Order Code RL33941
Polar Bears: Proposed Listing Under the
Endangered Species Act
Updated March 30, 2007
Eugene H. Buck
Specialist in Natural Resources Policy
Resources, Science, and Industry Division

---

Polar Bears: Proposed Listing Under the
Endangered Species Act
Summary
The proposed listing of polar bears as threatened under the Endangered Species
Act (ESA; 16 U.S.C. §§1531 et seq.) highlights the intersection of two significant
issues currently before Congress — climate change and species protection.
According to the ESA, this listing decision rests solely on an interpretation of the
best available scientific understanding of the species and how it may be affected by
changes in its habitat.
Polar bears depend on Arctic sea ice, which most scientists acknowledge will
be affected by climate warming causing, at minimum, an earlier annual or seasonal
thaw and a later freeze of coastal sea ice. Globally, less than one-third of the 19
known or recognized polar bear populations are declining, more than one-third are
increasing or stable, while the remaining third have insufficient data available to
estimate population trends and their status has not been assessed. Two of these polar
bear populations occur within U.S. jurisdiction.
Polar bears are affected by climate change, contaminants, and subsistence and
sport hunting. Environmental organizations have voiced public concern that polar
bears were threatened by climate change. Scientists have confirmed that, in recent
decades, the extent of Arctic sea ice has declined significantly as the result of climate
warming: annual ice break-up in many areas is occurring earlier and freeze-up later,
Arctic sea ice is experiencing a continuing decline that cannot easily be reversed, and
some models project that Arctic sea ice will disappear completely by the second half
of this century. Three main groups of contaminants are implicated as potentially
threatening polar bears — petroleum hydrocarbons, persistent organic pollutants, and
heavy metals. The United States allows limited subsistence harvest of polar bears by
Alaska Natives. In Canada, Native hunters are permitted to allocate a limited portion
of the subsistence harvest to sport hunters. Under 1994 amendments to the MMPA,
U.S. citizens may obtain permits to import sport-harvested polar bear trophies from
Canada.
The Fish and Wildlife Service (FWS) has proposed listing polar bears as a
threatened species under ESA, acknowledging the increasing threats to their
existence. The FWS listing decision must be based solely on the best available
scientific and commercial information regarding five factors: habitat destruction,
overutilization, disease or predation, inadequacy of other regulatory mechanisms, and
other natural or manmade factors.
Controversy exists over how great a threat the changing climate might be to
polar bears and whether they might be able to adapt to these changing conditions.
Some point out that polar bears today are not coping with changing climate alone, but
also face a host of other human-induced factors — including shipping, oil and gas
exploration, contaminants, and reduced prey populations — that compound the threat
to their continued existence. There is also considerable uncertainty in estimates of
polar bear population numbers and trends as well as in our understanding of polar
bear habitat.

---

Contents
Background . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
Circumstances Affecting Polar Bears . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
Climate Change . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
Contaminants . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
Subsistence and Sport Harvest . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
Protection Efforts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
Controversy . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
List of Figures
Figure 1. Distribution of Polar Bear Populations Throughout the
Circumpolar Basin . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2

