Polar bear population seen declining

Two-thirds of the world’s polar bears will be killed off by 2050 — and the entire population gone from Alaska — because of thinning sea ice from global warming in the Arctic, government scientists forecast Sept. 7.

Only in the northern Canadian Arctic islands and the west coast of Greenland are any of the world’s 16,000 polar bears expected to survive through the end of the century, said the U.S. Geological Survey, which is the scientific arm of the Interior Department. USGS projects that polar bears during the next half-century will disappear along the north coasts of Alaska and Russia and lose 42 percent of the Arctic range they need to live in during summer in the Polar Basin when they hunt and breed.

“Projected changes in future sea ice conditions, if realized, will result in loss of approximately two-thirds of the world’s current polar bear population by the mid 21st century,” the report says.

Polar bears depend on sea ice as a platform for hunting seals, which is their primary food. They rarely catch seals on land or in open water.

“There is a definite link between changes in the sea ice and the welfare of polar bears,” said USGS scientist Steven Amstrup, the lead author of the new studies. He said 84 percent of the scientific variables affecting the polar bear’s fate was tied to changes in sea ice.

“In spite of any mitigation of greenhouse gases, we are going to see the same amount of energy in the system for at least 20, 30, 40 years,” Mark Myers, the USGS director, said.

Greenland and Norway have the most polar bears, while a quarter of them live mainly in Alaska and travel to Canada and Russia. The agency says their range will shrink to no longer include Alaska and other southern regions.

The findings of U.S. and Canadian scientists are based on six months of new studies, during which the health of three polar bear groups and their dependency on Arctic sea ice were examined using “new and traditional models,” Myers said.

USGS analysis was done to guide Interior Secretary Dirk Kempthorne’s decision expected in January on his agency’s proposal to add the polar bear to the government’s endangered species list.

Last December, Kempthorne proposed designating polar bears as a “threatened” species deserving of federal protection under the Endangered Species Act. That category is second to “endangered” on the government’s list of species believed most likely to become extinct.

—The Associated Press