ANCHORAGE - Interior Secretary Dirk Kempthorne hasn't added a U.S. creature to the endangered species list since he took office two years ago. The former Idaho governor has until Thursday to decide on one that could prove troublesome to promising petroleum drilling off Alaska's northern coast and force federal agencies in other states to react to new greenhouse gas emissions.
A federal court in Oakland, Calif., two weeks ago ordered Kempthorne to decide whether to list polar bears as threatened because of global warming's effect on their habitat, the frozen Arctic Ocean.
Polar bears use sea ice for hunting seals, denning and mating. They rely on ice to reach denning areas on shore.
Summer sea ice last year melted to record low levels, receding far beyond the shallow, nutrient-rich outer continental shelf that supports their main prey, the ringed seal. Polar bears that ride the ice spent more time over less productive, deeper water and faced increased distances from the ice edge to shore if the chose to swim late in the year.
Conservation groups fear continued sea ice loss could reduce fat on polar bears, lower their reproduction rates and cause them to expend more energy - all precursors to a population crash.
Habitat loss, projected by most climate models to accelerate, was a basis for the Endangered Species Act listing petition submitted by the Center for Biological Diversity and two other conservation groups.
"Polar bears are completely dependent on Arctic sea ice for all of their essential behavior," said Kassie Siegel, the primary author of the petition.
A recovery plan for polar bears could interrupt plans for petroleum exploration and drilling off Alaska's shore.
Also, conservation groups frustrated by the Bush administration's failure to treat greenhouse gases as a pollutant want a listing to force the federal government to curb emissions, the primary cause of Arctic warming and sea ice loss.
"Greenhouse gases aren't fundamentally different from pesticides or anything else that poisons our land, air or water to such a degree that it harms plants and animals," Siegel said.
The law protects listed species with two primary mechanisms, Siegel said.
Section 7 directs all federal agencies to consult with the management agency, in this case Fish and Wildlife Service, to make sure that actions the agencies authorize, pay for or carry out - such as permits for a power plant - are not likely to jeopardize the animal or result in destruction of its habitat.
Section 9 applies to anyone from individuals to corporations and prohibits them from the "taking" of an endangered species, a protection routinely extended to threatened species. Courts, Siegel said, have routinely interpreted harm to include significant habitat degradation that impairs essential behavior patterns, including breeding or feeding.
The potential threat to petroleum development has Alaska Gov. Sarah Palin and the state's congressional delegation fighting a listing.
Pacific Legal Foundation, a public interest law firm that advocates for limited government, has said it likely will sue if polar bears, already among the most protected species, are listed. Polar bears are at their highest numbers in recorded history and the ESA does not allow the listing of a thriving species, said principal attorney Reed Hopper. The proposal relies on speculative computer models of sea ice flow, he said.
"That does not constitute reliance on best available science," he said. He also questions whether curbing emissions in the United State would have an effect.
"I wouldn't expect a listing to reverse global warming," Hopper said. "It's a global problem."
Siegel said polar bear populations rebounded after an international treaty limited hunting in 1973, but an international polar bear specialist group lists five bear populations as decreasing, two as increasing, five as stable and six as "data deficient."
"Even if it were correct, it's like saying if a baby is born on the Titanic, the passengers on board can't be threatened because the population is increasing," she said. "It's not relevant to the question at hand, which is what's going to happen to polar bears in the future?"
Arctic marine mammals, thriving in some of the world's harshest conditions, are notoriously difficult to count. No population estimate is available for the Chukchi Sea population shared with Russia but USGS scientists found troubling signs in the Beaufort Sea population.
A 2006 study found far fewer polar bears cubs were surviving into their second year between 1990 and 2006 compared to 1967 to 1989. Spring-born cubs counted again in the fall declined from a mean of 61 cubs per 100 females to 25 cubs per 100 females.
The same study found that adult males weighed less and had smaller skulls than those captured and measured two decades before. Researcher Steven Amstrup said the trends were consistent with changes in nutritional status that likely were associated with declines in sea ice.
USGS researchers also took note of anecdotal evidence of bear deaths likely related to sea ice retreat or changes in food availability associated with sea ice retreat - the carcasses of four drowned bears found in fall 2004; evidence three polar bears killing and eating other polar bears; and at least three bears in spring 2006 found dead of starvation.
Siegel said a crash is only a matter of time.
"The ice is melting faster than forecast," she said. "Polar bears can't survive without their habitat and their habitat is disappearing before our eyes."