---

Polar Bears: Proposed Listing Under the
Endangered Species Act
The proposed listing of polar bears as threatened under the Endangered Species
Act (ESA; 16 U.S.C. §§1531 et seq.) highlights the intersection of two significant
issues currently before Congress — climate change and species protection. This
listing decision rests solely on an interpretation of the best available scientific
understanding of the species and how it may be affected by changing habitat.
Background
The polar bear, Ursus maritimus, is the largest terrestrial carnivore and a top
predator, inhabiting circumpolar Arctic regions wherever sea ice is present for a
substantial part of the year. Nineteen known or identified populations of polar bears
have an estimated total abundance of 20,000 to 25,000 animals (Figure 1). Two of
these populations occur within U.S. jurisdiction — the Southern Beaufort Sea
population (shared about equally with Canada) is estimated at 1,526 animals,1 while
the Chukchi/Bering Seas population (shared with Russia) is estimated at about 2,000
animals.2 Polar bear populations are in decline in Western Hudson Bay and may be
starting to decline in the Southern Beaufort Sea. Simulations suggest that polar bear
populations are also declining in Baffin Bay, Kane Basin, and Norwegian Bay.
Globally, less than one-third of the 19 populations are declining, and more than one-
third are increasing or stable, while the remaining third have insufficient data
available to estimate population trends and their status has not been assessed.3 The
status of the polar bear in the Central Arctic Basin, the largest population, is
unknown. Large carnivorous mammals are generally considered to be most at risk
of population declines and extinctions,4 and the minimum viable total population of
polar bears has been estimated at 4,961 individuals.5
1 E. V. Regehr, S. C. Amstrup, and I. Stirling, Polar Bear Population Status in the Southern
Beaufort Sea, U.S. Geological Survey, Open File Report 1337 (2006).
2 This abundance estimate, by the Polar Bear Specialist Group (see footnote 3), has low
confidence, with no estimate of precision or bias.
3 Polar Bear Specialist Group, Proceedings of the 14th Working Meeting of the IUCN/SSC
Polar Bear Specialist Group, Occasional Paper of the IUCN Species Survival Commission
No. 32 (2006), p. 34-35, available at [http://pbsg.npolar.no/docs/PBSG14proc.pdf].
4 M. Cardillo et al., “Multiple Causes of High Extinction Risk in Large Mammal Species,”
Science, v. 309, no. 5738 (Aug. 19, 2005): 1239-1241.
5 D. H. Reed et al., “Estimates of Minimum Viable Population Sizes for Vertebrates and
Factors Influencing Those Estimates,” Biological Conservation, v. 113, no. 1 (September
2003): 23-34.

---

CRS-2
Figure 1. Distribution of Polar Bear Populations
Throughout the Circumpolar Basin
Source: Polar Bear Specialist Group, Proceedings of the 14th Working Meeting of the
IUCN/SSC Polar Bear Specialist Group, p. 33. SB = Southern Beaufort Sea, NB =
Northern Beaufort Sea, VM = Viscount Melville, NW = Norwegian Bay, LS = Lancaster
Sound, MC = McClintock Channel, GB = Gulf of Boothia, FB = Foxe Basin, WH =
Western Hudson Bay, SH = Southern Hudson Bay, KB = Kane Basin, BB = Baffin Bay,
DS = Davis Strait.
The primary prey of polar bears is the ringed seal — a polar bear may stalk a
seal by waiting quietly for it to emerge from an opening in the ice that seals make to
breathe or climb out of the water to rest. Ringed seals have a circumpolar
distribution and are associated with ice year-round. Much of ringed seal habitat
(especially in offshore drifting sea ice) has not been surveyed, leading to much
uncertainty regarding population size and status. Current estimates of the global
population numbers for ringed seal range from more than 2 million to as many as 7
million animals. Other prey include bearded and harp seals, juvenile walrus, beluga
whales, narwhal, fish, and seabirds and their eggs. Over most of their range, polar
bears remain on the sea ice year-round or spend at most only short periods on land.
In October and November, male polar bears head out onto sea ice where they spend
the winter.

