases and parasites, in their status evaluation 
of polar bears. The influence of parasites and disease agents evaluated 
in the sensitivity analysis ranked 8th, and made very minor 
contributions to the projected population status. The authors note, 
however, that the potential effect of disease and parasites on polar 
bears would likely increase if the climate continues to warm (Amstrup 
et al. 2007, p. 21). Parasitic agents that have developmental stages 
outside the bodies of warm-blooded hosts (e.g., nematodes) will likely 
benefit from the warmer and wetter weather projected for the Arctic 
(Macdonald et al. 2005). Significant impacts from such parasites on 
some Arctic ungulates have been noted. Improved conditions for such 
parasites already have had significant impacts on some terrestrial 
mammals (Kutz et al. 2001, p. 771; Kutz et al. 2004). Bacterial 
parasites also are likely to benefit from a warmer and wetter Arctic. 
Although increases in disease and parasite agents have not yet been 
reported in polar bears, they are anticipated, if temperatures continue 
to warm as projected. Amstrup et al. (2007, p. 31) also indicated that 
diseases and parasites could operate to exacerbate the effects of 
habitat loss. Continued monitoring of pathogens and parasites in polar 
bears is appropriate.

Intraspecific Predation

    Intraspecific killing has been reported among all North American 
bear species (Derocher and Wiig 1999, p. 307; Amstrup et al. 2006b, p. 
1). Reasons for intraspecific predation in bear species are poorly 
understood but thought to include nutrition, and enhanced breeding 
opportunities in the case of predation on cubs. Although occurrences of 
infanticide by male polar bears have been well documented (Hansson and 
Thomassen 1983, p. 248; Larsen 1985, p. 325; Taylor et al. 1985, p. 
304; Derocher and Wiig 1999, p. 307), this activity accounts for a 
small percentage of the cub mortality.
    Cannibalism has also been documented in polar bears (Derocher and 
Wiig 1999, p. 307; Amstrup et al. 2006b, p. 1). Amstrup et al. (2006b, 
p. 1) observed three instances of cannibalism in the southern Beaufort 
Sea during the spring of 2004; two involved adult females (one an 
unusual mortality of a female in a den) and third involved a yearling. 
This is notable because, throughout a combined 58 years of research, 
there are no similar observations recorded. Active stalking or hunting 
preceded the attacks, and all three of the killed bears were wholly or 
partly consumed. Adult males were believed to be the predator in both 
attacks. Amstrup et al. (2006b, p. 43) indicated that in general a 
greater proportion of polar bears in the area where the predation 
events occurred were in poorer physical condition compared to bears 
captured in other areas. The authors hypothesized that large adult 
males may be the first to show effects of nutritional stress which is 
expected to occur first in more southerly areas, due to significant ice 
retreat (Skinner et al. 1988, p. 3; Comiso and Parkinson 2004, p. 43; 
Stroeve et al. 2005, p. 1) . Adult males may be the first to show the 
effects of nutritional stress because they feed little during the 
spring mating season and enter the summer in poorer condition than 
other sex/age classes. Derocher and Wiig (1999, p. 308) documented a 
similar intraspecific killing and consumption of another polar bear in 
Svalbard, Norway, which was attributed to relatively high population 
densities and food shortages. Taylor et al. (1985, p. 304) documented 
that a malnourished female killed and consumed her own cubs, and Lunn 
and Stenhouse (1985, p. 1,516) found an emaciated male consuming an 
adult female polar bear. The potential importance of cannibalism and 
infanticide for polar bear population regulation is unknown. However, 
given our current knowledge of disease and predation, we do not believe 
that these factors are currently having population-level effects.
    Another form of intraspecific stress is cross-breeding, or 
hybridization. The first documented instance of cross-breeding in the 
wild was reported in the spring of 2006. Rhymer and Simberloff (1996, 
pp. 83-84) express concerns for cross-breeding in the wild, noting that 
habitat modification contributing to cross breeding may cause the 
break-down of reproductive isolation between native species, leading to 
mixing of gene pools and potential loss of genotypically distinct 
populations. The authors generally viewed hybridization through 
introgression (defined as gene flow between populations through 
hybridization when hybrids cross back to one of the parental 
populations) as a threat to plant and animal taxa, particularly for 
morphologically well-defined and evolutionarily isolated taxa. Cross-
breeding in the wild is thought to be extremely rare, but cross-
breeding may pose additional concerns for population and species 
viability in the future should the rate of occurrence increase.

Conclusion for Factor C

Rationale

    Disease pathogen titers are present in polar bears; however, no 
epizootic outbreaks have been detected. In addition, forms of 
intraspecific stress and cannibalism are known to be present with bear 
species and within polar bears. For polar bears, there is no indication 
that these stressors have operated to influence population levels in 
the past. Cannibalism is an indication of intraspecific stress, however 
we do not believe it has resulted in population level effects.

Determination for Factor C

    We have evaluated the best available scientific information on 
disease and predation, and have determined that disease and predation 
(including intraspecific predation) do not threaten the species 
throughout all or any significant portion of its range. Potential for 
disease outbreaks, an increased possibility of pathogen exposure from 
changed diet or the occurrence of new pathogens that have moved 
northward with a warming environment, and increased mortality from 
cannibalism all warrant continued monitoring and may become more 
significant threat factors in the future for polar bear populations 
experiencing nutritional stress or declining population numbers.

Factor D. Inadequacy of Existing Regulatory Mechanisms

    Regulatory mechanisms directed specifically at managing many of the 
threats to polar bears, such as overharvest or disturbance, exist in 
all of the countries states where the species

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occurs, as well as between (bilateral and multilateral) range 
countries.

IUCN/SSC Polar Bear Specialist Group

    The Polar Bear Specialist Group (PBSG) is not a regulatory 
authority nor do they provide any regulatory mechanisms. However, the 
PBSG contributed significantly to the negotiation and development of 
the International Agreement on the Conservation of Polar Bears (1973 
Polar Bear Agreement), and has been instrumental in monitoring the 
worldwide status of polar bear populations. Therefore, we believe a 
discussion of the PBSG is relevant to a current understanding of the 
status of polar bears worldwide. We did not rely on the PBSG or any 
actions of the PBSG for determining the status of the polar bear under 
the Act.
    The PBSG operates under the IUCN Species Survival Commission (SSC), 
and was formed in 1968. The PBSG meets periodically at 3-to 5-year 
intervals in compliance with Article VII of the 1973 Polar Bear 
Agreement; said article instructs member parties to conduct national 
research programs on polar bears, particularly research relating to the 
conservation and management of the species and, as appropriate, 
coordinate such research with the research carried out by other 
parties, consult with other parties on management of migrating polar 
bear populations, and exchange information on research and management 
programs, research results, and data on bears taken. The PBSG first 
evaluated the status of all polar bear populations in 1980. In 1993, 
1997, and 2001, the PBSG conducted circumpolar status assessments of 
polar bear populations, and the results of those assessments were 
published as part of the proceedings of the relevant PBSG meeting. The 
PBSG conducted its fifth polar bear status assessment in June 2005.
    The PBSG also evaluates the status of polar bears under the IUCN 
Red List criteria. Previously, polar bears were classified under the 
IUCN Red List program as: ``Less rare but believed to be threatened/
requires watching'' (1965); ``Vulnerable'' (1982, 1986, 1988, 1990, 
1994); and ``Lower Risk/Conservation Dependent'' (1996). During the 
2005 PBSG working group meeting, the PBSG re-evaluated the status of 
polar bears and unanimously agreed that a status designation of 
``Vulnerable'' was warranted.

International Agreements and Oversight

International Agreement on the Conservation of Polar Bears

    Canada, Denmark (on behalf of Greenland), Norway, the Russian 
Federation, and the United States are parties to the Agreement on the 
Conservation of Polar Bears (1973 Polar Bear Agreement) signed in 1973; 
by 1976, the Agreement was ratified by all parties. The 1973 Polar Bear 
Agreement requires the parties to take appropriate action to protect 
the ecosystem of which polar bears are a part, with special attention 
to habitat components such as denning and feeding sites and migration 
patterns, and to manage polar bear populations in accordance with sound 
conservation practices based on the best available scientific data. The 
1973 Polar Bear Agreement relies on the efforts of each party to 
implement conservation programs and does not preclude a party from 
establishing additional controls (Lentfer 1974, p. 1).
    The 1973 Polar Bear Agreement is viewed as a success in that polar 
bear populations recovered from excessive harvests and severe 
population reductions in many areas (Prestrud and Stirling 1994). At 
the same time, implementation of the terms of the 1973 Polar Bear 
Agreement varies across the member parties. Efforts are needed to 
improve current harvest management practices, such as restricting 
harvest of females and cubs, establishing sustainable harvest limits, 
and controlling illegal harvests (Derocher et al. 1998, pp. 47-48). In 
addition, a lack of protection of key habitats by member parties, with 
few notable exceptions for some denning areas, is a weakness (Prestrud 
and Stirling 1994, p. 118).

Inupiat-Inuvialuit Agreement for the Management of Polar Bears of the 
Southern Beaufort Sea

    In January 1988, the Inuvialuit of Canada and the Inupiat of 
Alaska, groups that both harvest polar bears for cultural and 
subsistence purposes, signed a management agreement for polar bears of 
the southern Beaufort Sea. This agreement, based on the understanding 
that the two groups harvested animals from a single population shared 
across the international boundary, provides a joint responsibility for 
conservation and harvest practices (Treseder and Carpenter 1989, p. 4; 
Nageak et al. 1991, p. 341). Provisions of the agreement include: 
annual quotas (which may include problem kills); hunting seasons; 
protection of bears in dens or while constructing dens, and protection 
of females accompanied by cubs and yearlings; collection of specimens 
from killed bears to facilitate monitoring of the sex and age 
composition of the harvest; agreement to meet annually to exchange 
information on research and management and to set priorities; agreement 
on quotas for the coming year; and prohibition of hunting with aircraft 
or large motorized vessels and of trade in products taken in violation 
of the agreement. In Canada, recommendations and decisions from the 
Commissioners are then implemented through Community Polar Bear 
Management Agreements, Inuvialuit Settlement Region Community Bylaws, 
and NWT Big Game Regulations. In the United States, this agreement is 
implemented at the local level. Adherence to the agreement's terms in 
Alaska is voluntary, and levels of compliance may vary. There are no 
Federal, State, or local regulations that limit the number or type 
(male, female, cub) of polar bear that may be taken. Brower et al. 
(2002) analyzed the effectiveness of the Inupiat-Inuvialuit Agreement, 
and found that it had been successful in maintaining the total harvest 
and the proportion of females in the harvest within sustainable levels. 
The authors noted the need to improve harvest monitoring in Alaska and 
increase awareness of the need to prevent overharvest of females for 
both countries.

Agreement between the United States of America and the Russian 
Federation on the Conservation and Management of the Alaska-Chukotka 
Polar Bear Population

    On October 16, 2000, the United States and the Russian Federation 
signed a bilateral agreement for the conservation and management of 
polar bear populations shared between the two countries. The Agreement 
between the United States of America and the Russian Federation on the 
Conservation and Management of the Alaska-Chukotka Polar Bear 
Population (Bilateral Agreement) expands upon the progress made through 
the multilateral 1973 Polar Bear Agreement by implementing a unified 
conservation program for this shared population. The Bilateral 
Agreement reiterates requirements of the 1973 Polar Bear Agreement and 
includes restrictions on harvesting denning bears, females with cubs or 
cubs less than 1 year old, and prohibitions on the use of aircraft, 
large motorized vessels, and snares or poison for hunting polar bears. 
The Bilateral Agreement does not allow hunting for commercial purposes 
or commercial

[[Page 28283]]

uses of polar bears or their parts. It also commits the parties to the 
conservation of ecosystems and important habitats, with a focus on 
conserving polar bear habitats such as feeding, congregating, and 
denning areas. The Russian government indicates that it is prepared to 
implement the Bilateral Agreement. On December 9, 2006, the Congress of 
the United States passed the ``United States--Russia Polar Bear 
Conservation and Management Act of 2006.'' This Act provides the 
necessary authority to regulate and manage the harvest of polar bears 
from the Chukchi Sea population, an essential conservation measure. 
Ratification documents have been exchanged between the countries, but 
the United States has yet to designate representatives to the 
Commission, and we did not rely on this treaty in our assessment as it 
is not formally implemented. Implementation of the Act will provide 
numerous conservation benefits for this population, however it does not 
provide authority or mechanisms to address ongoing loss of sea ice.

Convention on International Trade in Endangered Species of Wild Fauna 
and Flora (CITES)

    The Convention on International Trade in Endangered Species of Wild 
Fauna and Flora (CITES) is a treaty aimed at protecting species at risk 
from international trade. The CITES regulates international trade in 
animals and plants by listing species in one of its three appendices. 
The level of monitoring and regulation to which an animal or plant 
species is subject depends on the appendix in which the species is 
listed. Appendix I includes species threatened with extinction that are 
or may be affected by trade; trade of Appendix I species is only 
allowed in exceptional circumstances. Appendix II includes species not 
necessarily now threatened with extinction, but for which trade must be 
regulated in order to avoid utilization incompatible with their 
survival. Appendix III includes species that are subject to regulation 
in at least one country, and for which that country has asked other 
CITES Party countries for assistance in controlling and monitoring 
international trade in that species.
    Polar bears were listed in Appendix II of CITES on July 7, 1975. As 
such, CITES parties must determine, among other things, that any polar 
bear, polar bear part, or product made from polar bear was legally 
obtained and that the export will not be detrimental to the survival of 
the species, prior to issuing a permit authorizing the export of the 
animal, part, or product. The CITES does not itself regulate take or 
domestic trade of polar bears; however, through its process of 
monitoring trade in wildlife species and requisite findings prior to 
allowing international movement of listed species and monitoring 
programs, the CITES is effective in ensuring that the international 
movement of listed species does not contribute to the detriment of 
wildlife populations. All polar bear range states are members to the 
CITES and have in place the CITES-required Scientific and Management 
Authorities. The Service therefore has determined that the CITES is 
effective in regulating the international trade in polar bear, or polar 
bear parts or products, and provides conservation measures to minimize 
those potential threats to the species.

Domestic Regulatory Mechanisms

United States

Marine Mammal Protection Act of 1972, as amended

    The Marine Mammal Protection Act of 1972, as amended (16 U.S.C. 
1361 et seq.) (MMPA) was enacted to protect and conserve marine mammals 
so that they continue to be significant functioning elements of the 
ecosystem of which they are a part. The MMPA set forth a national 
policy to prevent marine mammal species or population stocks from 
diminishing to the point where they are no longer a significant 
functioning element of the ecosystems.
    The MMPA places an emphasis on habitat and ecosystem protection. 
The habitat and ecosystem goals set forth in the MMPA include: (1) 
Management of marine mammals (including of polar bears) to ensure they 
do not cease to be a significant element of the ecosystem to which they 
are a part; (2) protection of essential habitats, including rookeries, 
mating grounds, and areas of similar significance ``from the adverse 
effects of man's action''; (3) recognition that marine mammals ``affect 
the balance of marine ecosystems in a manner that is important to other 
animals and animal products,'' and that marine mammals and their 
habitats should therefore be protected and conserved; and (4) direction 
that the primary objective of marine mammal management is to maintain 
``the health and stability of the marine ecosystem.'' Congressional 
intent to protect marine mammal habitat is also reflected in the 
definitions section of the MMPA. The terms ``conservation'' and 
``management'' of marine mammals are specifically defined to include 
habitat acquisition and improvement.
    The MMPA established a general moratorium on the taking and 
importing of marine mammals and a number of prohibitions, which are 
subject to a number of exceptions. Some of these exceptions include 
take for scientific purposes, for purposes of public display, for 
subsistence use by Alaska Natives, and unintentional incidental take 
coincident with conducting otherwise lawful activities. The Service, 
prior to issuing a permit authorizing the taking or importing of a 
polar bear, or a polar bear part or product, for scientific or public 
display purposes submits each request to a rigorous review, including 
an opportunity for public comment and consultation with the U.S. Marine 
Mammal Commision (MMC), as described at 50 CFR 18.31. In addition, in 
1994, Congress amended the MMPA to allow for the import of polar bear 
trophies taken in Canada for personal use providing certain 
requirements are met. Import permits may only be issued to hunters that 
are citizens of the United States for trophies they have legally taken 
from those Canadian polar bear populations the Service has approved as 
meeting the MMPA requirements, as described at 50 CFR 18.30. The 
Service has determined that there is sufficient rigor under the 
regulations at 50 CFR 18.30 and 18.31 to ensure that any activities so 
authorized are consistent with the conservation of this species and are 
not a threat to the species.
    Take is defined in the MMPA to include the ``harassment'' of marine 
mammals. ``Harassment'' includes any act of pursuit, torment, or 
annoyance that ``has the potential to injure a marine mammal or marine 
mammal stock in the wild'' (Level A harassment), or ``has the potential 
to disturb a marine mammal or marine mammal stock in the wild by 
causing disruption of behavioral patterns, including, but not limited 
to, migration, breathing, nursing, breeding, feeding, or sheltering'' 
(Level B harassment).
    The Secretaries of Commerce and of the Interior have primary 
responsibility for implementing the MMPA. The Department of Commerce, 
through the National Oceanic and Atmospheric Administration (NOAA), has 
authority with respect to whales, porpoises, seals, and sea lions. The 
remaining marine mammals, including polar bears, walruses, sea otters, 
dugongs, and manatees are managed by the Department of the Interior 
through the U.S. Fish and Wildlife Service. Both agencies are ``* * * 
responsible for the promulgation of regulations, the issuance of 
permits, the conduct of scientific research, and enforcement as

