The U.S. government today proposed listing polar bears as threatened with extinction under the Endangered Species Act because the animals' sea ice habitat is melting.
"Polar bears are one of nature's ultimate survivors," Department of the Interior Secretary Dirk Kempthorne told reporters today at a press conference.
"They are able to live and thrive in one of the world's harshest environments. But there's concern that their habitat may literally be melting."
The Endangered Species Act requires federal agencies to ensure that all activities the government approves will not harm listed species or their habitats.
Environmental groups quickly connected the announcement with scientific evidence that climate change is melting the iconic bear's Arctic habitat, causing the animals to go hungry and give birth less often.
"This is a watershed decision," said Kassie Siegel, an attorney for the Center for Biological Diversity in Joshua Tree, California. "Even the Bush Administration can no longer deny the science of global warming."
The center was one of three organizations that filed suit against the administration to protect the bear from the impacts of global warming in the Arctic.
Today's announcement meets a deadline under a settlement with the environmental groups to consider adding the bears to the endangered species list.
The proposed listing was published today in the Federal Register. Public comments will be accepted for 90 days, and a final listing decision is expected within a year.
Regulating Emissions?
A formal listing of polar bears as a threatened species would raise the possibility that the U.S. government will force curbs on greenhouse gas emissions, Siegel says.
Polar bears live only in the Arctic, the northernmost region of Earth. The bears swim between ice floes to hunt their primary prey, the ringed seal. They also travel, mate, and sometimes give birth on the ice. Scientists estimate that between 20,000 and 25,000 polar bears live in 19 distinct populations scattered throughout the Arctic.
About 4,700 live in Alaska and spend part of the year in Canada and Russia. Other bear populations are found in Greenland and Norway.
The most studied population resides in western Canada's Hudson Bay. The population there has declined 22 percent due to weight loss and low cub survival stemming from sea ice loss since 1987.
While the Alaska population has not experienced such a steep decline, biologists are concerned that the bears' numbers may drop in the future, as the population faces similar challenges.
Scientists have linked emissions of carbon dioxide and other greenhouse gases to warmer temperatures that are rapidly melting glaciers and polar ice caps.
Earlier this month, for instance, a study based on computer models predicted the Arctic could have a completely ice-free summer by 2040, decades earlier than previously expected.
Scientists say reduced greenhouse gas emissions could slow and maybe even reverse the Arctic ice retreat, allowing polar bears to recover.
The U.S. Fish and Wildlife Service (FWS), the agency responsible for the Endangered Species Act, has ruled out oil and gas development and subsistence hunting as factors in the polar bear decline.
"This is directly tied to the sea ice loss and the ultimate dependence of the polar bear on drift ice," Dale Hall, the FWS director, said in today's teleconference.
But Interior Secretary Kempthorne said his department's scientists lack the authority to address the causes of the receding sea ice and therefore stopped short of blaming ice loss on global warming.
Causation, he said, is beyond the scope of the department's responsibility under the endangered species law.
"However, climate change science initiatives of causation are discussed in other analyses undertaken by the [Bush] Administration," he said. "The administration treats climate change very seriously and recognizes the role of greenhouse gases in climate change."
According to Siegel, of the Center for Biological Diversity, a formal listing could affect the federal approval process for facilities such as industrial coal-fired power plants and lead to stricter fuel economy standards for automobiles.
"Federal agencies will have to ensure that their greenhouse gas emissions do not adversely modify the critical habitat of polar bears or the continued existence of polar bears," she said.
References: National Geographic by John Roach
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