---

CRS-3
Polar bears have one of the lowest reproductive rates of any mammal, with
mature females reproducing once every three years. Pregnant females either seek
sites on the sea ice (“pelagic bears”) or on mainland areas (“nearshore bears”) to dig
large dens in snow where they give birth and spend the winter.6 Females do not
require mainland sites for denning, but some individuals seem to prefer them. Both
pelagic and nearshore individuals are known in all subpopulations studied.7
Currently, polar bears are protected and managed under domestic law and
several international agreements. Because the primary habitat of the polar bear is sea
ice and this species is evolutionarily adapted to life at sea, it is managed as a marine
mammal. In the United States, polar bears are protected under the Marine Mammal
Protection Act (MMPA; 16 U.S.C. §§1361 et seq.), with the Fish and Wildlife
Service (FWS) in the Department of the Interior as the federal management agency.
The Alaska Nanuuq Commission, a Native organization representing villages in
northern and northwestern Alaska, has a co-management agreement with the FWS
to provide input on matters related to the conservation and sustainable use of polar
bears.8
Internationally, the multilateral 1973 Agreement on the Conservation of Polar
Bears9 and the 2000 bilateral Agreement Between the Government of the United
States of America and the Government of the Russian Federation on the
Conservation and Management of the Alaska-Chukotka Polar Bear Population10
provide a basis for cooperation on polar bear management. In addition, Alaska and
Canada exercise joint cross-border management through the Inuvialuit-Inupiat Polar
Bear Management Agreement for the Southern Beaufort Sea.11 The International
Union for the Conservation of Nature (IUCN) classifies the polar bear as vulnerable
on the IUCN Red List of Threatened Species. The IUCN classification of vulnerable
represents a judgment that the species is facing a high risk of extinction in the wild.12
In addition, polar bears are listed on Appendix II of the Convention on
International Trade in Endangered Species of Fauna and Flora (CITES). Appendix
II contains species not necessarily threatened with extinction but requiring controlled
6 U.S. Dept. of the Interior, Fish and Wildlife Service, “Polar Bear Fact Sheet,” available at
[http://www.fws.gov/home/feature/2006/polarbear.pdf], and “Polar Bear Questions and
Answers,” available at [http://www.fws.gov/home/feature/2006/PolarbearFAQ.pdf].
7 Mette Mauritzen, Andrew E. Derocher, and Oystein Wiig, “Space-Use Strategies of
Female Polar Bears in a Dynamic Sea Ice Habitat,” Canadian Journal of Zoology, v. 79
(Sept. 2001): 1704-1713.
8 See [http://www.nanuuq.info/index.html].
9 Parties to this agreement are Canada, Denmark, Norway, the Russian Federation, and the
United States. See [http://sedac.ciesin.org/entri/texts/polar.bears.1973.html].
10 See [http://alaska.fws.gov/media/pbsigning/agreement.html].
11 See [http://pubs.aina.ucalgary.ca/arctic/Arctic55-4-362.pdf].
12 This assessment is based on a suspected population decline of more than 30% within three
generations (45 years) due to decline in area of occupancy, extent of occurrence, and habitat
quality.

---

CRS-4
trade to prevent population declines, as well as other species whose body parts are
difficult to distinguish by visual inspection (the so-called “look-alike” problem, in
this case in controlling trade in bear gall bladders).13 ESA implements CITES
provisions domestically. As such, ESA affords protection to endangered species and
wildlife of global concern. To complement CITES, ESA specifically prohibits
interstate and foreign commerce in ESA-listed species. FWS agents and inspectors
work to control any illegal trade and international movement of CITES- and ESA-
listed species, since some species found in other countries may be brought into the
United States by activities that could threaten their long-term survival. ESA is
applicable to activities within U.S. jurisdiction, as well as activities by U.S. citizens
anywhere, including the high seas.
Circumstances Affecting Polar Bears
Climate Change14
Climate change is widely believed to be one of the most significant
contemporary threats to biodiversity worldwide.15 A May 2002 report by the World
Wildlife Fund raised public concern that polar bears were threatened by climate
change.16 Scientists have confirmed that, in recent decades, the extent of Arctic sea
ice has declined significantly as the result of climate warming: annual ice break-up
in many areas is occurring earlier and freeze-up later, Arctic sea ice is experiencing
a continuing decline that it is thought may not easily be reversed,17 and some models
project that Arctic sea ice could disappear completely by the second half of this
century.18
Distribution patterns of some polar bear populations have changed in recent
years. Greater numbers of bears are being found onshore near the Bering Sea,19 and
13 For additional background on CITES, see CRS Report RL32751, The Convention on
International Trade in Endangered Species of Wild Fauna and Flora (CITES): Background
and Issues, by Pervaze A. Sheikh and M. Lynne Corn.
14 For background on climate change, see CRS Report RL33849, Climate Change: Science
and Policy Implications, by Jane Leggett.
15 C. D. Thomas et al., “Extinction Risk from Climate Change,” Nature, v. 427, no. 6970
(Jan. 8, 2004): 145-148; Arctic Climate Impact Assessment, Impacts of a Warming Arctic:
Arctic Climate Impact Assessment (Cambridge University Press, 2005), 144 p.
16 Stefan Norris, Lynn Rosentrater, and Pal Martin Eid, Polar Bears at Risk (World Wildlife
Fund, May 2002), available at [http://www.ngo.grida.no/wwfap/polarbears/risk/PolarBears
AtRisk.pdf].
17 R. W. Lindsay and J. Zhang, “The Thinning of the Arctic Sea Ice, 1988-2003: Have We
Passed a Tipping Point?” Journal of Climate, v. 18, no. 22 (2005), pp. 4879-4894.
18 Intergovernmental Panel on Climate Change, Climate Change 2007: The Physical Science
Basis, Summary for Policymakers (Geneva, Switzerland: February 2007), 21 pp.
19 S. L. Schliebe, T. Evans, S. Miller, and J. Wilder, “Fall Distribution of Polar Bears along
(continued...)