[[Page 28284]]

necessary to carry out the purposes of [the MMPA].''
    Citizens of the United States who engage in a specified activity 
other than commercial fishing (which is specifically and separately 
addressed under the MMPA) within a specified geographical region may 
petition the Secretary of the Interior to authorize the incidental, but 
not intentional, taking of small numbers of marine mammals within that 
region for a period of not more than five consecutive years (16 U.S.C. 
1371(a)(5)(A)). The Secretary ``shall allow'' the incidental taking if 
the Secretary finds that ``the total of such taking during each five-
year (or less) period concerned will have no more than a negligible 
impact on such species or stock and will not have an unmitigable 
adverse impact on the availability of such species or stock for taking 
for subsistence uses.'' If the Secretary makes the required findings, 
the Secretary also prescribes regulations that specify (1) permissible 
methods of taking, (2) means of affecting the least practicable adverse 
impact on the species, their habitat, and their availability for 
subsistence uses, and (3) requirements for monitoring and reporting. 
The regulatory process does not authorize the activities themselves, 
but authorizes the incidental take of the marine mammals in conjunction 
with otherwise legal activities.
    Similar to promulgation of incidental take regulations, the MMPA 
also established an expedited process by which citizens of the United 
States can apply for an authorization to incidentally take small 
numbers of marine mammals where the take will be limited to harassment 
(16 U.S.C. 1371(a)(5)(D)). These authorizations are limited to one year 
and as with incidental take regulations, the Secretary must find that 
the total of such taking during the period will have no more than a 
negligible impact on such species or stock and will not have an 
unmitigable adverse impact on the availability of such species or stock 
for taking for subsistence uses. The Service refers to these 
authorizations as Incidental Harassment Authorizations.
    Examples and descriptions of how the Service has analyzed the 
effects of oil and gas activities and applied the general provisions of 
the MMPA described above to polar bear conservation programs in the 
Beaufort and Chukchi Seas are decribed in the Range Wide Status Review 
of the Polar Bear (Ursus maritimus) (Schliebe et al. 2006a). These 
regulations include an evaluation of the cumulative effects of oil and 
gas industry activities on polar bears from noise, physical 
obstructions, human encounters, and oil spills. The likelihood of an 
oil spill occurring and the risk to polar bears is modeled 
quantitatively and factored into the evaluation. The results of 
previous industry monitoring programs, and the effectiveness of past 
detection and deterrent programs that have a beneficial record of 
protecting polar bears, as well as providing for the safety of oil 
field workers, are also considered. Based on the low likelihood of an 
oil spill occurring and the effectiveness of industry mitigation 
measures within the Beaufort Sea region, the Service has found that oil 
and gas industry activities have not affected the rates of recruitment 
or survival for the polar bear populations over the period of the 
regulations.
    General operating conditions in specific authorizations include the 
following: (1) Protection of pregnant polar bears during denning 
activities (den selection, birthing, and maturation of cubs) in known 
and confirmed denning areas; (2) restrictions on industrial activities, 
areas, time of year; and (3) development of a site-specific plan of 
operation and a site-specific polar bear interaction plan. Additional 
requirements may include: pre-activity surveys (e.g., aerial surveys, 
infra-red thermal aerial surveys, or polar bear scent-trained dogs) to 
determine the presence or absence of dens or denning activity and, in 
known denning areas, enhanced monitoring or flight restrictions, such 
as minimum flight elevations. These and other safeguards and 
coordination with industry have served to minimize industry effects on 
polar bears.

Outer Continental Shelf Lands Act

    The Outer Continental Shelf Lands Act (43 U.S.C. 1331 et seq.) 
(OCSLA) established Federal jurisdiction over submerged lands on the 
Outer Continental Shelf (OCS) seaward of the State boundaries (3-mile 
limit) in order to expedite exploration and development of oil/gas 
resources on the OCS in a manner that minimizes impact to the living 
natural resources within the OCS. Implementation of OCSLA is delegated 
to the Minerals Management Service (MMS) of the Department of the 
Interior. The OCS projects that could adversely impact the Coastal Zone 
are subject to Federal consistency requirements under terms of the 
Coastal Zone Management Act, as noted below. The OCSLA also mandates 
that orderly development of OCS energy resources be balanced with 
protection of human, marine, and coastal environments. The OCSLA does 
not itself regulate the take of polar bears, although through 
consistency determinations it helps to ensure that OCS projects do not 
adversely impact polar bears or their habitats.

Oil Pollution Act of 1990

    The Oil Pollution Act of 1990 (33 U.S.C. 2701) established new 
requirements and extensively amended the Federal Water Pollution 
Control Act (33 U.S.C. 1301 et. seq.) to provide enhanced capabilities 
for oil spill response and natural resource damage assessment by the 
Service. It requires us to consult on developing a fish and wildlife 
response plan for the National Contingency Plan, input to Area 
Contingency Plans, review of Facility and Tank Vessel Contingency 
Plans, and to conduct damage assessments associated with oil spills.

Coastal Zone Management Act

    The Coastal Zone Management Act of 1972 (16 U.S.C. 1451 et seq.) 
(CZMA) was enacted to ``preserve, protect, develop, and where possible, 
to restore or enhance the resources of the Nation's coastal zone.'' The 
CZMA provides for the submission of a State program subject to Federal 
approval. The CZMA requires that Federal actions be conducted in a 
manner consistent with the State's CZM plan to the maximum extent 
practicable. Federal agencies planning or authorizing an activity that 
affects any land or water use or natural resource of the coastal zone 
must provide a consistency determination to the appropriate State 
agency. The CZMA applies to polar bear habitats of northern and western 
Alaska. The North Slope Borough and Alaska Coastal Management Programs 
assist in protection of polar bear habitat through the project review 
process. The CZMA does not itself regulate the take of polar bears, 
and, overall, is not determined to be effective at this time in 
addressing the threats identified in the five factor analysis.

Alaska National Interest Lands Conservation Act

    The Alaska National Interest Lands Conservation Act of 1980 (16 
U.S.C. 3101 et seq.) (ANILCA) created or expanded National Parks and 
National Wildlife Refuges in Alaska, including the expansion of the 
Arctic National Wildlife Refuge (NWR). One of the establishing purposes 
of the Arctic NWR is to conserve polar bears. Section 1003 of ANILCA 
prohibits production of oil and gas in the Arctic NWR, and no leasing 
or other development leading to production of oil and gas may take 
place unless authorized by an Act of Congress. Most of the Arctic NWR 
is a federally

[[Page 28285]]

designated Wilderness, but the coastal plain of Arctic NWR, which 
provides important polar bear denning habitat, does not have Wilderness 
status. The ANILCA does not itself regulate the take of polar bears, 
although through its designations it has provided recognition of, and 
various levels of protection for, polar bear habitat. In the case of 
polar bear habitat, the Bureau of Land Management (BLM) is responsible 
for vast land areas on the North Slope, including the National 
Petroleum Reserve, Alaska (NPRA). Habitat suitable for polar bear 
denning and den sites have been identified within NPRA. The BLM 
considers fish and wildlife values under its multiple use mission in 
evaluating land use authorizations and prospective oil and gas leasing 
actions. Provisions of the MMPA regarding the incidental take of polar 
bears on land areas and waters within the jurisdiction of the United 
States continue to apply to activities conducted by the oil and gas 
industry on BLM lands.

Marine Protection, Research and Sanctuaries Act

    The Marine Protection, Research and Sanctuaries Act (33 U.S.C. 1401 
et seq.) (MPRSA) was enacted in part to ``prevent or strictly limit the 
dumping into ocean waters of any material that would adversely affect 
human health, welfare, or amenities, or the marine environment, 
ecological systems, or economic potentialities.'' The MPRSA does not 
itself regulate the take of polar bears. There are no designated marine 
sanctuaries within the range of the polar bear.

Canada

    Canada's constitutional arrangement specifies that the Provinces 
and Territories have the authority to manage terrestrial wildlife, 
including the polar bear, which is not defined as a marine mammal in 
Canada. The Canadian Federal Government is responsible for CITES-
related programs and provides both technical (long-term demographic, 
ecosystem, and inventory research) and administrative (Federal-
Provincial Polar Bear Technical Committee (PBTC), Federal-Provincial 
Polar Bear Administrative Committee (PBAC), and the National Database) 
support to the Provinces and Territories. The Provinces and Territories 
have the ultimate authority for management, although in several areas, 
the decision-making process is shared with aboriginal groups as part of 
the settlement of land claims. Regulated hunting by aboriginal people 
is permissible under Provincial and Territorial statutes (Derocher et 
al. 1998, p. 32) as described in Factor B.
    In Manitoba, most denning areas have been protected by inclusion 
within the boundaries of Wapusk National Park. In Ontario, some denning 
habitat and coastal summer sanctuary habitat are included in Polar Bear 
Provincial Park. Some polar bear habitat is included in the National 
Parks and National Park Reserves and territorial parks in the Northwest 
Territories, Nunavut, and Yukon Territory (e.g., Herschel Island). 
While these parks and preserves provide some protection for terrestrial 
habitat, subsistence hunting activities are allowed in these areas. 
Additional habitat protection measures in Manitoba include restrictions 
on harassment and approaching dens and denning bears, and a land use 
permit review that considers potential impacts of land use activities 
on wildlife (Derocher et al. 1998, p. 35). The measures adopted by the 
Government of Manitoba have been effective on a site-specific basis. In 
addition, the Government of Manitoba has recently listed the polar bear 
as a threatened species in that province; however, we have no 
information on whether this designation provides any additional 
regulatory protection for the species.

Species at Risk Act

    Canada's Species at Risk Act (SARA) became law on December 12, 
2002, and went into effect on June 1, 2004 (Walton 2004, p. M1-17). 
Prior to SARA, Canada's oversight of species at risk was conducted 
through the Committee on the Status of Endangered Wildlife in Canada 
(COSEWIC) which continues to function under SARA and through the 
Ministry of Environment. COSEWIC evaluates species status and provides 
recommendations to the Minister of the Environment, who makes final 
listing decisions and identifies species-specific management actions. 
The SARA provides a number of protections for wildlife species placed 
on the List of Wildlife Species at Risk, or ``Schedule 1'' (SARA 
Registry 2005). The listing criteria used by COSEWIC are based on the 
2001 IUCN Red List assessment criteria (Appendix 3). Currently, under 
SARA the polar bear is designated as a Schedule 3 species, ``Species of 
Special Concern,'' awaiting re-assessment and public consultation for 
possible up-listing to Schedule 1 (Environment Canada 2005). A Schedule 
3 listing under SARA does not include protection measures, whereas a 
Schedule 1 listing under SARA may include protection measures. We did 
not rely on this potential in our analysis as the action has not yet 
occurred.

Intra-jurisdiction Polar Bear Agreements Within Canada

    Polar bears occur in the Northwest Territories (NWT), Nunavut, 
Yukon Territory, and in the Provinces of Manitoba, Ontario, Quebec, 
Newfoundland, and Labrador (see Figure 1 above). All 13 Canadian polar 
bear populations lie within or are shared with the NWT or Nunavut. The 
NWT and Nunavut geographical boundaries include all Canadian lands and 
marine environment north of the 60th parallel (except the Yukon 
Territory), and all islands and waters in Hudson Bay and Hudson Strait 
up to the low water mark of Manitoba, Ontario, and Quebec. The offshore 
marine areas along the coast of Newfoundland and Labrador are under 
Federal jurisdiction. Although Canada manages each of the 13 
populations of polar bear as separate units, there is a complex sharing 
of responsibilities. While wildlife management has been delegated to 
the Provincial and Territorial Governments, the Federal Government 
(Environment Canada's Canadian Wildlife Service) has an active research 
program and is involved in management of wildlife populations shared 
with other jurisdictions, especially ones with other nations. In the 
NWT, Native Land Claims resulted in Co-management Boards for most of 
Canada's polar bear populations. Canada formed the PBTC and PBAC to 
ensure a coordinated management process consistent with internal and 
international management structures and the International Agreement. 
The committees meet annually to review research and management of polar 
bears in Canada and have representation from all Provincial and 
Territorial jurisdictions with polar bear populations and the Federal 
Government. Beginning in 1984, the Service and biologists from Norway 
and Denmark have, with varying degrees of frequency, participated in 
annual PBTC meetings. The annual meetings of the PBTC provide for 
continuing cooperation between jurisdictions and for recommending 
management actions to the PBAC (Calvert et al. 1995, p. 61).
    The NWT Polar Bear Management Program (GNWT) manages polar bears in 
the Northwest Territories. A 1960 ``Order-in-Council'' granted 
authority to the Commissioner in Council (NWT) to pass ordinances to 
protect polar bears, including the establishment of a quota system. The 
Wildlife Act, 1988, and Big Game Hunting Regulations provide supporting 
legislation which addresses each polar bear population. The Inuvialuit 
and Nunavut Land Claim

[[Page 28286]]

Agreements supersede the Northwest Territories Act (Canada) and the 
Wildlife Act. The Government of Nunavut passed a new Wildlife Act in 
2004 and has management and enforcement authority for polar bears in 
their jurisdiction. Under the umbrella of this authority, polar bears 
are now co-managed through wildlife management boards made up of Land 
Claim Beneficiaries and Territorial and Federal representatives. The 
Boards may develop Local Management Agreements (LMAs) between the 
communities that share a population of polar bears. Management 
agreements are in place for all Nunavut populations. The LMAs are 
signed between the communities, regional wildlife organizations, and 
the Government of Nunavut (Department of Environment) but can be over-
ruled by the Nunavut Wildlife Management Board (NWMB).
    In the case of populations that Nunavut shares with Quebec and 
Ontario, the management agreement is not binding upon residents of 
communities outside of Nunavut jurisdiction. Similarly, in the case of 
populations that Nunavut shares with Manitoba, or Newfoundland and 
Labrador, the management agreement is not binding upon residents of 
communities outside of Nunavut jurisdiction. Regulations implementing 
the LMAs specify who can hunt, season timing and length, age and sex 
classes that can be hunted, and the total allowable harvest for a given 
population. The Department of Environment in Nunavut and the Department 
of Environment and Natural Resources in the NWT have officers to 
enforce the regulations in most communities of the NWT. The officers 
investigate and prosecute incidents of violation of regulations, kills 
in defense of life, or exceeding a quota (USFWS 1997). Canada's inter-
jurisdictional requirements for consultation and development of LMAs 
and oversight through the PBTC and PBAC have resulted in conservation 
benefits for polar bear populations. Although there are some localized 
instances where changes in management agreements may be necessary, 
these arrangements and provisions have operated to minimize the threats 
of overharvest to the species.
    The Service analyzed the overall efficacy of Canada's management of 
polar bears in 1997 (62 FR 7302) and 1999 (64 FR 1529) and determined, 
at those times, that the species was managed by Canada using sound 
scientific principles and in such a manner that existing populations 
would be sustained. We continue to believe that, in general, Canada 
manages polar bears in an effective and sustainable manner. However, as 
discussed above (see ``Harvest Management by Nation''), the Territory 
of Nunavut has recently adopted changes to polar bear management, 
including some increased harvest quotas, that may place a greater 
significance on indigenous knowledge than on scientific data and 
analysis. Management improvements may be desirable for some Canadian 
populations. The Service will continue to monitor polar bear management 
in Canada and actions taken by the Nunavut Government. This is 
particularly important for populations that are currently in decline or 
may decline in the near future.

