A federal judge will hear arguments next week in a case that speaks to a central question regarding Arctic animals affected by climate warming: When is a species endangered?
Polar bears were declared a "threatened" species in 2008 because of the rapid loss of the Arctic sea ice that they use for fattening up on seals, which carries them through long periods of not eating. The federal government argues that's the correct call.
Environmental groups that pushed for the listing say all evidence indicates polar bears should be declared "endangered" because two-thirds of the world's current polar bear populations could disappear by mid-century because of warming brought on by greenhouse gases.
The state of Alaska bitterly opposes any listing and the additional protections they provide, claiming polar bears are plentiful, predicting future sea ice is unreliable, and federal wildlife authorities are looking too far into the future.
Combined lawsuits before Judge Emmet Sullivan of the U.S. District Court in Washington, D.C., look at what Congress intended when it passed the Endangered Species Act. The decision will affect management of other ice-dependent marine mammals off Alaska's coast, including walrus and four kinds of ice seals.
Sullivan heard from the parties in October and a month later said the Interior Department had inadequately explained why polar bears were listed as threatened rather than endangered.
He rejected the federal government's contention that a species must be in imminent danger of extinction to be declared endangered. Such an "imminence" requirement was an erroneous conclusion, he wrote, and lawmakers intentionally left the law ambiguous to give regulators flexibility to respond to variable conditions.
The law says a listing determination must be made on one or more of five factors. The first listed, and most relevant for polar bears, is the current or threatened destruction of habitat.
Arctic marine species are notoriously difficult to count but one number in hand in the debate is the satellite measurement of sea ice where polar bears live.
According to the National Snow and Ice Data Center at the University of Colorado, the summer low for sea ice, measured each September, averaged 2.7 million square miles from 1979 to 2000. Sea ice in recent years has fallen far below that, including a record low 1.65 million square miles in summer 2007.
The low last summer was 1.84 million square miles. That means an area the size of Texas, California, Montana, New Mexico and Arizona combined, much of it over the rich waters of the continental shelf, was unavailable for much of 2010.
Alaska officials see endangered species listings as an impediment to offshore petroleum drilling, the main hope of keeping oil in the trans-Alaska pipeline as onshore sources of oil dry up. Petroleum provides upward of 90 percent of general fund revenue to state coffers.
Gov. Sean Parnell in his 2010 State of the State address said the federal government has misused the Endangered Species Act as a regulatory weapon to delay development of Alaska's resources. He made the law a target again this year, calling proposed critical habitat designations "job killers."
"We aggressively fight unwarranted listings and habitat designations," Parnell said. "These federal actions threaten Alaskans' jobs and our economic potential, and the federal government must reconsider them."
Commenting this month on the proposal to list walrus, Parnell's endangered species coordinator, Doug Vincent-Lang, acknowledged that the animal's habitat may change over the next 25 to 50 years but said information about their life history and previous experience with warming climates suggested that walrus would be able to adapt.
"While the walrus population may decline in response to a smaller carrying capacity, the resultant population will not be threatened with extinction within the next 25-50 years and therefore the decision that listing is warranted is unnecessary at this time."
Kassie Siegel, the attorney for the Center for Biological Diversity who wrote the original polar bear listing petition, said the ESA was written as a safety net to protect species, and the state's interpretation is flawed legally and practically.
"Their interpretation, basically, wouldn't allow protecting something until it was proved that it was going to become extinct, which is contrary to the whole safety net concept," she said.
The law says a species is endangered if it's in danger of extinction throughout all or a portion of its range. A species is threatened if it's likely to become an endangered species in the foreseeable future. Congress specifically put in the "threatened" category so that a species could be protected while there was still time to do something about it, she said
She will argue before Sullivan that polar bears already are endangered.
The polar bear specialist group of the International Union for Conservation of Nature lists eight of the world's 19 subpopulations of polar bears as "declining," including both of Alaska's. Seven other subpopulations are listed as "data deficient" for making the call.
A U.S. Geological Survey pre-listing model for 2020 through 2029 suggested a better than 50 percent chance that polar bears will be extinct in Alaska's Beaufort and Chukchi seas under the minimum sea ice model run. The USGS itself noted that the observed trajectory of Arctic sea ice decline appeared to be underestimated and its assessment of future polar bear status may have been conservative.
Arctic sea ice extent last month covered 5.23 million square miles, the lowest January ice extent recorded since satellite records began in 1979.
"It's this myth of stability," Siegel said. "People keep saying polar bear populations are OK today. It's just not true."