---

CRS-5
in some parts of Canada,20 with Inuit hunters reporting more bears present on land
during summer and fall.21 There may be several reasons for the observed changes,
including changes in sea ice; those who conduct population censuses of polar bears
will need to be cautious in interpreting whether apparent population variations are
indicative of different habitat use (e.g., greater numbers of bears onshore) or actual
changes in population abundance.
The projected loss of sea ice could affect survival and reproduction of polar
bears by:
! shortening the season during which ice is available to serve as a
platform for hunting seals;22
! increasing the distance between the ice edge and land, thereby
making it more difficult for nearshore female bears that prefer to den
on land to reach preferred denning areas;
! reducing the availability of sea ice dens for gestating pelagic female
bears;
! requiring nearshore bears to travel through fragmented sea ice and
open water, which uses more energy than walking across stable ice
formations;23
! reducing the availability and accessibility of ice-dependent prey,
such as ringed seals, to nearshore populations;24 and
19 (...continued)
Northern Alaska Coastal Areas and Relationship to Pack Ice Position,” in Collection of
Scientific Papers from the 4th International Conference of Marine Mammals of the
Holarctic, V. M. Belkovich, ed. (St. Petersburg, Russia: 2006), p. 559.
20 E. K. Parks, et al., “Seasonal and Annual Movement Patterns of Polar Bears on the Sea
Ice of Hudson Bay,” Canadian Journal of Zoology, v. 84, no. 9 (September 2006): 1281-
1294.
21 Unpublished reports in 2005 by M. Dowsley and M. Taylor, as cited in the FWS polar
bear status assessment report (see footnote 41).
22 For every week earlier the sea ice breaks up, bears come ashore 10 kilograms lighter in
weight, on average. See Ian Stirling and A.E. Derocher, “Possible Impacts of Climatic
Warming on Polar Bears,” Arctic, v. 46 (1993): 240-245.
23 Loss of sea ice forces polar bears to cross large expanses of water and increases risk of
drowning. In 2004, scientists documented polar bears swimming as far as 60 miles offshore
and observed 4 drowned bears. See C. Monnett and J.S. Gleason, “Observation of Mortality
Associated with Extended Open-Water Swimming by Polar Bears in the Alaskan Beaufort
Sea,” Polar Biology, v. 29, no. 8 (July 2006): 681-687.
24 I. Stirling and C. L. Parkinson, “Possible Effects of Climate Warming on Selected
Populations of Polar Bears (Ursus maritimus) in the Canadian Arctic,” Arctic, v. 59, no. 3
(September 2006): 261-275; S. H. Ferguson, I. Stirling, and P. McLoughlin, “Climate
Change and Ringed Seal (Phoca hispida) Recruitment in Western Hudson Bay,” Marine
Mammal Science, v. 21, no. 1 (Janaury 2005): 121-135.