Russian Federation

    Polar bears are listed in the second issue of the Red Data Book of 
the Russian Federation (2001). The Red Data Book establishes official 
policy for protection and restoration of rare and endangered species in 
Russia. Polar bear populations inhabiting the Barents Sea and part of 
the Kara Sea (Barents-Kara population) are designated as Category IV 
(uncertain status); polar bears in the eastern Kara Sea, Laptev Sea, 
and the western Eastern Siberian Sea (Laptev population) are listed as 
Category III (rare); and polar bears inhabiting the eastern part of the 
Eastern Siberian Sea, Chukchi Sea, and the northern portion of the 
Bering Sea (Chukchi population) are listed as Category V (restoring). 
The main government body responsible for management of species listed 
in the Red Data Book is the Ministry of Natural Resources of the 
Russian Federation. Russia Regional Committees of Natural Resources are 
responsible for managing polar bear populations consistent with Federal 
legislation (Belikov et al. 2002, p. 86).
    Polar bear hunting has been totally prohibited in the Russian 
Arctic since 1956 (Belikov et al. 2002, p. 86). The only permitted take 
of polar bears is catching cubs for public zoos and circuses. There are 
no data on illegal trade of polar bears, and parts and products derived 
from them, although considerable concern persists for unquantified 
levels of illegal harvest that is occurring (Belikov et al. 2002, p. 
87).
    In the Russian Arctic, Natural Protected Areas (NPAs) have been 
established that protect marine and associated terrestrial ecosystems, 
including polar bear habitats. Wrangel and Herald Islands have high 
concentrations of maternity dens and polar bears, and were included in 
the Wrangel Island State Nature Reserve (zapovednik) in 1976. A 1997 
decree by the Russian Federation Government established a 12-nautical 
mile (nm) (22.2 km) marine zone to the Wrangel Island State Nature 
Reserve; the marine zone was extended an additional 24-nm (44.4-km) to 
a total of 36-nm (66.7-km) by a decree from the Governor of Chukotsk 
Autonomous Okruga (Belikov et al. 2002, p. 87). The Franz Josef Land 
State Nature Refuge was established in 1994. In 1996, a federal nature 
reserve (zakaznik) was established on Severnaya Zemlya archipelago. In 
Chukotka, efforts are underway to establish new protected areas where 
polar bears aggregate seasonally; other special protected areas are 
proposed for the Russian High Arctic including the Novosibirsk Islands, 
Severnaya Zemlya, and Novaya Zemlya. However, because they have not yet 
been designated, protections that may be afforded the polar bear under 
these designations have not been considered in our evaluation of the 
adequacy of existing regulatory mechanisms. Within these protected 
areas, conservation and restoration of terrestrial and marine 
ecosystems, and plant and animal species (including the polar bear), 
are the main goals. In 2001, the Nenetskiy State Reserve, which covers 
313,400 ha (774,428 ac), and includes the mouth of the Pechora River 
and adjacent waters of the Barents Sea, was established.
    In May 2001, the Federal law ``Concerning territories of 
traditional use of nature by small indigenous peoples of North, 
Siberia, and Far East of the Russian Federation'' was passed. This law 
established areas for traditional use of nature (TTUN) within NPAs of 
Federal, regional, and local levels to support traditional life styles 
and traditional subsistence use of nature resources for indigenous 
peoples. This law and the law ``Concerning natural protected 
territories'' (1995) regulate protection of plants and animals on the 
TTUNs. The latter also regulates organization, protection and use of 
other types of NPAs: State Nature Reserves (including Biosphere 
Reserves), National Parks, Natural Parks, and State Nature Refuges. 
Special measures on protection of polar bears or other resources may be 
governed by specific regulations of certain NPAs.
    Outside NPAs, protection and use of marine renewable natural 
resources are regulated by Federal legislation; Acts of the President 
of the Russian Federation; regulations of State Duma, Government, and 
Federal Senate of the Russian Federation; and regulations issued by 
appropriate governmental departments. The most important Federal laws 
for nature protection are: ``About environment protection'' (2002), 
``About

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animal world'' (1995), ``About continental shelf of the Russian 
Federation'' (1995), ``About exclusive economical zone of the Russian 
Federation'' (1998), and ``About internal sea waters, territorial sea, 
and adjacent zone of the Russian Federation'' (1998) (Belikov et al. 
2002, p. 87). The effectiveness of laws protecting marine and nearshore 
environments is unknown.

Norway

    According to the Svalbard Treaty of February 9, 1920, Norway 
exercises full and unlimited sovereignty over the Svalbard Archipelago. 
Polar bears have complete protection from harvest under the Svalbard 
Treaty (Derocher et al. 2002b, p. 75), which is effectively 
implemented. The Svalbard Treaty applies to all the islands situated 
between 10 degree and 35 degrees East longitude and between 74 degrees 
and 81 degrees North latitude, and includes the waters up to 4 nm 
offshore. Beyond this zone, Norway claims an economic zone to the 
continental shelf areas to which Norwegian law applies. Under Norwegian 
Game Law, all game, including polar bears, are protected unless 
otherwise stated (Derocher et al. 2002b, p. 75). The main 
responsibility for the administration of Svalbard lies with the 
Norwegian Ministry of Justice. Norwegian civil and penal laws and 
various other regulations are applicable to Svalbard. The Ministry of 
Environment deals with matters concerning the environment and nature 
conservation. The Governor of Svalbard (Sysselmannen), who has 
management responsibilities for freshwater fish and wildlife, pollution 
and oil spill protection, and environmental monitoring, is the cultural 
and environmental protection authority in Svalbard (Derocher et al. 
2002b, p. 75).
    Approximately 65 percent of the land area of Svalbard is totally 
protected, including all major regions of denning by female bears; 
however, protection of habitat is only on land and to 4 nm offshore. 
Marine protection was increased in 2004, when the territorial border of 
the existing protected areas was increased to 12 nm (Aars et al. 2006, 
p. 145). Norway claims control of waters out to 200 nm and regards 
polar bears as protected within this area.
    In 2001, the Norwegian Parliament passed a new Environmental Act 
for Svalbard which went into effect in July 2002. This Act was designed 
to ensure that wildlife, including polar bears, is protected, although 
hunting of some other species is allowed. The only permitted take of 
polar bears is for defense of life. The regulations included specific 
provisions on harvesting, motorized traffic, remote camps and camping, 
mandatory leashing of dogs, environmental pollutants, and environmental 
impact assessments in connection with planning development or 
activities in or near settlements. Some of these regulations were 
specific to the protection of polar bears, e.g., through enforcement of 
temporal and spatial restrictions on motorized traffic and through 
provisions on how and where to camp to ensure adequate bear security 
(Aars et al. 2006, p. 145).
    In 2003, Svalbard designated six new protected areas, two nature 
reserves, three national parks and one ``biotope protection area.'' The 
new protected areas are mostly located around Isfjord, the most 
populated fjord on the west side of the archipelago. Another protected 
area, Hopen, is an important denning area (Aars et al. 2006, p. 145). 
Kong Karls Land is the main denning area and has the highest level of 
protection under the Norwegian land management system. These new 
protected areas cover 4,449 sq km (1,719 sq mi) which is 8 percent of 
the Archipelago's total area (http://www.norway.org/News/archive/2003/200304svalbard.htm), and increase the total area under protection to 65 
percent of the total land area.

Denmark/Greenland

    Under terms of the Greenland Home Rule (1979), the government of 
Greenland is responsible for management of all renewable resources, 
including polar bears. Greenland is also responsible for providing 
scientific data for sound management of polar bear populations and for 
compliance with terms of the 1973 Polar Bear Agreement. Regulations for 
the management and protection of polar bears in Greenland that were 
introduced in 1994 have been amended several times (Jensen 2002, p. 
65). Hunting and reporting regulations include who can hunt polar bears 
(residents who live off the land), protection of family groups with 
cubs of the year, prohibition of trophy hunting, mandatory reporting 
requirements, and regulations on permissible firearms and means of 
transportation (Jensen 2002, p. 65). In addition, there are specific 
regulations that apply to traditional take within the National Park of 
North and East Greenland and the Melville Bay Nature Reserve. A large 
amount of polar bear habitat occurs within the National Park of North 
and East Greenland. One preliminary meeting between Greenland Home Rule 
Government and Canada (with the participation of the government of 
Nunavut) has occurred to discuss management of shared populations. 
Greenland introduced a quota system that took effect on January 1, 2006 
(L[deg]nstrup 2005, p. 133), although no scientifically supportable 
quotas have yet been developed. Some reconsideration to allow a limited 
sport hunt is under discussion within the Greenland governmental 
organizations. We have no information upon which to base a finding that 
Greenland is managing polar bear hunting activities in a manner that 
provides for sustainable populations.

Regulatory Mechanisms to Limit Sea Ice Loss

    Although there are regulatory mechanisms for managing many of the 
threats to polar bears in all countries where the species occurs, as 
well as among range countries through bilateral and multilateral 
agreements, there are no known regulatory mechanisms that are directly 
and effectively addressing reductions in sea ice habitat at this time.
    National and international regulatory mechanisms to comprehensively 
address the causes of climate change are continuing to be developed. 
International efforts to address climate change globally began with the 
United Nations Framework Convention on Climate Change (UNFCCC), adopted 
in May 1992. The stated objective of the UNFCCC is the stabilization of 
GHG concentrations in the atmosphere at a level that would prevent 
dangerous anthropogenic interference with the climate system. The Kyoto 
Protocol, negotiated in 1997, became the first additional agreement 
added to the UNFCCC to set GHG emissions targets. The Kyoto Protocol 
entered into force in February 2005 for signatory countries.
    Domestic U.S. efforts relative to climate change focus on 
implementation of the Clean Air Act, and continued studies programs, 
support for developing new technologies and use of incentives for 
supporting reductions in emissions.
    The recent publication by Canadell et al. (2007) underscores the 
current deficiencies of regulatory mechanisms in addressing root causes 
of climate change. This paper, in the Proceedings of the National 
Academy of Sciences, indicates that the growth rate of atmospheric 
carbon dioxide (CO2), the largest anthropogenic source of 
GHGs, is increasing rapidly. Increasing atmospheric CO2 
concentration is consistent with the results of climate-carbon cycle 
models, but the magnitude of the observed CO2 concentration 
is larger than that estimated by models. The authors suggest that these 
changes ``characterize a carbon cycle that is generating stronger-than-
expected and

[[Page 28288]]

sooner-than-expected climate forcing'' (Canadell et al. 2007).

Conclusion for Factor D

Rationale

    Our review of existing regulatory mechanisms at the national and 
international level has led us to determine that potential threats to 
polar bears from direct take, disturbance by humans, and incidental or 
harassment take are, for the most part, adequately addressed through 
international agreements, national, State, Provincial or Territorial 
legislation, and other regulatory mechanisms.
    As described under Factor A, the primary threat to the survival of 
the polar bear is loss of sea ice habitat and its consequences to polar 
bear populations. Our review of existing regulatory mechanisms has led 
us to determine that, although there are some existing regulatory 
mechanisms to address anthropogenic causes of climate change, there are 
no known regulatory mechanisms in place at the national or 
international level that directly and effectively address the primary 
threat to polar bears-the rangewide loss of sea ice habitat.

Determination for Factor D

    After evaluating the best available scientific information, we have 
determined that existing regulatory mechanisms at the national and 
international level are adequate to address actual and potential 
threats to polar bears from direct take, disturbance by humans, and 
incidental or harassment take.
    We note that GHG loading in the atmosphere can have a considerable 
lag effect on climate, so that what has already been emitted will have 
impacts out to 2050 and beyond (IPCC 2007, p. 749; J. Overland, NOAA, 
in litt. to the Service, 2007)). This is reflected in the similarity of 
low, medium, and high SRES emissions scenarios out to about 2050 (see 
Figure 5). As noted above, the publication of Canadell et al. (2007) 
underscores the current deficiencies of regulatory mechanisms in 
addressing root causes of climate change. This paper indicates that the 
growth rate of atmospheric carbon dioxide (CO2), the largest 
anthropogenic source of GHGs, is increasing rapidly. Increasing 
atmospheric CO2 concentration is consistent with the results 
of climate-carbon cycle models, but the magnitude of the observed 
CO2 concentration is larger than that estimated by models 
(Canadell et al. 2007). We have determined that there are no known 
regulatory mechanisms in place at the national or international level 
that directly and effectively address the primary threat to polar 
bears-the rangewide loss of sea ice habitat within the foreseeable 
future. We also acknowledge that there are some existing regulatory 
mechanisms to address anthropogenic causes of climate change, and these 
mechanisms are not expected to be effective in counteracting the 
worldwide growth of GHG emissions within the foreseeable future.

Factor E. Other Natural or Manmade Factors Affecting the Polar Bear's 
Continued Existence

Contaminants

    Understanding the potential effects of contaminants on polar bears 
in the Arctic is confounded by the wide range of contaminants present, 
each with different chemical properties and biological effects, and the 
differing geographic, temporal, and ecological exposure regimes 
impacting each of the 19 polar bear populations. Further, contaminant 
concentrations in polar bear tissues differ with polar bears' age, sex, 
reproductive status, and other factors. Contaminant sources and 
transport; geographical, temporal patterns and trends; and biological 
effects are detailed in several recent Arctic Monitoring and Assessment 
Program (AMAP) publications (AMAP 1998; AMAP 2004a; AMAP 2004b; AMAP 
2005). Three main groups of contaminants in the Arctic are thought to 
present the greatest potential threat to polar bears and other marine 
mammals: petroleum hydrocarbons, persistent organic pollutants (POPS), 
and heavy metals.

Petroleum Hydrocarbons

    The principal petroleum hydrocarbons in the Arctic include crude 
oil, refined oil products, polynuclear aromatic hydrocarbons, and 
natural gas and condensates (AMAP 1998, p. 661). Petroleum hydrocarbons 
come from both natural and anthropogenic sources. The primary natural 
source is oil seeps. AMAP (2007, p. 18) notes that ``natural seeps are 
the major source of petroleum hydrocarbon contamination in the Arctic 
environment.'' Anthropogenic sources include activities associated with 
exploration, development, and production of oil (well blowouts, 
operational discharges), ship- and land-based transportation of oil 
(oil spills from pipelines, accidents, leaks, and ballast washings), 
discharges from refineries and municipal waste water, and combustion of 
wood and fossil fuels. In addition to direct contamination, petroleum 
hydrocarbons are transported from more southerly areas to the Arctic 
via long range atmospheric and oceanic transport, as well as by north-
flowing rivers (AMAP 1998, p. 671).
    Polar bears are particularly vulnerable to oil spills due to their 
inability to effectively thermoregulate when their fur is oiled, and to 
poisoning that may occur from ingestion of oil while from grooming or 
eating contaminated prey (St. Aubin 1990, p. 237). In addition, polar 
bears are curious and are likely to investigate oil spills and oil-
contaminated wildlife. Under some circumstances polar bears are 
attracted to offshore drilling platforms (Stirling 1988, p. 6; Stirling 
1990, p. 230). Whether healthy polar bears in their natural environment 
would avoid oil spills and contaminated seals is unknown; hungry polar 
bears are likely to scavenge contaminated seals, as they have shown no 
aversion to eating and ingesting oil (St. Aubin 1990, p. 237; Derocher 
and Stirling 1991, p. 56). Polar bears are generally known to be 
attracted to various refined hydrocarbon products such as anti-freeze, 
hydraulic fluids, etc., and may consume them, which in some instances 
has resulted in death (Amstrup et al. 1989).
    The most direct exposure of polar bears to petroleum hydrocarbons 
would come from direct contact with and ingestion of oil from acute and 
chronic oil spills. Polar bears' range overlaps with many active and 
planned oil and gas operations within 40 km (25 mi) of the coast or 
offshore. In the past, no large volume major oil spills of more than 
3,000 barrels have occurred in the marine environment within the range 
of polar bears. Oil spills associated with terrestrial pipelines have 
occurred in the vicinity of polar bear habitat, including denning areas 
(e.g., Russian Federation, Komi Republic, 1994 oil spill, http://www.american.edu/ted/KOMI.HTM). Despite numerous safeguards to prevent 
spills, smaller spills do occur. An average of 70 oil and 234 waste 
product spills per year occurred between 1977 and 1999 in the North 
Slope oil fields (71 FR 14456). Many spills are small (less than 50 
barrels) by oil and gas industry standards, but larger spills (greater 
than or equal to 500 barrels) account for much of the annual volume. 
The largest oil spill to date on the North Slope oil fields in Alaska 
(estimated volume of approximately 4,786 barrels) occurred on land in 
March 2006, and resulted from an undetected leak in a corroded pipeline 
(see State of Alaska Prevention and Emergency Response web site (http:/
/www.dec.state.ak.us/spar/perp/

