Do polar bears, which have become the poster child for the potential ravages of future global warming, need special protection from Uncle Sam now?
That's the question under consideration at the US Fish and Wildlife Service, which is poised to recommend whether the icon of the Arctic should be officially designated as a threatened species – even though the bear's numbers currently are not in precipitous decline.
The judiciousness of protecting the polar bear under the Endangered Species Act (ESA), in anticipation that its frozen habitat will be thawing as a consequence of climate change, is a matter of hot debate. Many scientists say Arctic wildlife is experiencing the repercussions of a warming planet more rapidly than organisms in other regions, but others say listing the bear would cause economic hardship and do next to nothing to save its habitat.
"This is a complex issue because we have most polar bear populations not showing significant declines at the moment, but we have a lot of climate models and data showing great losses in the foreseeable future," says Chris Tollefson of the Fish and Wildlife Service (FWS), the federal agency responsible for protecting wildlife and their habitats. The service's recommendation is due by Jan. 9.
If listed, the polar bear would be the first mammal listed as threatened as a consequence of global warming, and the federal government would be required to take action to protect it in Alaska, the only place in the US the bear lives, and in places the US issues permits. The ESA defines a threatened species as one likely to become endangered in the foreseeable future.
With as many as 25,000 wild polar bears dispersed across five countries, the species is not exactly teetering on the edge of oblivion, say opponents of the effort. The World Conservation Union (IUCN), though, reports that five of the Arctic's 19 polar bear populations are already experiencing declines, as the bears lose habitat and food because of melting sea ice.
Bear populations that are currently stable will also face sink or swim conditions in the future if temperatures rise as projected, say researchers. The United States Geological Survey predicts that habitat loss, primarily from global warming, will slash the world's polar bear population to one-third of its current level by mid-century.
"When we look at the current and projected condition of transit sea ice, it is clear that the species as a whole is facing an increasingly formidable habitat," says Andrew Derocher, a biologist at the University of Alberta in Canada and chairman of the IUCN's Polar Bear Specialist Group.
Polar bears rely on frozen sea ice to hunt, find mates, and make dens for rearing their young, and have been known to migrate across areas the size of Montana. Loss of sea ice and changes in its distribution are believed to be causing some bears to compete for habitat and even to eat other bears to survive. The problem has been pronounced in the west Hudson Bay of Canada, where polar bear numbers have dropped by about 25 percent since the 1980s, partly due to a lack of adequate habitat for dens, researchers say.
Alaska Gov. Sarah Palin (R) has publicly opposed the ESA listing. Such a move could cause economic hardship through federal restrictions on development and oil industry projects – all without increasing the polar bear's numbers, argues the Palin administration.
"We know listing polar bears as endangered or threatened will not … cause sea water to freeze," Governor Palin wrote to Interior Secretary Dirk Kempthorne in 2006, as conservation groups petitioned the FWS to research the need to list the bear. Mr. Kempthorne will approve or deny the FWS recommendation.
Even within the Alaska Department of Fish and Game, where global warming is considered a threat to the state, many regard the reasoning behind preemptively listing the polar bear as flimsy.
"There is currently a healthy population of polar bears worldwide," says Ken Taylor, the department's deputy commissioner. "We are concerned that if they use climate modeling to project 45 years ahead, we might be getting too subjective scientifically."
Some conservationists are not optimistic about the polar bear's chances of making the list.
"The Bush administration always manages to surprise us by ignoring the science at the expense of the environment," says Brendan Cummings, attorney with the nonprofit Center for Biological Diversity (CBD) based in Tucson, Ariz., which petitioned to have the bear listed.
Dr. Derocher at the University of Alberta, who has seen the loss of Arctic habitat firsthand during his 25 years studying polar bears, argues that the science is solid and that it's time for governments to protect species made vulnerable by climate change.
"For some people, the proof of this won't be reliable until the last polar bear drowns," he says.
Conservationists expect that many species of plants and animals will be listed under the ESA in coming years. Federal marine mammal scientists are currently studying the viability of Pacific walrus populations in Alaska, and the CBD petitioned late in December to list the ribbon seal as threatened. Two coral species, the elkhorn and staghorn, were listed as threatened last year due to global-warming-induced habitat degradation.