---

CRS-6
! requiring nearshore bears to spend more time on land, thereby
increasing the potential for adverse human-polar bear interactions.25
In addition to changing sea ice conditions, climate change might affect the integrity
of polar bear den sites, as rain can destroy ice dens, exposing young polar bears to the
elements prematurely.26
Although some scientists predict the extinction of polar bears under potential
climate change scenarios, not all sea-ice changes would harm polar bears. For
example, reduced sea ice thickness and coverage in far northern regions is likely to
improve polar bear habitat, by increasing the availability and accessibility of ice-
dependent prey, such as ringed seals.27 Others remind biologists that climate-related
changes to a species’ distribution does not necessarily result in changes in
abundance.28
Contaminants
Three main groups of contaminants are implicated as potentially threatening
polar bears — petroleum hydrocarbons, persistent organic pollutants, and heavy
metals. Polar bears are particularly vulnerable to oil spills, because oil damages polar
bear fur (decreasing the bears’ ability to thermoregulate) and because of oil ingestion
(poisoning) via grooming and/or eating contaminated prey.29 Although elevated
concentrations of some persistent organic pollutants have been discovered in polar
bears, it has been difficult to determine what biological effects these chemicals might
have on polar bears; weakened immune systems and reduced reproductive success
are among the concerns.30 Some persistent organic pollutants are endocrine
disruptors and are thought to cause pseudo-hermaphrodism and aberrant genital
morphology in polar bears.31 Mercury is a particular concern because of its toxicity
at low concentration, and its magnification and accumulation through the food web.
However, polar bears appear able to demethylate (i.e., alter the chemical form and
biological reactivity of) mercury and accumulate somewhat elevated levels of
25 Marine Mammal Commission. Annual Report to Congress, 2005 (Bethesda, MD: July 15,
2006), p. 52.
26 Stefan Norris, Lynn Rosentrater, and Pal Martin Eid, Polar Bears at Risk (World Wildlife
Fund, May 2002).
27 A. E. Derocher, N. J. Lunn, and I. Stirling, “Polar Bears in a Warming Climate,”
Integrative and Comparative Biology, v. 44, no. 2 (April 2004): 163-176.
28 C. J. Krebs and D. Berteaux, “Problems and Pitfalls in Relating Climate Variability to
Population Dynamics,” Climate Research, v. 32 (2006): 143-149.
29 D. J. St. Aubin, “Physiologic and Toxic Effects on Polar Bears,” in Sea Mammals and Oil:
Confronting the Risks, J. R. Geraci and D. J. St. Aubin, eds. (New York, NY: Academic
Press, Inc., 1990), p. 235-239; N. A. Oritsland, et al., Effect of Crude Oil on Polar Bears,
Environmental Studies No. 24, Northern Affairs Program, Northern Environmental
Protection Branch, Indian and Northern Affairs, Canada (1981), 268 pp.
30 J. U. Skarre et al., “Ecological Risk Assessment of Persistent Organic Pollutants in the
Arctic,” Toxicology, v. 181-182 (2002): 193-197.
31 C. M. Fossi and L. Marsili, “Effects of Endocrine Disruptors in Aquatic Mammals,” Pure
and Applied Chemistry, v. 75, nos. 11-12 (Nov.-Dec. 2003): 2235-2247.