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response/sum--fy06/060302301/060302301--index.htm).
    The MMS (2004, pp. 10, 127) estimated an 11 percent chance of a 
marine spill greater than 1,000 barrels in the Beaufort Sea from the 
Beaufort Sea Multiple Lease Sale in Alaska. The Minerals Management 
Service (MMS) prepared an EIS on the Chukchi Sea Planning Area; Oil and 
Gas Lease Sale 193 and Seismic Surveying Activities in the Chukchi Sea; 
they determined that polar bears could be affected by both routine 
activities and a large oil spill (MMS 2007, pp. ES 1-10). Regarding 
routine activities, the EIS determined that small numbers of polar 
bears could be affected by ``noise and other disturbance caused by 
exploration, development, and production activities'' (MMS 2007, p. ES-
4). In addition, the EIS evaluated events that would be possible over 
the life of the hypothetical development and production that could 
follow the lease sale, and estimated that ``the chance of a large spill 
greater than or equal to 1,000 barrels occurring and entering offshore 
waters is within a range of 33 to 51 percent.'' If a large spill were 
to occur, the analysis conducted as part of the EIS process identified 
potentially significant impacts to polar bears occurring in the area 
affected by the spill; the evaluation was done without regard to the 
effect of mitigating measures (MMS 2007, p. ES-4).
    Oil spills in the fall or spring during the formation or break-up 
of sea ice present a greater risk because of difficulties associated 
with clean up during these periods, and the presence of bears in the 
prime feeding areas over the continental shelf. Amstrup et al. (2000a, 
p. 5) concluded that the release of oil trapped under the ice from an 
underwater spill during the winter could be catastrophic during spring 
break-up if bears were present. During the autumn freeze-up and spring 
break-up periods, any oil spilled in the marine environment would 
likely concentrate and accumulate in open leads and polynyas, areas of 
high activity for both polar bears and seals (Neff 1990, p. 23). This 
would result in an oiling of both polar bears and seals (Neff 1990, pp. 
23-24; Amstrup et al. 2000a, p. 3; Amstrup et al. 2006a, p. 9).
    The MMS operating regulations require that Outer Continental Shelf 
(OCS) activities are carried out in a safe and environmentally sound 
manner to prevent harm, damage or waste of, any natural resources any 
life (including marine mammals such as the polar bear), property, or 
the marine, coastal, or human environment. Regulations for exploration, 
development, and production operations on the OCS are specified in 30 
CFR part 250. These regulations provide measures for pollution 
prevention and control, including drilling procedures specific to 
individual wells, redundant safety and pollution prevention equipment, 
blowout preventers and subsurface safety valves, training of the 
drilling crews, and structural and safety system review of production 
facilities. Regulations related to oil-spill prevention and response 
are specified in 30 CFR part 254.
    As previously discussed in the ``Oil and Gas Exploration, 
Development, and Production'' section, the actual history of oil and 
gas activities in the Beaufort and Chukchi Seas demonstrate that 
operations have been done safely and with a negligible effect on 
wildlife and the environment. On the Beaufort and Chukchi OCS, 35 
exploratory wells have been drilled. During this drilling period, 
approximately 26.7 barrels of petroleum product have been spilled, and, 
of those 26.7 barrels, approximately 24 barrels were recovered or 
cleaned up. MMS and industry standards require strict protection 
measures during production of energy resources. For example, although 
it is located in State of Alaska waters, the shared State/Federal 
Northstar production facility used a specially-fabricated pipe that was 
buried 7-11 ft below the sea floor to prevent damage from ice keels, is 
pigged (the practice of using pipeline inspection gauges or 'pigs' to 
perform various operations on a pipeline without stopping the flow of 
the product in the pipeline), and has several different monitoring 
systems to detect spills.
    In addition, NOAA and the Service require monitoring and avoidance 
measures for marine mammals during critical times during exploration 
and production. The Marine Mammal Observers (MMO) are required by NOAA 
and the Service to be on deck watching for animals. Depending on the 
activity and the particular circumstances, operations may be 
temporarily halted or modified. In some circumstances, hazing may be 
used to keep the polar bears away from operations. There are specific 
guidelines the MMO follow for observing and hazing. Hazing is only used 
to protect the safety of humans or the marine mammal.
    Prior to any exploration, development, or production activities, 
companies must submit an Exploration Plan or a Development/Production 
Plan to MMS for review and approval. In Alaska, MMS provides a copy of 
all such plans to the Service for review. Prior to conducting drilling 
operations, the operator must also obtain approval for an Application 
for Permit to Drill (APD). The APD requires detailed information on the 
seafloor and shallow seafloor conditions for the drill site from 
shallow geophysical and, if necessary, archaeological and biological 
surveys. The APD requires detailed information about the drilling 
program to allow evaluation of operational safety and pollution-
prevention measures. The lessee must use the best available and safest 
technology to minimize the potential for uncontrolled well flow, 
through the use of blowout preventers. For example, the operator also 
must identify procedures to curtail operations during critical ice or 
weather conditions.
    In addition, the MMS identifies additional protection measures for 
the polar bear through the use of Information to Lessees (ITL). Lessees 
are advised that incidental take of marine mammals is prohibited unless 
authorization is received under the MMPA. For example, for Sale 193 in 
the Chukchi Sea, potential lessees were advised to obtain MMPA 
authorizations from FWS and to consult with the Service, local Native 
communities and the Alaska Nanuuq Commission during exploration, 
production and spill response planning, to assure adequate protection 
for the polar bear. Lessees are specifically advised to conduct their 
activities in a way that will limit potential encounters and 
interaction between lease operations and polar bears.
    For production, the lessee must design, fabricate, install, use, 
inspect, and maintain all platforms and structures on the OCS to ensure 
their structural integrity for the safe conduct of operations at 
specific locations. All tubing installations open to hydrocarbon-
bearing zones below the surface must be equipped with safety devices 
that will shut off the flow from the well in the event of an emergency, 
unless the well is incapable of flowing. All surface production 
facilities must be designed, installed, and maintained in a manner that 
provides for efficiency, safety of operations, and protection of the 
environment, including marine mammals.
    Pipeline-permit applications to MMS include the pipeline location 
drawing, profile drawing, safety schematic drawing, pipe-design data to 
scale, a shallow-hazard-survey report, and an archaeological report. 
The MMS evaluates the design and fabrication of the pipeline. No 
pipeline route will be approved by MMS if any bottom-disturbing 
activities (from the pipeline

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itself or from the anchors of lay barges and support vessels) encroach 
on any biologically sensitive areas. The operators are required to 
monitor and inspect pipelines by methods prescribed by MMS for any 
indication of pipeline leakage.
    MMS conducts onsite inspections to ensure compliance with plans and 
with the MMS pollution prevention regulations. It has been practice in 
Alaska to have an MMS inspector onboard drilling vessels during key 
drilling procedures.
    In compliance with 30 CFR part 254, all owners and operators of 
oil-handling, oil-storage, or oil-transportation facilities located 
seaward of the coastline must submit an Oil Spill Response Plan to MMS 
for approval. Owners or operators of offshore pipelines are required to 
submit a plan for any pipeline that carries oil, condensate that has 
been injected into the pipeline, or gas and naturally occurring 
condensate.
    Increases in circumpolar Arctic oil and gas development, coupled 
with increases in shipping and/or development of offshore and land-
based pipelines, increase the potential for an oil spill to negatively 
affect polar bears and/or their habitat. Future declines in the Arctic 
sea ice may result in increased tanker traffic in high bear use areas 
(Frantzen and Bambulyak 2003, p. 4), which would increase the chances 
of an oil spill from a tanker accident, ballast discharge, or 
discharges during the loading and unloading of oil at the ports. 
Amstrup et al. (2007, p. 31) assumed that human activities related to 
oil and gas exploration and development are likely to increase with 
disappearance of sea ice from many northern areas. At the same time, 
less sea ice will facilitate an increase in offshore developments. More 
offshore development will increase the probability of hydrocarbon 
discharges into polar bear habitat (Stirling 1990, p. 228). The record 
of over 30 years of predominantly terrestrial oil and gas development 
in Alaska suggests that with proper management, potential negative 
effects of these activities on polar bears can be minimized (Amstrup 
1993, p. 250; Amstrup 2000, pp. 150-154; Amstrup 2003, pp. 597, 604; 
Amstrup et al. 2004, p. 23) (for details see the ``Oil and Gas 
Exploration, Development, and Production'' section of this final rule). 
Increased industrial activities in the marine environment will require 
additional monitoring.
    Amstrup et al. (2006) evaluated the potential effects of a 
hypothetical 5,912-barrel oil spill (the largest spill thought possible 
from a pipeline spill) on polar bears from the Northstar offshore oil 
production facility in the southern Beaufort Sea, and found that there 
is a low probability that a large number of bears (e.g., 25-60) might 
be affected by such a spill. For the purposes of this scenario, it was 
assumed that a polar bear would die if it came in contact with the oil. 
Amstrup et al. (2006a, p.21) found that 0-27 bears could potentially be 
oiled during the open water conditions in September, and from 0-74 
bears in mixed ice conditions during October. If such a spill occurred, 
particularly during the broken ice period, the impact of the spill 
could be significant to the Southern Beaufort Sea polar bear population 
(Amstrup et al. 2006a, pp. 7, 22; 65 FR 16833). The sustainable harvest 
yield per year for the Southern Beaufort Sea population, based on a 
stable population size of 1,800 bears, was estimated to be 81.1 bears 
(1999-2000 to 2003-2004) (Lunn et al. 2005, p. 107). For the same time 
period, the average harvest was 58.2 bears, leaving an additional 
buffer of 23 bears that could have been removed from the population. 
Therefore, an oil spill that resulted in the death of greater than 23 
bears, which was possible based on the range of oil spill-related 
mortalities from the previous analysis, could have had population level 
effects for polar bears in the southern Beaufort Sea. However, the 
harvest figure of 81 bears may no longer be sustainable for the 
Southern Beaufort Sea population, so, given the average harvest rate 
cited above, fewer than 23 oil spill-related mortalities could result 
in population-level effects.
    The number of polar bears affected by an oil spill could be 
substantially higher if the spill spread to areas of seasonal polar 
bear concentrations, such as the area near Kaktovik, Alaska, in the 
fall, and could have a significant impact to the Southern Beaufort Sea 
polar bear population. It seems likely that an oil spill would affect 
ringed seals the same way the Exxon Valdez oil spill affected harbor 
seals (Frost et al. 1994a, pp. 108-110; Frost et al. 1994b, pp. 333-
334, 343-344, 346-347; Lowry et al. 1994, pp. 221-222; Spraker et al. 
1994, pp. 300-305). As with polar bears, the number of animals killed 
would vary depending upon the season and spill size (NRC 2003, pp. 168-
169). Oil spills remain a concern for polar bears throughout their 
range. Increased industrial activities in the marine environment will 
require additional monitoring. Oil and gas exploration, development, 
and production effects on polar bears and their habitat are discussed 
under Factor A.

Persistent Organic Pollutants (POPs)

    Contamination of the Arctic and sub-Arctic regions through long-
range transport of persistent organic pollutants has been recognized 
for over 30 years (Bowes and Jonkel 1975, p. 2,111; de March et al. 
1998, p. 184; Proshutinsky and Johnson 2001, p. 68; MacDonald et al. 
2003, p. 38). These compounds are transported via large rivers, air, 
and ocean currents from the major industrial and agricultural centers 
located at more southerly latitudes (Barrie et al. 1992; Li et al. 
1998, pp. 39-40; Proshutinsky and Johnson 2001, p. 68; Lie et al. 2003, 
p. 160). The presence and persistence of these contaminants within the 
Arctic is dependent on many factors, including transport routes, 
distance from source, and the quantity and chemical composition of the 
releases. Climate change may increase long-range marine and atmospheric 
transport of contaminants (Macdonald et al. 2003, p. 5; Macdonald et al 
2005, p.15). For example, increased rainfall in northern regions has 
increased river discharges into the Arctic marine environment. Many 
north-flowing rivers originate in heavily industrialized regions and 
carry heavy contaminant burdens (Macdonald et al. 2005, p. 31).
    The Arctic ecosystem is particularly sensitive to environmental 
contamination due to the slower rate of breakdown of persistent organic 
pollutants, including organochlorine (OC) compounds, the relatively 
simple food chains, and the presence of long-lived organisms with low 
rates of reproduction and high lipid levels. The persistence and 
tendency of OCs to reside and concentrate in fat tissues of organisms 
increases the potential for bioaccumulation and biomagnification at 
higher trophic levels (Fisk et al. 2001, pp. 225-226). Polar bears, 
because of their position at the top of the Arctic marine food chain, 
have some of the highest concentrations of OCs of any Arctic mammals 
(Braune et al. 2005, p. 23). Considering the potential for increases in 
both local and long-range transport of contaminants to the Arctic, with 
warmer climate and less sea ice, the influence these activities have on 
polar bears is likely to increase.
    The most studied POPs in polar bears include polychlorinated 
biphenyls (PCBs), chlordanes (CHL), DDT and its metabolites, toxaphene, 
dieldrin, hexachloroabenzene (HCB), hexachlorocyclohexanes (HCHs), and 
chlorobenzenes (ClBz). Overall, the relative proportion of the more 
recalcitrant compounds, such as PCB 153 and [beta]-HCH, appears to be 
increasing in polar bears (Braune et al. 2005, p. 50).

[[Page 28291]]

Although temporal trend information is lacking, newer compounds, such 
as polybrominated diphenyl ethers (PBDEs), polychlorinated naphthalenes 
(PCNs), perflouro-octane sulfonate (PFOsS), perfluoroalkyl acids 
(PFAs), and perflourocarboxylic acids (PFCAs), have been recently found 
in polar bears (Braune et al. 2005, p. 5). Of this relatively new suite 
of compounds, there is concern that both PFOsS, which are increasing 
rapidly, and PBDEs are a potential risk to polar bears (Ikonomou et al. 
2002, p. 1,886; deWit 2002, p. 583; Martin et al. 2004, p. 373; Braune 
et al. 2005, p. 25; Smithwick et al. 2006, p. 1,139).
    Currently, polychlorinated dibenzo-p-dioxins (PCDDs), dibenzofurans 
(PCDFs) and dioxin-like PCBs are at relatively low concentrations in 
polar bears (Norstrom et al. 1990, p. 14). The highest PCB 
concentrations have been found in polar bears from the Russian Arctic 
(Franz Joseph Land and the Kara Sea), with decreasing concentrations to 
the east and west (Andersen et al. 2001, p. 231). Overall, there is 
evidence of declines in PCBs for most polar bear populations. The 
pattern of distribution for most other chlorinated hydrocarbons and 
metabolites generally follows that of PCBs, with the highest 
concentrations of DDT-related compounds and CHLs in Franz Joseph Land 
and the Kara Sea, followed by East Greenland, Svalbard, the eastern 
Canadian Arctic populations, the western Canadian populations, the 
Siberian Sea, and finally the lowest concentrations in Alaska 
populations (Bernhoft et al. 1997; Norstrom et al. 1998, p. 361; 
Andersen et al. 2001, p. 231; Kucklick et al. 2002, p. 9; Lie et al. 
2003, p. 159; Verreault et al. 2005, pp. 369-370; Braune et al. 2005, 
p. 23).
    The polybrominated diphenyl ethers (PBDEs) share similar physical 
and chemical properties with PCBs (Wania and Dugani 2003, p. 1,252; 
Muir et al. 2006, p. 449), and are thought to be transported to the 
Arctic by similar pathways. Muir et al. (2006, p. 450) analyzed 
archived samples from Dietz et al. (2004) and Verreault et al. (2005) 
for PBDE concentrations, finding the highest mean PBDE concentrations 
in female polar bear adipose tissue from East Greenland and Svalbard. 
Lower concentrations of PBDEs were found in adipose tissue from the 
Canadian and Alaskan populations (Muir et al. 2006, p. 449). 
Differences between the PBDE concentrations and composition in liver 
tissue between the Southern Beaufort Sea and the Chukchi Seas 
populations in Alaska suggest differences in the sources of PBDEs 
exposure (Kannan et al. 2005, p. 9057). Overall, the sum of the PBDE 
concentrations are much lower and less of a concern compared to PCBs, 
oxychlordane, and some of the more recently discovered perflouorinated 
compounds. PBDEs are metabolized to a high degree in polar bears and 
thus do not bioaccumulate as much as PCBs (Wolkers et al. 2004, p. 
1,674).
    Although baseline information on contaminant concentrations is 
available, determining the biological effects of these contaminants in 
polar bears is difficult. Field observations of reproductive impairment 
in females and males, lower survival of cubs, and increased mortality 
of females in Svalbard, Norway, however, suggest that high 
concentrations of PCBs may have contributed to population level effects 
in the past (Wiig 1998, p. 28; Wiig et al. 1998, p. 795; Skaare et al. 
2000, p. 107; Haave et al. 2003, pp. 431, 435; Oskam et al. 2003, p. 
2134; Derocher et al. 2003, p. 163). At present, however, PCB 
concentrations are not thought to be resulting population level effects 
on polar bears. Organochlorines may adversely affect the endocrine 
system as metabolites of these compounds are toxic and some have 
demonstrated endocrine disrupting activity (Letcher et al. 2000; Braune 
et al. 2005, p. 23). High concentrations of organochlorines may also 
affect the immune system, resulting in a decreased ability to produce 
antibodies (Lie et al. 2004, pp. 555-556).
    Despite the regulatory steps taken to decrease the production or 
emissions of toxic chemicals, increases in some relatively new 
compounds are cause for concern. Some of these compounds have increased 
in the last decade (Ikonomou et al. 2002, p. 1,886; Muir et al. 2006, 
p. 453).

Metals

    Numerous essential and non-essential elements have been reported on 
for polar bears and the most toxic or abundant elements in marine 
mammals are mercury, cadmium, selenium, and lead. Of these, mercury is 
of greatest concern because of its potential toxicity at relatively low 
concentrations, and its ability to biomagnify and bioaccumulate in the 
food web. Polar bears from the western Canadian Arctic and southwest 
Melville Island, Canada (Braune et al. 1991, p. 263; Norstrom et al. 
1986, p. 195; AMAP 2005, pp. 42, 62, 134), and ringed seals from the 
western Canadian Arctic (Wagemann et al. 1996, p. 41; Deitz et al. 
1998, p. 433; Dehn et al. 2005, p. 731; Riget et al. 2005, p. 312), 
have some of the highest known mercury concentrations. Wagemann et al. 
(1996, pp. 51, 60) observed an increase in mercury from eastern to 
western Canadian ringed seal populations and attributed this pattern to 
a geologic gradient in natural mercury deposits.
    Although the contaminant concentrations of mercury found in marine 
mammals often exceed those found to cause effects in terrestrial 
mammals (Fisk et al. 2003, p. 107), most marine mammals appear to have 
evolved effective biochemical mechanisms to tolerate high 
concentrations of mercury (AMAP 2005, p.123). Polar bears are able to 
break down methylmercury and accumulate higher levels than their 
terrestrial counterparts without detrimental effects (AMAP 2005, p. 
123). Evidence of mercury poisoning is rare in marine mammals, but 
Dietz et al. (1990, p. 49) noted that sick marine mammals often have 
higher concentrations of methylmercury, suggesting that these animals 
may no longer be able to detoxify methylmercury. Hepatic mercury 
concentrations are well below those expected to cause biological 
effects in most polar bear populations (AMAP 2005, p. 118). Only two 
polar bear populations have concentrations of mercury close to the 
biological threshold levels of 60 micrograms wet weight reported for 
marine mammals (AMAP 2005, p. 121): the Viscount Melville population 
(southwest Melville Sound), Canada, and the Southern Beaufort Sea 
population (eastern Beaufort Sea) (Dietz et al. 1998, p. 435, Figure 7-
52).

