The Bush administration on Wednesday designated the polar bear as threatened with extinction, making the big arctic bear, whose fate clings to shrinking sea ice, the first creature added to the endangered species list primarily because of global warming.




The designation invokes federal protections under the Endangered Species Act, the Unites States' most powerful environmental law that requires designation of critical habitat to be protected as well as forming a strategy to assist the bear population's recovery.




The decision came only after a U.S. District Court in Oakland, Calif., forced the Bush administration's hand by imposing a May 15 deadline for the decision that was supposed to have been completed by Jan. 9.




It was the first time in more than two years that the Interior Department extended protections to another species under the Endangered Species Act &

the longest hiatus of new listings by the department since President Nixon signed the law in 1973.




Pressure has been mounting from inside and outside the government. Various congressional committees have held hearings to nudge the administration to protect the bear and complained about delays on the decision. Meanwhile, the government marched ahead on Feb. 6 to open offshore oil fields to exploratory drilling in prime polar bear habitat.




The court's deadline evolved from a lawsuit seeking a court order to force the U.S. Fish and Wildlife Service to comply with the legal deadline for the decision and another suit challenging the offshore leases. And then the Interior Department's inspector general opened an investigation into allegations that the decision had been detained by "inappropriate political influence."




The yearlong clock began ticking when Interior Secretary Dirk Kempthorne on Dec. 27, 2006, announced that there was sufficient scientific evidence of the bear's melting habitat to officially propose that the polar bear join the list of species threatened with extinction.




The proposal did not include designating critical habitat. Nor did it include a scientific analysis of the causes of climate change, which Kempthorne said was beyond the scope of scientific review under the Endangered Species Act. He directed the U.S. Fish and Wildlife Service to work with the public and the scientific community to broaden understanding of what is happening to the species.




Since then, the arctic sea ice last summer retreated to record levels &

a retreat that about half of the climate modelers did not think would happen until 2050.




In September, scientists at the U.S. Geological Survey released a comprehensive nine-volume analysis of the science and reached a dire forecast: Two-thirds of the bear's habitat would disappear by 2050.




Polar bears are experts at hunting ringed seals and other prey on sea ice. But they are so unsuccessful on land, they spend their summers fasting, losing more than 2 pounds a day.




This forced fast is an average of three weeks longer than it was 30 years ago, according to studies in Canada's western Hudson Bay. This gives the bears less time to hunt and build up fat reserves they need to make it until they can resume hunting with reformation of the ice in the fall.




As bears have become thinner, the reproductive rates of female bears has declined. The survival rates of cubs have fallen, too. Overall, the western Hudson Bay population has dropped by 22 percent since 1987.




These bears in the Hudson Bay are among the best studied populations. Scientists don't know if similar trends exist elsewhere in the arctic, which is a vast and forbidding place to conduct field work. Surveys have shown other problems, including bears swimming and drowning in open waters left by ever-increasing gaps in the sea ice and cannibalism among hungry bears.




Overall, scientists believe the global population of 20,000 to 25,000 bears remains robust. But virtually all polar bear experts predict rapid population declines in the Arctic, which is warming faster than anywhere else in the world, and changing too rapidly for the bears to adapt.




A group of Canadian scientists last month declared the polar bear as a "species of concern," but stopped short of saying it was "threatened" with extinction &

a designation that could have restricted hunting by Canada's Inuit people.




Canada has about two-thirds of the world's polar bear population. Interior Secretary Kempthorne joined Canada's environmental minister last week to sign an agreement that the two governments would form an intergovernmental group with tribal government to consider "the best available scientific information and aboriginal traditional knowledge."




The Nunavut Wildlife Management Board, which operates in Canada's far north, recently proposed reducing the quota of polar bears hunted in Baffin Bay, a proposal opposed by Inuit trappers and hunters saying their traditional knowledge reveals there are too many bears in the area.