---

CRS-7
mercury without harm.32 Climate change may alter contaminant pathways through
increased precipitation, increasing the potential threat to polar bears.33
Subsistence and Sport Harvest
The United States allows limited subsistence harvest of polar bears by Alaska
Natives. Subsistence harvest of depleted, threatened, and endangered marine
mammals can be managed in different ways. Due to concerns for depleted beluga
whales in Cook Inlet, AK, subsistence harvest by Alaska Natives has been severely
restricted (0 to 2 animals annually) since 1999.34 On the other hand, a substantial
Alaska Native subsistence harvest of endangered bowhead whales continues, with 75
whales permitted to be struck in 2006.35 In the year from July 1, 2004, through June
30, 2005, Alaska Natives harvested 27 polar bears from the Southern Beaufort Sea
population and 33 polar bears from the Chukchi/Bering Seas population. In addition,
there is particular concern for the Chukchi/Bering Seas population due to anecdotal
evidence that unregulated harvest by Russian Natives on the Chukotka Peninsula may
be reaching unsustainable levels.36
In Canada, Native hunters are permitted to allocate a limited portion of the
subsistence harvest to sport hunters.37 Under 1994 amendments to the MMPA, U.S.
citizens may obtain permits to import sport-harvested polar bear trophies from
Canada, taken under scientifically sound quotas ensuring the maintenance of the
affected population at a sustainable level.38 In 2006, FWS issued 72 permits for
importing polar bear trophies from Canada, with more than half taken from the
Lancaster Sound population.
Habitat damage from climate change may interact with subsistence and sport
harvest to increase polar bear mortality. For example, large adult male bears, more
likely to be targeted by hunters, may also be more at risk from the effect of climate
change on prey availability since larger bears require greater amounts of food. In
addition, male bears also disperse greater distances than females and thus could be
more affected by the necessity to swim increasing distances.
32 Arctic Monitoring and Assessment Programme, AMAP Assessment 2002: Persistent
Organic Pollutants in the Arctic (Oslo, Norway: 2005), p. 123.
33 R. W. Macdonald, T. Harner, and J. Fyfe, “Recent Climate Change in the Arctic and Its
Impact on Contaminant Pathways and Interpretation of Temporal Trend Data: Review
Article,” Science of The Total Environment, v. 342, no. 1-3 (Apr. 1, 2005): 5-86.
34 71 Fed. Reg. 15697-15698 (Mar. 29, 2006).
35 71 Fed. Reg. 7539 (Feb. 13, 2006).
36 Marine Mammal Commission. Annual Report to Congress, 2005 (Bethesda, MD: July 15,
2006), p. 50-51.
37 M. M. R. Freeman and G. W. Wenzel, “The Nature and Significance of Polar Bear
Conservation Hunting in the Canadian Arctic,” Arctic, v. 59, no. 1 (2006): 21-30.
38 P.L. 103-238, §§4, 5; 16 U.S.C. §1371(a)(1); 16 U.S.C. §1374(c)(5).

---

CRS-8
Protection Efforts
On February 17, 2005, FWS received a petition from the Center for Biological
Diversity requesting that FWS list the polar bear as threatened under ESA throughout
its range and that it designate critical habitat for this species.39 The Natural
Resources Defense Council and Greenpeace, Inc., joined as petitioners on July 5,
2005. On December 15, 2005, the petitioners filed a complaint, challenging FWS’s
failure to issue a 90-day finding on the petition. On February 7, 2006, FWS
announced a finding that the petition presented substantial scientific information
indicating that listing the polar bear might be warranted, and subsequently announced
the initiation of a formal status review.40
In a settlement agreement, approved on July 5, 2006, FWS agreed to submit a
12-month finding on the petition by December 27, 2006. On January 9, 2007, FWS
announced its 12-month finding on the petition — concluding that, after a review of
scientific and commercial information, listing the polar bear as a threatened species
under ESA was warranted — and formally proposed such listing.41 This proposed
rule does not designate critical habitat for the polar bear. A 90-day period (through
April 9, 2007) was announced to receive data and comments, with requests for a
public hearing accepted for 45 days (through February 23, 2007). A decision on
whether to list polar bears is due from FWS in January 2008.
The Secretary of the Interior must decide whether to list polar bears under ESA
based only on the best available scientific and commercial (i.e., trade) information,42
after an extensive series of procedural steps to ensure public participation and the
collection of relevant information. The listing decision considers information
relating to five factors: habitat destruction, overutilization, disease or predation,
inadequacy of other regulatory mechanisms, and other natural or manmade factors.43
At this point in the ESA process, the Secretary may not consider the economic effects
that listing may have. The listing determination is the only place in ESA where
39 A species may be designated as either endangered or threatened, depending on the severity
of its decline and threats to its continued survival. The prohibitions and penalties of ESA
apply primarily to those species listed as endangered. Under § 4(d) of ESA, the Secretary
may promulgate special regulations to address the plight of species listed as threatened.
Protections and recovery measures for a particular threatened species can be tailored to
particular situations. 50 C.F.R. §17.31 also affords threatened species for which a special
rule has not been promulgated the same protections as endangered species. For additional
background on ESA as well as regulatory procedures under this act, see CRS Report
RL31654, The Endangered Species Act: A Primer, by M. Lynne Corn, Eugene H. Buck, and
Pamela Baldwin.
40 71 Fed. Reg. 6745 (Feb. 9, 2006). Information on the status of the polar bear was solicited
from the public in this notice and again in 71 Fed. Reg. 28653 (May 17, 2006).
41 72 Fed. Reg. 1064-1099 (Jan. 9, 2007). The polar bear status assessment document is
available at [http://alaska.fws.gov/fisheries/mmm/polarbear/pdf/Polar_Bear_%20Status_
Assessment.pdf].
42 16 U.S.C. §1533(b)(1)(A).
43 16 U.S.C. §1533(a)(1).