Shipping and Transportation

    Observations over the past 50 years show a decline in Arctic sea 
ice extent in all seasons, with the most prominent retreat in the 
summer. Climate models project an acceleration of this trend with 
periods of extensive melting in spring and autumn, thus opening new 
shipping routes and extending the period that shipping is practical 
(ACIA 2005, p. 1,002). Notably, the navigation season for the Northern 
Sea Route (across northern Eurasia) is projected to increase from 20-30 
days per year to 90-100 days per year. Russian scientists cite 
increasing use of a Northern Sea Route for transit and regional 
development as a major source of disturbance to polar bears in the 
Russian Arctic (Wiig et al. 1996, pp. 23-24; Belikov and Boltunov 1998, 
p. 113; Ovsyanikov 2005, p. 171). Commercial navigation on the Northern 
Sea Route could disturb polar bear feeding and other behaviors, and 
would increase the risk of oil spills (Belikov et al. 2002, p. 87).
    Increased shipping activity may disturb polar bears in the marine

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environment, adding additional energetic stresses. If ice-breaking 
activities occur, they may alter habitats used by polar bears, possibly 
creating ephemeral lead systems and concentrating ringed seals within 
the refreezing leads. This, in turn, may allow for easier access to 
ringed seals and may have some beneficial values. Conversely, this may 
cause polar bears to use areas that may have a higher likelihood of 
human encounters as well as increased likelihood of exposure to oil, 
waste products, or food wastes that are intentionally or accidentally 
released into the marine environment. If shipping involved the tanker 
transport of crude oil or oil products, there would be some increased 
likelihood of small to large volume spills and corresponding oiling of 
polar bears, as well as potential effects on seal prey species (AMAP 
2005, pp. 91, 127).
    The PBSG (Aars et al. 2006, pp. 22, 58, 171) recognized the 
potential for increased shipping and marine transportation in the 
Arctic with declining seasonal sea ice conditions. The PBSG recommended 
that the parties to the 1973 Polar Bear Agreement take appropriate 
measures to monitor, regulate, and mitigate ship traffic impacts on 
polar bear populations and habitats (Aars et al. 2006, p. 58).

Ecotourism

    Properly regulated ecotourism will likely not have a negative 
effect on polar bear populations, although increasing levels of 
ecotourism and photography in polar bear viewing areas and natural 
habitats may lead to increased polar bear-human conflicts. Ecotourists 
and photographers may inadvertently displace bears from preferred 
habitats or alter natural behaviors (Lentfer 1990, p.19; Dyck and 
Baydack 2004, p. 344). Polar bears are inquisitive animals and often 
investigate novel odors or sights. This trait can lead to polar bears 
being killed at cabins and remote stations where they investigate food 
smells (Herrero and Herrero 1997, p. 11). Conversely, ecotourism has 
the effect of increasing the worldwide constituency of people with an 
interest in polar bears and their conservation.

Conclusion for Factor E

Rationale

    Contaminant concentrations are not presently thought to have 
population level effects on most polar bear populations. However, 
increased exposure to contaminants has the potential to operate in 
concert with other factors, such nutritional stress from loss or 
degradation of the sea ice habitat or decreased prey availability and 
accessibility, to lower recruitment and survival rates that ultimately 
would have negative population level effects. Despite the regulatory 
steps taken to decrease the production or emissions of toxic chemicals, 
use of some relatively new compounds has increased recently in the last 
decade (Ikonomou et al. 2002, p. 1,886; Muir et al. 2006, p. 453). 
Several populations, such as the Svalbard, East Greenland, and Kara Sea 
populations, that currently have some of the highest contaminant 
concentrations may be affected, but we do not believe these effects 
will be significant within the foreseeable future. Increasing levels of 
ecotourism and shipping may lead to greater impacts on polar bears. The 
potential extent of impact is related to changing sea ice conditions 
and resulting changes to polar bear distribution.

Determination for Factor E

    We have evaluated the best available scientific information on 
other natural or manmade factors that are affecting polar bears, and 
have determined that contaminants, ecotourism, and shipping do not 
threaten the polar bear throughout all or any significant portion of 
its range. Some of these, particularly contaminants and shipping, may 
become more significant threats in the future for polar bear 
populations experiencing declines related to nutritional stress brought 
on by sea ice and environmental changes.

Finding

    We have carefully considered all available scientific and 
commercial information past, present, and future threats faced by the 
polar bear. We reviewed the petition, information available in our 
files, scientific journals and reports, and other published and 
unpublished information submitted to us during the public comment 
periods following our February 9, 2006 (71 FR 6745) 90-day petition 
finding, the January 9, 2007 (72 FR 1064), 12-month Finding and 
proposed rule, and during public hearings held in Washington, DC and 
Alaska. In addition, at the request of the Secretary of the Interior, 
the USGS analyzed and integrated a series of studies on polar bear 
population dynamics, range-wide habitat use and changing sea ice 
conditions in the Arctic, and provided the Service with nine scientific 
reports on the results of their studies. We carefully evaluated these 
new reports and other published and unpublished information submitted 
to us following the public comment period on these reports, initially 
opened for 15 days (September 20, 2007; 72 FR 53749), but then extended 
until October 22, 2007 (72 FR 56979).
    In accordance with our policy published on July 1, 1994 (59 FR 
34270), we solicited and received expert opinions on both the Range 
Wide Status Review of the Polar Bear (Ursus maritimus) (Schliebe et al. 
2006a), and subsequently on the 12-month finding and proposed rule (72 
FR 1064). We received reviews of the draft Status Review from 10 
independent experts and on the proposed rule from 14 independent 
experts in the fields of polar bear ecology, contaminants and 
physiology, climatic science and physics, Arctic ecology, pinniped 
(seal) ecology, and traditional ecological knowledge (TEK). We also 
consulted with recognized polar bear experts and other Federal, State, 
and range country resource agencies.
    In making this finding, we recognize that polar bears evolved in 
the ice-covered waters of the circumpolar Arctic, and are reliant on 
sea ice as a platform to hunt and feed on ice-seals, to seek mates and 
breed, to move to feeding sites and terrestrial maternity denning 
areas, and for long-distance movements. The rapid retreat of sea ice in 
the summer and overall diminishing sea ice throughout the year in the 
Arctic is unequivocal and extensively documented in scientific 
literature. Further extensive recession of sea ice is projected by the 
majority of state-of-the-art climate models, with a seasonally ice-free 
Arctic projected by the middle of the 21st century by many of those 
models. Sea ice habitat will be subjected to increased temperatures, 
earlier melt periods, increased rain-on-snow events, and shifts in 
atmospheric and marine circulation patterns.
    Under Factor A (``Present or Threatened Destruction, Modification, 
or Curtailment of its habitat or range''), we have determined that 
ongoing and projected loss of the polar bear's crucial sea ice habitat 
threatens the species throughout all of its range. Productivity, 
abundance, and availability of ice seals, the polar bear's primary prey 
base, would be diminished by the projected loss of sea ice, and 
energetic requirements of polar bears for movement and obtaining food 
would increase. Access to traditional denning areas would be affected. 
In turn, these factors would cause declines in the condition of polar 
bears from nutritional stress and reduced productivity. As already 
evidenced in the Western Hudson Bay and Southern Beaufort Sea 
populations, polar bears would experience reductions in survival and 
recruitment rates. The eventual effect is that polar bear populations 
would

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decline. The rate and magnitude of decline would vary among 
populations, based on differences in the rate, timing, and magnitude of 
impacts. However, within the foreseeable future, all populations would 
be affected, and the species is likely to become in danger of 
extinction throughout all of its range due to declining sea ice 
habitat.
    Under Factor B (``Overutilization for Commercial, Recreational, 
Scientific, or Educational Purposes'') we note that polar bears are 
harvested in Canada, Alaska, Greenland, and Russia, and we acknowledge 
that harvest is the consumptive use of greatest importance and 
potential effect to polar bear. Further we acknowledge that forms of 
removal other than harvest (such as defense-of-life take) have been 
considered in this analysis. While overharvest occurs for some 
populations, laws and regulations for most management programs have 
been instituted to provide sustainable harvests over the long term. As 
the status of populations declines, it may be necessary for management 
entitites to implement harvest reductions in order to limit the 
potential effect of harvest. This capability has a proven track record 
in Canada, and is adaptive to future needs. Further, bilateral 
agreements or conservation agreements have been developed to address 
issues of overharvest. Conservation benefits from agreements that are 
in development or have not yet been implemented are not considered in 
our evaluation. We also acknowledge that increased levels of bear-human 
encounters are expected in the future and that encounters may result in 
increased mortality to bears at some unknown level. Adaptive management 
programs, such as implementing polar bear patrols, hazing programs, and 
efforts to minimize attraction of bears to communities, to address 
future bear-human interaction issues, including on-the-land ecotourism 
activities, are anticipated.
    Harvest is likely exacerbating the effects of habitat loss in 
several populations. In addition, continued harvest and increased 
mortality from bear-human encounters or other forms of mortality may 
become a more significant threat factor in the future, particularly for 
populations experiencing nutritional stress or declining population 
numbers as a consequence of habitat change. Although harvest, increased 
bear-human interaction levels, defense-of-life take, illegal take, and 
take associated with scientific research live-capture programs are 
occurring for several populations, we have determined that 
overutilization does not currently threaten the species throughout all 
or a significant portion of its range.
    Under Factor C (``Disease and Predation'') we acknowledge that 
disease pathogens are present in polar bears; no epizootic outbreaks 
have been detected; and intra-specific stress through cannibalism may 
be increasing; however, population level effects have not been 
documented. Potential for disease outbreaks, an increased possibility 
of pathogen exposure from changed diet or the occurrence of new 
pathogens that have moved northward with a warming environment, and 
increased mortality from intraspecific predation (cannibalism) may 
become more significant threat factors in the future for polar bear 
populations experiencing nutritional stress or declining population 
numbers. We have determined that disease and predation (including 
intraspecific predation) do not threaten the species throughout all or 
a significant portion of its range.
    Under Factor D (``Inadequacy of Existing Regulatory Mechanisms''), 
we have determined that existing regulatory mechanisms at the national 
and international level are generally adequate to address actual and 
potential threats to polar bears from direct take, disturbance by 
humans, and incidental or harassment take. We have determined that 
there are no known regulatory mechanisms in place at the national or 
international level that directly and effectively address the primary 
threat to polar bears--the rangewide loss of sea ice habitat within the 
foreseeable future.
    We acknowledge that there are some existing regulatory mechanisms 
to address anthropogenic causes of climate change, and these mechanisms 
are not expected to be effective in counteracting the worldwide growth 
of GHG emissions in the foreseeable future.
    Under Factor E (``Other Natural or Manmade Factors Affecting the 
Polar Bear's Continued Existence'') we reviewed contaminant 
concentrations and find that, in most populations, contaminants have 
not been found to have population level effects. We further evaluated 
increasing levels of ecotourism and shipping that may lead to greater 
impacts on polar bears. The extent of potential impact is related to 
changing ice conditions, polar bear distribution changes, and relative 
risk for a higher interaction between polar bears and ecotourism or 
shipping. Certain factors, particularly contaminants and shipping, may 
become more significant threats in the future for polar bear 
populations experiencing declines related to nutritional stress brought 
on by sea ice and environmental changes. We have determined, however, 
that contaminants, ecotourism, and shipping do not threaten the polar 
bear throughout all or a significant portion of its range.
    On the basis of our thorough evaluation of the best available 
scientific and commercial information regarding present and future 
threats to the polar bear posed by the five listing factors under the 
Act, we have determined that the polar bear is threatened throughout 
its range by habitat loss (i.e., sea ice recession). We have determined 
that there are no known regulatory mechanisms in place at the national 
or international level that directly and effectively address the 
primary threat to polar bears--the rangewide loss of sea ice habitat. 
We have determined that overutilization does not currently threaten the 
species throughout all or a significant portion of its range, but is 
exacerbating the effects of habitat loss for several populations and 
may become a more significant threat factor within the foreseeable 
future. We have determined that disease and predation, in particular 
intraspecific predation, and contaminants do not currently threaten the 
species throughout all or a significant portion of its range, but may 
become more significant threat factors for polar bear populations, 
especially those experiencing nutritional stress or declining 
population levels, within the foreseeable future.

Distinct Population Segment (DPS) and Significant Portion of the Range 
(SPR) Evaluation

    The Act defines an endangered species as a species in danger of 
extinction throughout all or a significant portion of its range, and a 
threatened species as a species that is likely to become an endangered 
species within the foreseeable future throughout all or a significant 
portion of its range.
    In our analysis for this final rule we initially evaluated the 
status of and threats to the species throughout its entire range. The 
polar bear is broadly distributed throughout the circumpolar Arctic, 
occurring in five countries and numbering from 20,000-25,000 in total 
population. The species has been delineated into 19 populations for 
management purposes by the PBSG (Aars et al. 2006, p. 33), and these 
populations have been aggregated into four ecoregions for population 
and habitat modeling exercises by Amstrup et al. (2007). In our 
evaluation of threats to the polar bear, we determined that populations 
are being affected, and will continue being affected, at different

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times, rates, and magnitudes depending on where they occur. Some of 
these differential effects can be distinguished at the ecoregional 
level, as demonstrated by Amstrup et al. (2007). On the basis of this 
evaluation, we determined that the entire species meets the definition 
of threatened under the Act due to the loss of sea ice habitat. The 
basis of this determination is captured within the analysis of each of 
the five listing factors, and the ``Finding'' immediately preceding 
this section.
    Recognizing the differences in the timing, rate, and magnitude of 
threats, we evaluated whether there were any specific areas or 
populations that may be disproportionately threatened such that they 
currently meet the definition of an endangered species versus a 
threatened species. We first considered whether listing one or more 
Distinct Population Segments (DPS) as endangered may be warranted. We 
then considered whether there are any significant portions of the polar 
bear's range (SPR) where listing the species as endangered may be 
warranted. Our DPS and SPR analyses follow.
    Our ``Policy Regarding the Recognition of Distinct Vertebrate 
Population Segments under the Act'' (61 FR 4725; February 7, 1996) 
outlines three elements that must be considered with regard to the 
potential recognition of a DPS as endangered or threatened: (1) 
Discreteness of the population segment in relation to the remainder of 
the species to which it belongs; (2) significance of the population 
segment in relation to the remainder of the taxon; and (3) conservation 
status of the population segment in relation to the Act's standards for 
listing (i.e., when treated as if it were a species, is the population 
segment endangered or threatened?).
    Under our DPS Policy, a population segment of a vertebrate species 
may be considered discrete if it satisfies either one of the following 
conditions: (1) It is markedly separated from other populations of the 
same taxon as a consequence of physical, physiological, ecological, or 
behavioral factors (quantitative measures of genetic or morphological 
discontinuity may provide evidence of this separation); or (2) it is 
delimited by international governmental boundaries within which 
differences in control of exploitation, management of habitat, 
conservation status, or regulatory mechanisms exist that are 
significant in light of section 4(a)(1)(D) of the Act.
    Genetic studies of polar bears have documented that within-
population genetic variation is similar to black and grizzly bears 
(Amstrup 2003, p. 590), but that among populations, genetic structuring 
or diversity is low (Paetkau et al. 1995, p. 347; Cronin et al. 2006, 
pp. 658-659). The latter has been attributed to extensive population 
mixing associated with large home ranges and movement patterns, as well 
as the more recent divergence of polar bears in comparison to grizzly 
and black bears (Talbot and Shields 1996a, p. 490; Talbot and Shields 
1996b, p. 574; Paetkau et al. 1999, p. 1580). Genetic analyses support 
delineated boundaries between some populations (Paetkau et al. 1999, p. 
1,571; Amstrup 2003, p. 590), while confirming the existence of overlap 
and mixing among others (Paetkau et al. 1999, p. 1,571; Cronin et al. 
2006, p. 655). We have concluded that these small genetic differences 
are not sufficient to distinguish population segments under the DPS 
Policy. Moreover, there are no morphological or physiological 
differences across the range of the species that may indicate 
adaptations to environmental variations. Although polar bears within 
different populations or ecoregions (as defined by Amstrup et al. 2007) 
may have minor differences in demographic parameters, behavior, or life 
history strategies, in general polar bears have a similar dependence 
upon sea ice habitats, rely upon similar prey, and exhibit similar life 
history characteristics throughout their range.
    Consideration might be given to utilizing international boundaries 
to satisfy the discreteness portion of the DPS Policy. However, each 
range country shares populations with other range countries, and many 
of the shared populations are also co-managed. Given that the threats 
to the polar bear's sea ice habitat is global in scale and not limited 
to the confines of a single country, and that populations are being 
managed collectively by the range countries (through bi-lateral and 
multi-lateral agreements), we do not find that differences in 
conservation status or management for polar bears across the range 
countries is sufficient to justify the use of international boundaries 
to satisfy the discreteness criterion of the DPS Policy. Therefore, we 
conclude that there are no population segments that satisfy the 
discreteness criterion of the DPS Policy. As a consequence, we could 
not identify any geographic areas or populations that would qualify as 
a DPS under our 1996 DPS Policy (61 FR 4722).
    Having determined that the polar bear meets the definition of a 
threatened species rangewide and that there are no populations that 
meet the discreteness criteria under our DPS policy (and, therefore, 
that there are no Distinct Population Segments for the polar bear), we 
then considered whether there are any significant portions of its range 
where the species is in danger of extinction.
    On March 16, 2007, a formal opinion was issued by the Solicitor of 
the Department of the Interior, ``The Meaning of `In Danger of 
Extinction Throughout All or a Significant Portion of Its Range''' 
(USDI 2007c). We have summarized our interpretation of that opinion and 
the underlying statutory language below. A portion of a species' range 
is significant if it is part of the current range of the species and it 
contributes substantially to the representation, resiliency, or 
redundancy of the species. The contribution must be at a level such 
that its loss would result in a decrease in the ability to conserve the 
species.
    Some may argue that lost historical range should be considered by 
the Service when evaluating effects posed to a significant portion of 
the species' range. While we disagree with this argument, we note that 
the polar bear currently occupies its entire historical range.
    In determining whether a species is threatened or endangered in a 
significant portion of its range, we first identify any portions of the 
range of the species that warrant further consideration. The range of a 
species can theoretically be divided into portions in an infinite 
number of ways. However, there is no purpose to analyzing portions of 
the range that are not reasonably likely to be significant and 
threatened or endangered. To identify those portions that warrant 
further consideration, we determine whether there is substantial 
information indicating that (i) the portions may be significant and 
(ii) the species may be in danger of extinction there or likely to 
become so within the foreseeable future. In practice, a key part of 
this analysis is whether the threats are geographically concentrated in 
some way. If the threats to the species are essentially uniform 
throughout its range, no portion is likely to warrant further 
consideration. Moreover, if any concentration of threats applies only 
to portions of the range that are unimportant to the conservation of 
the species, such portions will not warrant further consideration.
    If we identify any portions that warrant further consideration, we 
then determine whether in fact the species is threatened or endangered 
in any significant portion of its range. Depending on the biology of 
the species, its range, and the threats it faces, it may be more 
efficient for the Service to

