Warming to take heavy toll on polar bears, report says

SEATTLE -- As the pack ice that is the bedrock of their existence melts because of global warming, polar bears are facing unprecedented environmental stress that will cause their numbers to plummet, according to a report by several of the world's leading specialists on the species.

In a closed meeting late last month in Seattle, 40 members of the polar bear specialist group of the World Conservation Union concluded that the animals -- the world's largest bears -- should now be classified as a ''vulnerable" species.

Their conclusion, they said, was based on what they said was a likely 30 percent decline in their worldwide population over the next 35 to 50 years. There are now 20,000 to 25,000 polar bears across the Arctic, which is the polar bears' main habitat.

''The principal cause of this decline is climatic warming and its consequent negative effects on the sea ice habitat of polar bears," according to a statement released after the meeting. Scientists from five countries, including the United States, attended the meeting.

''All the evidence is heading in the same direction, and the trend is dramatic," said Scott Schliebe, who led the Seattle meeting and is polar bear project leader in Alaska for the US Fish and Wildlife Service. ''In a shrinking ice environment, the ability of the bears to find food, to reproduce, and to survive will all be reduced."

Schliebe emphasized that he was speaking for the panel and not for the US government.

The panel's conclusions became public this week as President Bush traveled to the Group of Eight meeting in Scotland, where US officials have lobbied to prevent any specific targets for reducing so-called greenhouse gases from being included in the meeting's final communique. Those gases are widely believed to cause the warming that causes polar icecaps to melt.

The United States is the only G-8 member that has refused to ratify the Kyoto Protocol, which calls for reducing emissions that many scientists say are causing Earth to warm up.

The best longitudinal information on the effect of global warming on polar bears comes perhaps from the western coast of Hudson Bay, in Manitoba. It found a 17 percent decline in the bears' population in the past 10 years, from 1,200 to fewer than 1,000. The panel in Seattle used the Canadian research as a basis for its warning about the future of polar bears around the world.

''We have seen with our own eyes that climatic warming is causing the ice to break up earlier," said Ian Stirling, a scientist for the Canadian Wildlife Service.

Ice is melting there about three weeks earlier than it did 30 years ago, Stirling said. ''For a polar bear, not all weeks are created equal," he said. ''They are losing three weeks at the best time of the year for feeding on the ice."