RL33941 - Polar Bears:Listing Under the Endangered Species Act
4-Mar-2009; Eugene H. Buck, M. Lynn Corn, Kristina Alexander; 24 p.
Update: Previous releases:
February 20, 2009
September 2, 2008
June 2, 2008
February 15, 2008
October 9, 2007
May 14, 2007
March 30, 2007
Abstract: On May 14, 2008, Interior Secretary Dirk Kempthorne announced the listing of polar bears as threatened under the Endangered Species Act (ESA). The controversial decision highlights the intersection of two significant issues currently before Congress — climate change and species protection. Under the ESA, a listing decision must rest solely on the best available scientific information concerning the species. Habitat loss has been a major reason for many decisions to add species to the list — in this case, loss of Arctic sea ice. The listing itself was praised by some environmentalists, who nonetheless deplored interim protective regulations for the polar bear as being too weak. Other parties, who opposed the listing itself, argued that the science supporting listing was weak, but felt that the regulations mitigated some of the economic impacts of the listing.
Polar bears depend on Arctic sea ice, which most scientists acknowledge will be affected by climate change causing, at minimum, an earlier annual or seasonal thaw and a later freeze of coastal sea ice. Scientists generally agree that in recent decades, the observed 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. Globally, less than one-third of the 19 known or recognized polar bear populations are declining, more than one-third are increasing or stable. For the remaining one-third there is insufficient data to estimate population trends. Two polar bear populations occur within U.S. jurisdiction. There is considerable uncertainty in estimates of polar bear population numbers and trends as well as in our understanding of polar bear habitat.
Polar bears are affected by climate change, environmental contaminants, and subsistence and sport hunting. Arctic sea ice is experiencing a continuing decline that may not be reversed easily, and some models project that late summer (September) sea ice could even disappear completely by mid-century. 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 oil and gas exploration, shipping, contaminants, and reduced prey populations — that compound the threat to their continued existence. Three main groups of contaminants threaten polar bears — petroleum hydrocarbons, persistent organic pollutants, and heavy metals. The United States has allowed 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 Marine Mammal Protection Act (MMPA), U.S. citizens may obtain permits to import sportharvested polar bear trophies from Canada. However, with ESA listing, polar bear populations are defined as depleted under MMPA, and therefore entry of these trophies is prohibited by MMPA.