[[Page 28295]]

address the significance question first, or the status question first. 
Thus, if the Service determines that a portion of the range is not 
significant, the Service need not determine whether the species is 
threatened or endangered there. If the Service determines that the 
species is not threatened or endangered in a portion of its range, the 
Service need not determine if that portion is significant. If the 
Service determines that both a portion of the range of a species is 
significant and the species is threatened or endangered there, the 
Service will specify that portion of the range as threatened or 
endangered pursuant to section 4(c)(1) of the Act.
    The terms ``resiliency,'' ``redundancy,'' and ``representation'' 
are intended to be indicators of the conservation value of portions of 
the range. Resiliency of a species allows the species to recover from 
periodic disturbance. A species will likely be more resilient if large 
populations exist in high-quality habitat that is distributed 
throughout the range of the species in such a way as to capture the 
environmental variability found within the range of the species. In 
addition, the portion may contribute to resiliency for other reasons--
for instance, it may contain an important concentration of certain 
types of habitat that are necessary for the species to carry out its 
life-history functions, such as breeding, feeding, migration, 
dispersal, or wintering. Redundancy of populations may be needed to 
provide a margin of safety for the species to withstand catastrophic 
events. This does not mean that any portion that provides redundancy is 
a significant portion of the range of a species. The idea is to 
conserve enough areas of the range such that random perturbations in 
the system act on only a few populations. Therefore, each area must be 
examined based on whether that area provides an increment of redundancy 
that is important to the conservation of the species. Adequate 
representation ensures that the species' adaptive capabilities are 
conserved. Specifically, the portion should be evaluated to see how it 
contributes to the genetic diversity of the species. The loss of 
genetically based diversity may substantially reduce the ability of the 
species to respond and adapt to future environmental changes. A 
peripheral population may contribute meaningfully to representation if 
there is evidence that it provides genetic diversity due to its 
location on the margin of the species' habitat requirements.
    To determine whether any portions of the range of the polar bear 
warrant further consideration as possible endangered significant 
portions of the range, we reviewed the entire supporting record for 
this final listing determination with respect to the geographic 
concentration of threats and the significance of portions of the range 
to the conservation of the species. As previously mentioned, we 
evaluated whether substantial information indicated that (i) the 
portions may be significant and (ii) the species in that portion may 
currently be in danger of extinction. We recognize that the level, 
rate, and timing of threats are uneven across the Arctic and, thus, 
that polar bear populations will be affected at different rates and 
magnitudes depending on where they occur and the resiliency of each 
specific population. On this basis, we determined that some portions of 
the polar bear's range might warrant further consideration as possible 
endangered significant portions of the range.
    To determine which areas may warrant further consideration, we 
initially evaluated the four ecoregions defined by Amstrup et al. 
(2007), each of which consists of a subset of the 19 IUCN-defined 
management populations, plus a new population--the Queen Elizabeth 
Islands--created by the authors. The four ecoregions are: (1) the 
Seasonal Ice ecoregion; (2) the Archipelago ecoregion of the central 
Canadian Arctic; (3) the polar basin Divergent ecoregion; and (4) the 
polar basin Convergent ecoregion. On the basis of observational results 
from long-term studies of polar bear populations and sea ice 
conditions, plus projections from GCM climate simulations and the 
results of preliminary Carrying Capacity and Bayesian Network modeling 
exercises by Amstrup et al. (2007), we have determined that there is 
substantial information that polar bear populations in the Seasonal Ice 
and polar basin Divergent ecoregions may face a greater level of threat 
than populations in the Archipelago and polar basin Convergent 
ecoregions (see detailed discussion under Factor A). The large 
geographic area included in each of these ecoregions, plus the 
substantial proportion of the total polar bear population inhabiting 
those ecoregions, also indicate that they may be significant portions 
of the range. Having met these two initial tests, a further evaluation 
was deemed necessary to determine if these two portions of the range 
are both significant and endangered (that analysis follows below). We 
determined that the Archipelago and polar Convergent ecoregions do not 
satisfy the two initial tests, because there is not substantial 
information to suggest that the species in those portions may currently 
be in danger of extinction.
    After reviewing the four ecoregions, we proceeded to an evaluation 
of the 19 populations delineated for management purposes by the IUCN 
PBSG (Aars et al. 2006, p. 33) plus the Queen Elizabeth Island 
population created by Amstrup et al. (2007). For fourteen of the PBSG-
defined populations, population status is considered stable, 
increasing, or data deficient, and there is not substantial information 
indicating that they may currently be in danger of extinction. We 
eliminated these populations from further consideration. We also 
eliminated the Queen Elizabeth Island population because there is no 
current evidence of decline in the population, and because it occurs in 
the polar basin Convergent ecoregion where sea ice is projected to 
persist longest into the future (along with the Archipelago ecoregion). 
Thus, there is not substantial information indicating that this 
population may currently be in danger of extinction. For the remaining 
five populations, there is some information indicating actual or 
projected population declines according to the most recent 
subpopulation viability analysis conducted by the PBSG (i.e., Southern 
Beaufort Sea, Norwegian Bay, Western Hudson Bay, Kane Basin, Baffin 
Bay) (Aars et al. 2006, pp. 34-35). Two of these populations--Norwegian 
Bay and Kane Basin--occur within the Archipelago ecoregion, and are 
small both in terms of geographic area included within their boundaries 
and number of polar bears in the population. Even if these two 
populations are considered together, the overall geographic area they 
occupy and overall population size are still small. On this basis we 
determined that these two populations do not satisfy one portion of the 
initial test, because there is not substantial information to suggest 
that these areas are significant portions of the range. In addition, 
the two populations occur in the Archipelago ecoregion, where sea ice 
is projected to persist the longest into the future. In addition, 
available population estimates for these two populations are less 
reliable because they are older (circa 1998) and are based on limited 
years and incomplete coverage of sampling. Because of the projected 
persistence of sea ice in this area throughout the foreseeable future, 
and the lack of reliable information on population trends, we have 
determined that there is not substantial information to indicate that 
these populations are currently in danger of extinction. Having not

[[Page 28296]]

satisfied either of the two initial tests, we have determined that 
these two populations do not warrant any further consideration in this 
analysis.
    The relatively larger area and population size of each of the three 
remaining populations--Southern Beaufort Sea, Western Hudson Bay, 
Baffin Bay--indicate that they may be significant portions of the 
range. For these three populations there is information indicating 
actual or potential population declines according to the most recent 
subpopulation viability analysis conducted by the PBSG (Baffin Bay) and 
other recent studies (Regehr et al. 2007a for Western Hudson Bay; 
Regehr et al. 2007b for Southern Beaufort Sea), as well as projected 
population declines based on recent modeling exercises (Hunter et al. 
2007; Amstrup et al. 2007). Having met these two initial tests, a 
further evaluation was deemed necessary to determine if these three 
populations are both significant and endangered (that analysis follows 
below). Based on our review of the record, we did not find substantial 
information indicating that any other portions of the polar bear's 
range might be considered significant and qualify as endangered.
    Having identified the five portions of the range that warrant 
further consideration (two ecoregions and three populations), we then 
proceeded to determine whether any of those portions are both 
significant and endangered. We initially discuss our evaluation of the 
two ecoregions identified above, and then proceed to discuss our 
evaluation of the three populations identified above.
    On an ecoregional level, the most significant results suggesting 
that the two ecoregions may be endangered comes from the results of 
Bayesian network modeling (BM) exercises by Amstrup et al. (2007). In 
particular, the BM exercise results suggest that polar bear populations 
in the Seasonal Ice and polar basin Divergent ecoregions may be lost by 
the mid-21st century given rates of sea ice recession projected in the 
10-GCM ensemble used by the authors. As previously discussed above 
under the heading ``Bayesian Network Model'' within Factor A, we 
believe that this initial effort has several limitations that reduce 
our confidence in the actual numerical probabilities associated with 
each outcome of the BM, as opposed to the general direction and 
magnitude of the projected outcomes. The BM analysis is a preliminary 
effort that requires additional development (Amstrup et al. 2007, p. 
27). The current prototype is based on qualitative input from a single 
expert, and input from additional polar bear experts is needed to 
advance the model beyond the alpha prototype stage. There are also 
uncertainties associated with statistical estimation of various 
parameters such as the extent of sea ice or size of polar bear 
populations (Amstrup et al. 2007, p. 23). In addition, the BM needs 
further refinement to develop variance estimates to go with its 
outcomes. Because of these uncertainties associated with the complex 
BM, it is more appropriate to focus on the general direction and 
magnitude of the projected outcomes rather than the actual numerical 
probabilities associated with each outcome. Because of these 
limitations, we have determined that the BM model outcomes are not a 
sufficient basis, in light of the other available scientific 
information, to find that threats to polar bears currently warrant a 
determination of endangered status for the two ecoregions. However, 
despite these limitations, we also recognize that the BM results are a 
useful contribution to the overall weight of evidence and likelihood 
regarding changing sea ice, population stressors, and effects. We 
believe that the results are consistent with other available scientific 
information, including results of the CM (see discussion under 
``Carrying Capacity Model'' under Factor A), and quantitative evidence 
of the gradual rate of population decline in three populations within 
the ecoregions. We further note that, although these Seasonal Ice and 
polar basin Divergent ecoregions face differential threats, both 
ecoregions currently are estimated to have large numbers of polar 
bears, and there is no evidence of any population currently undergoing 
a precipitous decline. Therefore, we find that the polar bear is not 
currently in danger of extinction in either the Seasonal Ice ecoregion 
or the polar basin Divergent ecoregion.
    The three populations identified above as actually or potentially 
declining are the Western Hudson Bay, Southern Beaufort Sea, and Baffin 
Bay populations. Over an 18-year period, Regehr et al. (2007, p. 2,673) 
documented a statistically significant decline in the Western Hudson 
Bay polar bear population of 22 percent. For this period, the mean 
annual growth rate was 0.986 (with a 95 percent confidence interval of 
0.978-0.995), indicative of a gradual population decline. The decline 
has been attributed primarily to the effects of climate change (earlier 
break-up of sea ice in the spring), with harvest also playing a role 
(see discussion of ``Western Hudson Bay'' under Factor A). A reduction 
in harvest quota in this population (from 54 to 38) for the 2007-2008 
harvest season might begin to reduce the effect of harvest; however, we 
expect continued population declines from earlier and earlier break-up 
of sea ice and corresponding longer fasting periods of bears on land 
(Stirling and Parkinson 2006). Nonetheless, we note that the Western 
Hudson Bay population remains greater than 900 bears, and that 
reproduction and recruitment are still occurring in the population 
(Regehr et al. 2006). Because the current rate of decline for the 
Western Hudson Bay population is gradual rather than precipitous, 
reproduction and recruitment are still occurring, and the current size 
of the population remains reasonably large, we have determined that the 
population is not currently in danger of extinction, but is likely to 
become so within the foreseeable future.
    The apparent decline in the Southern Beaufort Sea population, 
documented over a 20-year period, has not been demonstrated to be 
statistically significant. However, available information indicates 
that there will be a statistically-significant population decline in 
the coming decades. Hunter et al. (2007) conducted a sophisticated 
demographic analysis of the Southern Beaufort Sea population using both 
deterministic and stochastic demographic models, and parameters 
estimated from capture-recapture data collected between 2001 and 2006. 
The authors focused on measures of long-term population growth rate and 
on projections of population size over the next 100 years. Taking the 
average observed frequency of bad sea ice years (0.21), they predicted 
a gradual population decline of about one percent per year (similar to 
the rate of decline observed in Western Hudson Bay), and an extinction 
probability of around 35-40 percent at year 45 (see Figure 14 of Hunter 
et al. 2007). However, the precision of vital rates used in the 
analysis (estimated by Regehr et al. (2007b, pp. 17-18)) was subject to 
large degrees of sampling and model selection uncertainty (Hunter et 
al. 2007, p. 6), the length of the study period (5 years) was short, 
and the spatial resolution of the GCMs at the scale of the southern 
Beaufort Sea is less reliable than at the scale of the entire range of 
the polar bear. These sources of uncertainty lead us to have greater 
confidence in the general direction and magnitude of the trend of the 
model outcomes in Hunter et al. (2007) than in the specific percentages 
associated with each

[[Page 28297]]

outcome. In addition, we note that the Southern Beaufort Sea population 
remains fairly large, that reproduction and recruitment is still 
occurring in the population, and that changes in the sea ice have not 
yet been associated with changes in the size of the population (Regehr 
et al. 2007, p. 2). These results all indicate that this population is 
not currently in danger of extinction but is likely to become so in the 
foreseeable future.
    As regards Baffin Bay, the recent population estimates of 2,074 
bears in 1998 and 1,546 bears in 2004 have limited reliability because 
of the population survey methods used. There is clear evidence that the 
population has been overharvested (Aars et al. 2006). Although the PBSG 
subpopulation viability analysis projects a declining trend, most 
likely as a result of overharverst, there is no reliable estimate of 
population trend based on valid population survey results. In recent 
years, some efforts have been made to reduce harvest of the Baffin Bay 
population. Greenland put a quota system in place for Baffin Bay in 
2006; its current quota is 75 bears. Stirling and Parkinson (2006, p. 
268) have documented earlier spring sea ice break-up dates in Baffin 
Bay since 1978 (i.e., ice breakup has been occurring 6 to 7 days 
earlier per decade since late 1978). Earlier breakup is likely to lead 
to longer periods of fasting onshore, with concomitant effects on bear 
body condition as documented in other populations. However, there are 
no data on body condition of polar bears or the survival of cubs or 
subadults from Baffin Bay (Stirling and Parkinson 2006, p. 269) that 
would allow an analysis of the relationship between changes in body 
condition and changes in sea ice habitat. In terms of projecting sea 
ice trends in Baffin Bay in the foreseeable future, Overland and Wang 
(2007) evaluated a suite of the 12 most applicable GCMs, and found 
that, ``according to these models, Baffin Bay does not show significant 
ice loss by 2050.'' These results are at apparent odds with observed 
sea ice trends, which further complicates projecting future effects of 
sea ice loss on polar bears. Without statistically reliable indices of 
declines in survival, body condition indices, or population size, and 
with evidence of earlier spring breakup dates but equivocal information 
on future sea ice conditions, we cannot conclude that the species is 
currently in danger of extinction in Baffin Bay, but can conclude it is 
likely to become so in the foreseeable future.
    Therefore, on the basis of the discussion presented in the previous 
three paragraphs, we find that the polar bear populations of Western 
Hudson Bay, Southern Beaufort Sea, and Baffin Bay are not currently in 
danger of extinction, but are likely to become so in the foreseeable 
future.
    As a result, while the best scientific data available allows us to 
make a determination as to the rangewide status of the polar bear, we 
have determined that when analyzed on a population or even an ecoregion 
level, the available data show that there are no significant portions 
of the range in which the species is currently in danger of extinction. 
Because we find that the polar bear is not endangered in the five 
portions of the range that we previously determined to warrant further 
consideration (two ecoregions and three populations), we need not 
address the question of significance for those five portions.