---

CRS-9
economic considerations are expressly forbidden; such considerations may enter in
other stages, including critical habitat designation.
Economic factors cannot be taken into account at this stage because Congress
directed that ESA listing be fundamentally a scientific question: is the continued
existence of the species threatened or endangered? If polar bears were listed under
ESA, federal agencies would be required to ensure that anything the federal
government authorized, funded, or carried out that is likely to affect polar bears or
their habitat would not jeopardize the survival of these bears or destroy or adversely
modify their habitat.
The Committee on the Status of Endangered Wildlife in Canada (COSEWIC)
is also reviewing the status of the polar bear in Canada. In addition, many would cite
the multilateral 1973 Agreement on the Conservation of Polar Bears as a significant
and substantive protection effort that provides international oversight of various
national research and management programs.44
Controversy
Supporters of increased protection for polar bears argue that polar bears are the
most iconic Arctic species, representing the Arctic as lions represent Africa. They
further assert that it would be irresponsible to let the polar bear become extinct as a
result of human action, and would be a terrible blow to the psyche of humankind.
However, some critics suggest that the current proposal to list polar bears as
threatened is premature, with this species being used as a “poster child” for the evils
of climate change by the popular press in recognition of polar bears’ charismatic
appeal; some believe the less-glamorous walrus could be facing similar or greater
immediate risk.
Some scientists also point out that, since polar bears have survived at least two
major warming periods over the last 10,000 years, including the intense warming
event that ended the Last Glacial Maximum about 8,000 to 9,000 years ago (when
temperatures were believed to have been much warmer than now), polar bears and
other Arctic mammals could be capable of adjusting, adapting, and coping with the
current climatic change. At the end of the last Ice Age, the Northern Hemisphere
entered an extended period of rapid warming, with temperatures in Arctic regions
eventually reaching levels several degrees warmer than today. At that time, the sea
ice above North America is known to have retreated substantially, allowing Arctic
species such as bowhead whales and walrus to move northward into areas of the
Canadian Arctic that they cannot reach today. The Mid-Holocene Warm Period
peaked about 11,000-9,000 years ago near Alaska and about 8,000-5,000 years ago
near Greenland and Northern Europe. In both areas, temperatures rose rapidly 10-15
degrees Centigrade to a point significantly warmer than present (about 2.5 degrees
Centigrade warmer; but less than the temperatures projected by the
44 P. Prestrud and I. Stirling, “The International Polar Bear Agreement and the Current
Status of Polar Bear Conservation,” Aquatic Mammals, v. 20, no. 3 (1994): 113-124.

---

CRS-10
Intergovernmental Panel on Climate Change for 2100), and about 5-10 degrees
Centigrade of that warming took place within 30 years or less.45
Another significant but shorter warm period occurred about 1,000 years ago,
when Arctic temperatures were slightly warmer than today. This warming also
triggered sea ice reductions in Arctic regions and was accompanied by significant
reductions in Greenland glaciers, creating so much arable land that Viking settlers
established farms on the west coast of Greenland that were occupied for about 400
years.46
There is no evidence to suggest that ice in the Arctic Basin disappeared entirely
during either of these warm periods or that any ice-dependent species became extinct.
Polar bears and their primary prey existed before the last Ice Age and significant
populations of them remain today. The tight association of polar bears and their prey
species with moving sea ice gives them a flexibility that land-based carnivores do not
have.
Others counter that polar bears today are not coping with changing climate
alone, but also face a host of other human-induced factors — including shipping, oil
and gas exploration, contaminants, and reduced prey populations — that compound
the threat to their continued existence.47 In addition, the opportunity for a
catastrophic disease event is greater in populations subject to multiple stressors.
Furthermore, they emphasize that current climate warming may be occurring at an
accelerated rate, due to human influence, compared to past periods of climate
warming, and species may be less capable of adapting to these more rapid changes.
Others suggest that there is considerable uncertainty in the estimates of polar
bear population numbers and trends as well as in our understanding of polar bear
habitat. Much of what we know about the polar bear habitat is confined to regions
close to shore that have been studied during long summer days, with little known
about what happens on drifting sea ice far from shore, especially in winter when there
is little or no daylight. These critics also urge caution on interpreting studies of sea
ice change that are based primarily on surveys of nearshore regions, rather than the
drifting sea ice environment in the central Arctic Basin, where ice may be thickest.
Recent studies conclude there is significantly more variability in ice thickness
45 D. S. Kaufman et al., “Holocene Thermal Maximum in the Western Arctic (0-180 Degrees
W,” Quaternary Science Reviews, v. 23, nos. 18-19 (October 2004): 2059-2060; Arthur S.
Dyke, et al., “The Late Wisconsinan and Holocene Record of Walrus (Odobenus rosmarus)
from North America: A Review with New Data from Arctic and Atlantic Canada,” Arctic,
v. 52, no. 2 (June 1999): 160-181; Arthur S. Dyke and James M. Savelle, “Holocene History
of the Bering Sea Bowhead Whale (Balaena mysticetus) in its Beaufort Sea Summer
Grounds off Southwestern Victoria Island, Western Canadian Arctic,” Quaternary
Research, v. 55 (2001): 371-379.
46 Willie Soon and Sallie Baliunas, “Proxy Climatic and Environmental Changes of the Past
1000 Years,” Climate Research, v. 23 (Jan. 31, 2003): 89-110.
47 A. Shi, A. M. Bell, and J. L. Kerby, “Two Stressors are Far Deadlier Than One,” Trends
in Ecology and Evolution, v. 19 (2004): 274-276.

---

CRS-11
between years and regions than is predicted by climate models, which means that ice
thickness can increase or decrease rapidly as well as differ among regions.48
Under ESA, the Secretary is required to take into account foreign polar bear
conservation programs, including conservation hunting programs involving non-local
(including U.S.) hunters. However, an ESA listing as “threatened” triggers an
automatic listing as “depleted” under the MMPA, a listing that would prevent U.S.
citizens from importing polar bear products into the United States. Such an import
ban, effectively stopping U.S. participation in conservation hunting programs, is
likely to seriously compromise successful Canadian community-based conservation
programs.49
48 Seymour Laxon, Neil Peacock, and Doug Smith, “High Interannual Variability of Sea Ice
Thickness in the Arctic Region,” Nature, v. 425 (Oct. 30, 2003): 947-950.
49 M. M. R. Freeman and G. W. Wenzel, “The Nature and Significance of Polar Bear
Conservation Hunting in the Canadian Arctic,” Arctic, v. 59, no. 1 (2006): 21-30.

---