Critical Habitat

    Critical habitat is defined in section 3(5) of the Act as: (i) the 
specific areas within the geographical area occupied by a species, at 
the time it is listed in accordance with the Act, on which are found 
those physical or biological features (I) essential to the conservation 
of the species and (II) that may require special management 
considerations or protection; and (ii) specific areas outside the 
geographical area occupied by a species at the time it is listed, upon 
a determination that such areas are essential for the conservation of 
the species. ``Conservation'' is defined in section 3(3) of the Act as 
meaning the use of all methods and procedures needed to bring the 
species to the point at which listing under the Act is no longer 
necessary. The primary regulatory effect of critical habitat is the 
requirement, under section 7(a)(2) of the Act, that Federal agencies 
shall ensure that any action they authorize, fund, or carry out is not 
likely to result in the destruction or adverse modification of 
designated critical habitat.
    Section 4(a)(3) of the Act and implementing regulations (50 CFR 
424.12) require that, to the maximum extent prudent and determinable, 
we designate critical habitat at the time a species is determined to be 
endangered or threatened. Critical habitat may only be designated 
within the jurisdiction of the United States, and may not be designated 
for jurisdictions outside of the United States (50 CFR 424(h)). Our 
regulations (50 CFR 424.12(a)(1)) state that designation of critical 
habitat is not prudent when one or both of the following situations 
exist: (1) the species is threatened by taking or other activity and 
the identification of critical habitat can be expected to increase the 
degree of threat to the species; or (2) such designation of critical 
habitat would not be beneficial to the species. Our regulations (50 CFR 
424.12(a)(2)) further state that critical habitat is not determinable 
when one or both of the following situations exist: (1) Information 
sufficient to perform required analysis of the impacts of the 
designation is lacking; or (2) the biological needs of the species are 
not sufficiently well known to permit identification of an area as 
critical habitat.
    Delineation of critical habitat requires, within the geographical 
area occupied by the polar bear, identification of the physical and 
biological features essential to the conservation of the species. In 
general terms, physical and biological features essential to the 
conservation of the polar bear may include (1) annual and perennial 
marine sea ice habitats that serve as a platform for hunting, feeding, 
traveling, resting, and to a limited extent, for denning, and (2) 
terrestrial habitats used by polar bears for denning and reproduction 
for the recruitment of new animals into the population, as well as for 
seasonal use in traveling or resting. The most important polar bear 
life functions that occur in these habitats are feeding (obtaining 
adequate nutrition) and reproduction. These habitats may be influenced 
by several factors and the interaction among these factors, including: 
(1) water depth; (2) atmospheric and oceanic currents or events; (3) 
climatologic phenomena such as temperature, winds, precipitation and 
snowfall; (4) proximity to the continental shelf; (5) topographic 
relief (which influences accumulation of snow for denning); (6) 
presence of undisturbed habitats; and (7) secure resting areas that 
provide refuge from extreme weather or other bears or humans. Unlike 
some other marine mammal species, polar bears generally do not occur at 
high-density focal areas such as rookeries and haulout sites. However, 
certain terrestrial areas have a history of higher use, such as core 
denning areas, or are experiencing an increasing tendancy of use for 
resting, such as coastal areas during the fall open water phase for 
which polar bear use has been increasing in duration for additional and 
expanded areas. During the winter period, when energetic demands are 
the greatest, nearshore lead systems (linear openings or cracks in the 
sea ice) and emphemeral or recurrent polynyas (areas of open sea 
surrounded by sea ice) are areas of importance for seals

[[Page 28298]]

and, correspondingly for polar bears that hunt seals for nutrition. 
During the spring period, nearshore lead systems continue to be 
important habitat for bears for hunting seals and feeding. Also the 
shorefast ice zone where ringed seals construct subnivean birth lairs 
for pupping is an important feeding habitat during this season. In 
northern Alaska, while denning habitat is more diffuse than in other 
areas where core, high-density denning has been identified, certain 
areas such as barrier islands, river bank drainages, much of the North 
Slope coastal plain (including the Arctic NWR), and coastal bluffs that 
occur at the interface of mainland and marine habitat receive 
proportionally greater use for denning than other areas. Habitat 
suitable for the accumulation of snow and use for denning has been 
delineated on the North Slope.
    While information regarding important polar bear life functions and 
habitats associated with these functions has expanded greatly in Alaska 
during the past 20 years, the identification of specific physical and 
biological features and specific geographic areas for consideration as 
critical habitat is complicated, and the future values of these 
habitats may change in a rapidly changing environment. Arctic sea ice 
provides a platform for critical life-history functions, including 
hunting, feeding, travel, and nuturing cubs. That habitat is projected 
to be significantly reduced within the next 45 years, and some models 
project complete absence of sea ice during summer months in shorter 
timeframes.
    A careful assessment of the designation of marine areas as critical 
habitat will require additional time to fully evaluate physical and 
biological features essential to the conservation of the polar bear and 
how those features are likely to change over the foreseeable future. In 
addition, near-shore and terrestrial habitats that may qualify for 
designation as critical habitat will require a similar thorough 
assessment and evaluation in light of projected climate change and 
other threats. Additionally, we have not gathered sufficient economic 
and other data on the impacts of a critical habitat designation. These 
factors must be considered as part of the designation procedure. Thus, 
we find that critical habitat is not determinable at this time.

Available Conservation Measures

    The Service will continue to work with other countries that have 
jurisdiction in the Arctic, the IUCN/SSC Polar Bear Specialist Group, 
U.S. government agencies (e.g., NASA, NOAA), species experts, Native 
organizations, and other parties as appropriate to consider new 
information as it becomes available to track the status of polar bear 
populations over time, to develop a circumpolar monitoring program for 
the species, and to develop management actions to conserve the polar 
bear. Using current ongoing and future monitoring programs for the 19 
IUCN-designated populations we will continue to evaluate the status of 
the species in relation to its listing under the Act. In addition, 
status of domestic populations will continue to be evaluated as 
required under the MMPA.
    Conservation measures provided to species listed as endangered or 
threatened under the Act include recognition of the status, increased 
priority for research and conservation funding, recovery actions, 
requirements for Federal protection, and prohibitions against certain 
activities. Recognition through listing results in public awareness and 
conservation actions by Federal, State, and local agencies, private 
organizations, and individuals. The Act provides for possible land 
acquisition and cooperation with the States, and for conservation 
actions to be carried out for listed species.
    The listing of the polar bear will lead to the development of a 
recovery plan for this species in Alaska. The recovery plan will bring 
together international, Federal, State, and local agencies, and private 
efforts, for the conservation of this species. A recovery plan for 
Alaska will establish a framework for interested parties to coordinate 
activities and to cooperate with each other in conservation efforts. 
The plan will set recovery priorities, identify responsibilities, and 
estimate the costs of the tasks necessary to accomplish the priorities. 
Under section 6 of the Act, we would be able to grant funds to the 
State of Alaska for management actions promoting the conservation of 
the polar bear.
    Additionally, the Service will pursue conservation strategies among 
all countries that share management of polar bears. The existing 
multilateral agreement provides an international framework to pursue 
such strategies, and the outcome of the June 2007 meeting of polar bear 
range countries (held at the National Conservation Training Center in 
West Virginia) clearly documents the shared interest by all to pursue 
such an effort. Range-wide strategies will be particularly important as 
the sea ice habitat likely to persist the longest is not in U.S. 
jurisdiction and collaborative efforts to support ongoing research and 
management actions for purposes of restoring or supplementing the most 
dramatically affected population will be important. The PBSG is 
recognized as the technical advisor for the 1973 Agreement for the 
Conservation of Polar Bears and provides recommendations to each of the 
range states on conservation and management; recommendations from this 
group will be sought throughout the entire process.
    Section 7(a) of the Act, as amended, requires Federal agencies to 
evaluate their actions with respect to any species that is listed as 
endangered or threatened and with respect to its critical habitat, if 
any is designated. Regulations implementing this interagency 
cooperation provision of the Act are codified at 50 CFR part 402. For 
threatened species such as the polar bear, section 7(a)(2) of the Act 
requires Federal agencies to ensure that activities they authorize, 
fund, or carry out are not likely to jeopardize the continued existence 
of the species. If a Federal action may affect a polar bear, the 
responsible Federal agency must consult with us under the provisions of 
section 7(a)(2) of the Act.
    Several Federal agencies are expected to have involvement under 
section 7 of the Act regarding the polar bear. The National Marine 
Fisheries Service may become involved, such as if a joint rulemaking 
for the incidental take of marine mammals is undertaken. The EPA may 
become involved through its permitting authority under the Clean Water 
Act and Clean Air Act for activities conducted in Alaska. The U.S Army 
Corps of Engineers may become involved through its responsibilities and 
permitting authority under section 404 of the Clean Water Act and 
through future development of harbor projects. The MMS may become 
involved through administering their programs directed toward offshore 
oil and gas development, and the BLM for onshore activities in NPRA. 
The Denali Commission may be involved through its potential funding of 
fuel and power generation projects. The U.S. Coast Guard may become 
involved through their deployment of icebreakers in the Arctic Ocean.
    Much of Alaska oil and gas development occurs within the range of 
polar bears, and the Service has worked effectively with the industry 
for a number of years to minimize impacts to polar bears through 
implementation of the incidental take program authorized under the 
MMPA. Under the MMPA, incidental take cannot be authorized unless the 
Service finds that any take that is reasonably likely to occur will 
have no more than a negligible impact on the species. Incidental take

[[Page 28299]]

authorization has been in place for the Beaufort Sea region since 1993 
and for the Chukchi Sea in 2006 and 2007. New MMPA incidental take 
authorization covering oil and gas exploration activities in the 
Chukchi Sea was proposed in June 2007. Mitigation measures required 
under these authorizations minimize potential impacts to polar bears 
and ensure that any take remains at the negligible level; these 
measures are implemented on a case-by-case basis through Letters of 
Authorization (LOAs) under the MMPA. Because the MMPA negligible impact 
standard is a tighter management standard than ensuring that an 
activity is not likely to jeopardize the continued existence of the 
species under section 7 of the Act, we do not anticipate that any 
entity holding incidental take authorization for polar bears under the 
MMPA and in compliance with all mitigation measures under that 
authorization will be required to implement further measures under the 
section 7 consultation process.

Regulatory Implications for Consultations under Section 7 of the Act

    When a species is listed as threatened under the Act, section 
7(a)(2) provides that Federal agencies must insure that any actions 
they authorize, fund, or carry out are not likely to jeopardize the 
continued existence of any listed species or result in the destruction 
or adverse modification of designated critical habitat. Furthermore, 
under the authority of section 4(d), the Secretary shall establish 
regulatory provisions on the take of threatened species that are 
``necessary and advisable to provide for the conservation of the 
species'' (16 U.S.C. 1533(d)).
    The coverage of the section 9 taking prohibition is much broader 
than a simple prohibition against killing an individual of the species. 
Section 3(19) of the Act defines the term ``take'' as ``* * * harass, 
harm, pursue, hunt, shoot, wound, kill, trap, capture, or collect, or 
attempt to engage in any such conduct.'' Federal regulations 
promulgated by the Service (50 CFR 17.3) define the terms ``harm'' and 
``harass'' as:
    Harass in the definition of ``take'' in the Act means an 
intentional or negligent act or omission which creates the likelihood 
of injury to wildlife by annoying it to such an extent as to 
significantly disrupt normal behavioral patterns which include, but are 
not limited to, breeding, feeding, or sheltering. This definition, when 
applied to captive wildlife does not include generally accepted: (1) 
animal husbandry practices that meet or exceed the minimum standards 
for facilities and care under the Animal Welfare Act, (2) breeding 
procedures, or (3) provisions of veterinary care for confining, 
tranquilizing, or anesthetizing, when such practices, procedures, or 
provisions are not likely to result in injury to the wildlife.
    Harm in the definition of ``take'' in the Act means an act that 
actually kills or injures wildlife. Such act may include significant 
habitat modification or degradation where it actually kills or injures 
wildlife by significantly impairing essential behaviorial patterns, 
including breeding, feeding, or sheltering.
    Certain levels of incidental take may be authorized through 
provisions under section 7(b)(4) and (o)(2) (incidental take statements 
for Federal agency actions) and section 10(a)(1)(B) (incidental take 
permits).
    In making a determination to authorize incidental take under 
section 7 or section 10, the Service must assess the effects of the 
proposed action to evaluate the potential negative and positive impacts 
that are expected to occur as a result of the action. Under Section 7, 
this would be done through a consultation between the Service and the 
Federal agency on a specific proposed agency action. Section 7 
consultation regulations generally limit the Service's review of the 
effects of the proposed action to the direct and indirect effects of 
the action and any activities that are interrelated or interdependent 
with the proposed action. ``Indirect'' effects are caused by the 
proposed action, later in time, and are ``reasonably certain to 
occur.'' Essentially, the Service evaluates those effects that would 
not occur ``but for'' the action under consultation and that are also 
reasonably certain to occur. Cumulative effects, which are the effects 
of future non-Federal actions that are also reasonably certain to occur 
within the action area of the proposed action, must also be taken into 
consideration. The direct, indirect, and cumulative effects are then 
analyzed along with the status of the species and the environmental 
baseline to determine whether the action under consultation is likely 
to reduce appreciably both the survival and recovery of the listed 
species or result in the destruction or adverse modification of 
critical habitat. If the Service determines that the action is not 
likely to jeopardize the continued existence of a listed species, a 
``no jeopardy'' opinion will be issued, along with an incidental take 
statement. The purpose of the incidental take statement is to identify 
the amount or extent of take that is reasonably likely to result from 
the proposed action and to minimize the impact of any take through 
reasonable and prudent measures (RPMs). The regulations require, 
however, that any RPM's be only a ``minor change'' to the proposed 
action. If the Federal agency and any applicant comply with the terms 
and conditions of the incidental take statement, then section 7(o)(2) 
of the Act provides an exception to the take prohibition.
    The 9th Circuit Court of Appeals has determined that the Service 
cannot use the consultation process or the issuance of an Incidental 
Take Statement as a form of regulation limiting what are otherwise 
legal activities by action agencies, if no incidental take is 
reasonably likely to occur as a result of the Federal action (Arizona 
Cattle Growers' Association v. U.S. Fish and Wildlife Service, 273 F.3d 
1229 (9th Cir. 2001)). In that case, the court reviewed several 
biological opinions that were the result of consultations on numerous 
grazing permits. The 9th Circuit analyzed the Service's discussion of 
effects and the incidental take statements for several specific grazing 
allotments. The court found that the Service, in some allotments, 
assumed there would be ``take'' without explaining how the agency 
action (in this case, cattle grazing) would cause the take of specific 
individuals of the listed species. Further, for other permits the court 
did not see evidence or argument to demonstrate how cattle grazing in 
one part of the permit area would take listed species in another part 
of that permit area. The court concluded that the Service must 
``connect the dots'' between its evaluation of effects of the action 
and its assessment of take. That is, the Service cannot simply 
speculate that take may occur. The Service must first articulate the 
causal connection between the effects of the action under consultation 
and the anticipated take. It must then demonstrate that the take is 
reasonably likely to occur.
    The significant cause of the decline of the polar bear, and thus 
the basis for this action to list it as a threatened species, is the 
loss of arctic sea ice that is expected to continue to occur over the 
next 45 years. The best scientific information available to us today, 
however, has not established a causal connection between specific 
sources and locations of emissions to specific impacts posed to polar 
bears or their habitat.
    Some commenters to the proposed rule suggested that the Service 
should require other agencies (e.g., the Environmental Protection 
Agency) to

[[Page 28300]]

regulate emissions from all sources, including automobile and power 
plants. The best scientific information available today would neither 
allow nor require the Service to take such action.
    First, the primary substantive mandate of section 7(a)(2)--the duty 
to avoid likely jeopardy to an endangered or threatened species--rests 
with the Federal action agency and not with the Service. The Service 
consults with the Federal action agency on proposed Federal actions 
that may affect an endangered or threatened species, but its 
consultative role under section 7 does not allow for encroachment on 
the Federal action agency's jurisdiction or policy-making role under 
the statutes it administers.
    Second, the Federal action agency decides when to initiate formal 
consultation on a particular proposed action, and it provides the 
project description to the Service. The Service may request the Federal 
action agency to initiate formal consultation for a particular proposed 
action, but it cannot compel the agency to consult, regardless of the 
type of action or the magnitude of its projected effects.
    Recognizing the primacy of the Federal action agency's role in 
determining how to conform its proposed actions to the requirements of 
section 7, and taking into account the requirement to examine the 
``effects of the action'' through the formal consultation process, the 
Service does not anticipate that the listing of the polar bear as a 
threatened species will result in the initiation of new section 7 
consultations on proposed permits or licenses for facilities that would 
emit GHGs in the conterminous 48 States. Formal consultation is 
required for proposed Federal actions that ``may affect'' a listed 
species, which requires an examination of whether the direct and 
indirect effects of a particular action meet this regulatory threshold. 
GHGs that are projected to be emitted from a facility would not, in and 
of themselves, trigger formal section 7 consultation for a particular 
licensure action unless it is established that such emissions 
constitute an ``indirect effect'' of the proposed action. To constitute 
an ``indirect effect,'' the impact to the species must be later in 
time, must be caused by the proposed action, and must be ``reasonably 
certain to occur'' (50 CFR 402.02 (definition of ``effects of the 
action'')). As stated above, the best scientific data available today 
are not sufficient to draw a causal connection between GHG emissions 
from a facility in the conterminous 48 States to effects posed to polar 
bears or their habitat in the Arctic, nor are there sufficient data to 
establish that such impacts are ``reasonably certain to occur'' to 
polar bears. Without sufficient data to establish the required causal 
connection--to the level of ``reasonable certainty''--between a new 
facility's GHG emissions and impacts to polar bears, section 7 
consultation would not be required to address impacts to polar bears.
    A question has also been raised regarding the possible application 
of section 7 to effects posed to polar bears that may arise from oil 
and gas development activities conducted on Alaska's North Slope or in 
the Chukchi Sea. It is clear that any direct effects from oil and gas 
development operations, such as drilling activities, vehicular traffic 
to and from drill sites, and other on-site operational support 
activities, that pose adverse effects to polar bears would need to be 
evaluated through the section 7 consultation process. It is also clear 
that any ``indirect effects'' from oil and gas development activities, 
such as impacts from the spread of contaminants (accidental oil spills, 
or the unintentional release of other contaminants) that result from 
the oil and gas development activities and that are ``reasonably 
certain to occur,'' that flow from the ``footprint'' of the action and 
spread into habitat areas used by polar bears would also need to be 
evaluated through the section 7 consultation process.
    However, the future effects of any emissions that may result from 
the consumption of petroleum products refined from crude oil pumped 
from a particular North Slope drilling site would not constitute 
``indirect effects'' and, therefore, would not be considered during the 
section 7 consultation process. The best scientific data available to 
the Service today does not provide the degree of precision needed to 
draw a causal connection between the oil produced at a particular 
drilling site, the GHG emissions that may eventually result from the 
consumption of the refined petroleum product, and a particular impact 
to a polar bear or its habitat. At present there is a lack of 
scientific or technical knowledge to determine a relationship between 
an oil and gas leasing, development, or production activity and the 
effects of the ultimate consumption of petroleum products (GHG 
emissions). There are discernible limits to the establishment of a 
causal connection, such as uncertainties regarding the productive yield 
from an oil and gas field; whether any or all of such production will 
be refined for plastics or other products that will not be burned; what 
mix of vehicles or factories might use the product; and what mitigation 
measures would offset consumption. Furthermore, there is no traceable 
nexus between the ultimate consumption of the petroleum product and any 
particular effect to a polar bear or its habitat. In short, the 
emissions effects resulting from the consumption of petroleum derived 
from North Slope or Chukchi Sea oil fields would not constitute an 
``indirect effect'' of any federal agency action to approve the 
development of that field.

Other Provisions of the Act

    Section 9 of the Act, except as provided in sections 6(g)(2) and 10 
of the Act, prohibits take (within the United States and on the high 
seas) and import into or export out of the United States of endangered 
species. The Act defines take to mean harass, harm, pursue, hunt, 
shoot, wound, kill, trap, capture, or collect, or to attempt to engage 
in any such conduct. However, the Act also provides for the 
authorization of take and exceptions to the take prohibitions. Take of 
endangered wildlife species by non-Federal property owners can be 
permitted through the process set forth in section 10 of the Act. The 
Service has issued regulations (50 CFR 17.31) that generally afford to 
fish and wildlife species listed as threatened the prohibitions that 
section 9 of the Act establishes with respect to species listed as 
endangered.
    The Service may also develop a special rule specifically tailored 
to the conservation needs of a threatened species instead of applying 
the general threatened species regulations. In today's Federal Register 
we have published a special rule for the polar bear that generally 
adopts existing conservation regulatory requirements under the MMPA and 
the Convention on International Trade in Endangered Species of Wild 
Fauna and Flora (CITES) as the appropriate regulatory provisions for 
this threatened species.
    Section 10(e) of the Act provides an exemption for any Indian, 
Aleut, or Eskimo who is an Alaskan Native and who resides in Alaska to 
take a threatened or endangered species if such taking is primarily for 
subsistence purposes and the taking is not accomplished in a wasteful 
manner. Non-native permanent residents of an Alaska native village are 
also covered by this exemption, but since such persons are not covered 
by the similar exemption under the MMPA, take of polar bears for 
subsistence purposes by non-native permanent residents of an Alaskan 
native village would not be lawful. While the collaborative co-

[[Page 28301]]

management mechanisms to institute sustainable harvest levels are in 
place, the challenges of managing harvest for declining populations are 
new and will require extensive dialogue with the Alaska Native hunting 
community and their leadership organizations. Development of risk 
assessment models that describe the probability and effect of a range 
of harvest levels interrelated to demographic population life tables 
are needed. Any future consideration of harvest regulation will be done 
with the full involvement of the subsistence community through the 
Alaska Nanuuq Commission and North Slope Borough and should build upon 
the co-management approach to harvest management that we have developed 
through the Inupiat-Inuvialuit Agreement and which we will work to 
expand through the United States-Russia Bilateral Agreement. The 
Inupiat-Inuvialuit Agreement is a voluntary harvest agreement between 
the native peoples of Alaska and Canada who share access to the 
Southern Beaufort Sea polar bear population. The agreement includes 
harvest restrictions, including a quota. A 10-year review of the 
agreement published in 2002 revealed high compliance rates and support 
for the agreement. The United States-Russia Bilateral Agreement calls 
for the active involvement of the United States, Russian Federation, 
and native people of both countries in managing subsistence harvest. 
The Service is currently developing recommendations for the Bilateral 
Commission that will direct research and establish sustainable and 
enforceable harvest limits needed to address current potential 
population declines due to overharvest of the stock. Development of 
population estimates and harvest monitoring protocols must be developed 
in a cooperative bilateral manner. The Alaska Nanuuq Commission, the 
North Slope Borough, USGS, and the Alaska Department of Fish and Game 
(ADF&G) have indicated support for these future efforts and wish to be 
a part of implementation of this agreement.
    Under the section 10(e) exemption, nonedible byproducts of species 
taken pursuant to this section may be sold in interstate commerce when 
made into authentic native articles of handicrafts and clothing. It is 
illegal to possess, sell, deliver, carry, transport, or ship any such 
wildlife that has been taken illegally. Further, it is illegal for any 
person to commit, to solicit another person to commit, or cause to be 
committed, any of these acts. Certain exceptions to the prohibitions 
apply to our agents and State conservation agencies. See our special 
rule published in today's edition of the Federal Register that would 
align allowable activities with authentic native articles of 
handicrafts and clothing made from polar bear parts with existing 
provisions under the MMPA.
    Under the general threatened species regulations at 50 CFR 17.32, 
permits to carry out otherwise prohibited activities may be issued for 
particular purposes, including scientific purposes, enhancement of the 
propagation or survival of the species, zoological exhibitions, 
educational purposes, incidental take in the course of otherwise lawful 
activities, or special purposes consistent with the purposes of the 
Act. However, see today's Federal Register for our rule that presents 
provisions specifically tailored to the conservation needs of the polar 
bear that generally adopts provisions of the MMPA and CITES. Requests 
for copies of the regulations that apply to the polar bear and 
inquiries about prohibitions and permits may be addressed to the 
Endangered Species Coordinator, U.S. Fish and Wildlife Service, 1011 
East Tudor Road, Anchorage, AK 99503.
    It is our policy, published in the Federal Register on July 1, 1994 
(59 FR 34272), to identify, to the maximum extent practicable at the 
time a species is listed, those activities that would or would not 
likely constitute a violation of regulations at 50 CFR 17.31. The 
intent of this policy is to increase public awareness of the effects of 
the listing on proposed and ongoing activities within a species' range.
    For the polar bear we have not yet determined which, if any, 
provisions under section 9 would apply, provided these activities are 
carried out in accordance with existing regulations and permit 
requirements. Some permissible uses or actions have been identified 
below. Note that the special rule for polar bears (see the special rule 
published in today's Federal Register) affects certain activities 
otherwise regulated under the Act.
    (1) Possession and noncommercial interstate transport of authentic 
native articles of handicrafts and clothing made from polar bears taken 
for subsistence purposes in a nonwasteful manner by Alaska Natives;
    (2) Any action authorized, funded, or carried out by a Federal 
agency that may affect the polar bear, when the action is conducted in 
accordance with the terms and conditions of authorizations under 
section 101(a)(5) of the MMPA and the terms and conditions of an 
incidental take statement issued by us under section 7 of the Act;
    (3) Any action carried out for scientific purposes, to enhance the 
propagation or survival of polar bears, for zoological exhibitions, for 
educational purposes, or for special purposes consistent with the 
purposes of the Act that is conducted in accordance with the conditions 
of a permit issued by us under 50 CFR 17.32; and
    (4) Any incidental take of polar bears resulting from an otherwise 
lawful activity conducted in accordance with the conditions of an 
incidental take permit issued under 50 CFR 17.32. Non-Federal 
applicants may design a habitat conservation plan (HCP) for the species 
and apply for an incidental take permit. HCPs may be developed for 
listed species and are designed to minimize and mitigate impacts to the 
species to the greatest extent practicable. See also requirements for 
incidental take of a polar bear under (3) above.
    We believe the following activities could potentially result in a 
violation of the special rule for polar bears; however, possible 
violations are not limited to these actions alone:
    (1) Unauthorized killing, collecting, handling, or harassing of 
individual polar bears;
    (2) Possessing, selling, transporting, or shipping illegally taken 
polar bears or their parts;
    (3) Unauthorized destruction or alteration of denning, feeding, or 
resting habitats, or of habitats used for travel, that actually kills 
or injures individual polar bears by significantly impairing their 
essential behavioral patterns, including breeding, feeding, or 
sheltering; and
    (4) Discharge or dumping of toxic chemicals, silt, or other 
pollutants (i.e., sewage, oil, pesticides, and gasoline) into the 
marine environment that actually kills or injures individual polar 
bears by significantly impairing their essential behavioral patterns, 
including breeding, feeding, or sheltering.
    We will review other activities not identified above on a case-by-
case basis to determine whether they may be likely to result in a 
violation of 50 CFR 17.31. We do not consider these lists to be 
exhaustive and provide them as information to the public. You may 
direct questions regarding whether specific activities may constitute a 
violation of the Act to the Field Supervisor, U.S. Fish and Wildlife 
Service, Fairbanks Fish and Wildlife Field Office, 101 12th Avenue, Box 
110, Fairbanks, Alaska 99701.
    Regarding ongoing importation of sport-hunted polar bear trophies 
from Canada, under sections 101(a)(3)(B) and 102(b) of the MMPA, it is 
unlawful to

[[Page 28302]]

import into the United States any marine mammal that has been 
designated as a depleted species or stock unless the importation is for 
the purpose of scientific research or enhancement of the survival or 
recovery of the species. Under the MMPA, the polar bear will be a 
depleted species as of the effective date of the rule. Under sections 
102(b) and 101(a)(3)(B) of the MMPA therefore, as a depleted species, 
polar bears and their parts cannot be imported into the United States 
except for scientific research or enhancement. Therefore, sport-hunted 
polar bear trophies from Canada cannot be imported after the effective 
date of this listing rule. Nothing in the special rule for polar bears 
published in today's Federal Register affects these provisions under 
the MMPA.

Future Opportunities

    Earlier in the preamble to this final rule, we determined that 
polar bear habitat--principally sea ice--is declining throughout the 
species' range, that this decline is expected to continue for the 
foreseeable future, and that this loss threatens the species throughout 
all of its range. We also determined that there are no known regulatory 
mechanisms in place, and none that we are aware of that could be put in 
place, at the national or international level, that directly and 
effectively address the rangewide loss of sea ice habitat within the 
foreseeable future. We also acknowledged that existing regulatory 
mechanisms to address anthropogenic causes of climate change are not 
expected to be effective in counteracting the worldwide growth of GHG 
emissions within the foreseeable future, as defined in this rule.
    Fully aware of the current situation and projected trends within 
the foreseeable future, and recognizing the great challenges ahead of 
us, we remain optimistic that the future can be a bright one for the 
polar bear. The root causes and consequences of the loss of Arctic sea 
ice extend well beyond the five countries that border the Arctic and 
comprise the range of the polar bear, and will extend beyond the 
foreseeable future as determined in this rule. This is a global issue 
and will be resolved as the global community comes together and acts in 
concert to achieve that resolution. Polar bear range countries are 
working, individually and cooperatively, to conserve polar bears and 
alleviate stressors on polar bear populations that may exacerbate the 
threats posed by sea ice loss. The global community is also beginning 
to act more cohesively, by developing national and international 
regulatory mechanisms and implementing measures to mitigate the 
anthropogenic causes of climate change.
    In December 2007, the United States joined other Nations at the 
United Nations (UN) Climate Change Conference in Bali to launch a 
comprehensive ``roadmap'' for global climate negotiations. The Bali 
Action Plan is a critical step in moving the UN negotiation process 
forward toward a comprehensive and effective post-2012 arrangement by 
2009. (Please note that measures in the Bali Action Plan, in and of 
themselves, were not considered as offsetting or otherwise dimishing 
the risk of sea ice loss in our determination of the appropriate 
listing classification for the polar bear.) In December 2007, President 
Bush signed the Energy Independence and Security Act of 2007, which 
responded to his ``Twenty in Ten'' challenge in his 2006 State of the 
Union Address to improve vehicle fuel economy and increase alternative 
fuels. This bill will help improve energy efficiency and cut GHG 
emissions.
    With the world community acting in concert, we are confident the 
future of the polar bear can be secured.

National Environmental Policy Act

    We have determined that we do not need to prepare an environmental 
assessment or an environmental impact statement as defined under the 
authority of the National Environmental Policy Act of 1969, in 
connection with regulations adopted under section 4(a) of the Act. We 
published a notice outlining our reasons for this determination in the 
Federal Register on October 25, 1983 (48 FR 49244).

Government-to-Government Relationship with Tribes

    In accordance with the President's memorandum of April 29, 1994, 
``Government-to-Government Relations with Native American Tribal 
Governments'' (59 FR 22951), Executive Order 13175, Secretarial Order 
3225, and the Department of Interior's manual at 512 DM 2, we readily 
acknowledge our responsibility to communicate meaningfully with 
recognized Federal Tribes on a government-to-government basis. Since 
1997, we have signed cooperative agreements annually with The Alaska 
Nanuuq Commission (Commission) to fund their activities. The Commission 
was established in 1994 to represent the interests of subsistence users 
and Alaska Native polar bear hunters when working with the Federal 
government on the conservation of polar bears in Alaska. We attended 
Commission board meetings during the preparation of the proposed rule 
and subsequent public comment period, regularly briefing the board of 
commissioners and staff on relevant issues. We also requested the 
Commission to act as a peer reviewer of the Polar Bear Status Review 
(Schliebe et al. 2006a) and the proposed rule to list the species 
throughout its range (72 FR 1064). In addition to working closely with 
the Commission, we sent copies of the proposed rule (72 FR 1064) to, or 
contacted directly, 46 Alaska Native Tribal Councils and specifically 
requested their comments on the proposed listing action. As such, we 
believe that we have and will continue to coordinate with affected 
Tribal entities in compliance with the applicable Executive and 
Secretarial Orders.

References Cited

    A complete list of all references cited in this rule is available 
upon request. You may request a list of all references cited in this 
document from the Supervisor, Marine Mammals Management Office (see 
ADDRESSES section).

Authors

    The primary authors of this rule are Scott Schliebe, Marine Mammals 
Management Office (see ADDRESSES section), and Kurt Johnson, PhD, 
Branch of Listing, Endangered Species Program, Arlington, VA.

List of Subjects in 50 CFR Part 17

    Endangered and threatened species, Exports, Imports, Reporting and 
recordkeeping requirements, Transportation.

Final Regulation Promulgation

0
Accordingly, part 17, subchapter B of chapter I, title 50 of the Code 
of Federal Regulations, is amended as set forth below:

PART 17--[AMENDED]

0
1. The authority citation for part 17 continues to read as follows:

    Authority: 16 U.S.C. 1361-1407; 16 U.S.C. 1531-1544; 16 U.S.C. 
4201-4245; Pub. L. 99-625, 100 Stat. 3500; unless otherwise noted.
0
2. Amend Sec.  17.11(h) by adding an entry for ``Bear, polar'' in 
alphabetical order under MAMMALS, to the List of Endangered and 
Threatened Wildlife to read as follows:


Sec.  17.11  Endangered and threatened wildlife.

* * * * *
    (h) * * *

[[Page 28303]]



--------------------------------------------------------------------------------------------------------------------------------------------------------
                       Species                                                   Vertebrate
------------------------------------------------------                        population where                                    Critical     Special
                                                          Historic Range       endangered or          Status       When listed    habitat       rules
           Common name              Scientific name                              threatened
--------------------------------------------------------------------------------------------------------------------------------------------------------
             Mammals
 
                                                                     * * * * * * * *
Bear, polar.....................  Ursus maritimus....  U.S.A. (AK),         Entire.............  T                 ...........           NA           NA
                                                        Canada, Russia,
                                                        Denmark
                                                        (Greenland),
                                                        Norway.
 
                                                                     * * * * * * * *
--------------------------------------------------------------------------------------------------------------------------------------------------------


    Dated: May 14, 2008.
Dirk Kempthorne,
Secretary of the Interior.
[FR Doc. E8-11105 Filed 5-14-08; 3:15 pm]
BILLING CODE 4310-55-P