SEATTLE, July 6 -- 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 a panel of the world's leading experts on the species.
In a closed meeting here
late last month, 40 members of the polar bear specialist group of
the World Conservation Union concluded that the imposing white
carnivores -- the world's largest bear -- should now be classified
as a "vulnerable" species based on 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.
"The principal cause of this
decline is climatic warming and its consequent negative affects 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 of 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 U.S. 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 U.S. government.
The panel's conclusions
became public this week as President Bush traveled to a Group of
Eight meeting in Scotland, where U.S. officials have lobbied to
prevent any specific targets for reducing greenhouse gases from
being included in the meeting's final communique. The United States
is the only member of the G-8 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
from the western coast of Hudson Bay, in the Canadian province of
Manitoba. It shows a 17 percent decline in the polar bear population
in the past 10 years, from 1,200 to fewer than 1,000. The panel here
in Seattle used the Canadian research as the primary 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,
and that is affecting the survival of the bears," said Ian Stirling,
a research scientist for the Canadian Wildlife Service.
Ice is melting there about
three weeks earlier than it did 30 years ago, said Stirling, who has
been studying polar bears for 35 years.
"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, when seal pups are
abundant and bears put on fat that they store for the four months
that they have to live onshore."
Having lost this critical
hunting opportunity, polar bears in western Hudson Bay weigh about
15 percent less (about 150 pounds less for an adult male) than they
did 30 years ago, Stirling said.
"The bears are losing their
physical condition," he said. "It is a cumulative process that is
causing a steady decline in survival, particularly for cubs and
sub-adults. It is causing the population to decline."
In Alaska, the ice situation
appears to be equally "grim" for polar bears, Schliebe said. He said
that in three of the past four years, there have been record low ice
packs in Alaska's Beaufort Sea region, pushing more and more polar
bears on land for protracted periods. Hungry bears are drawn to
village dumps and other settled areas where they come into conflict
with people and are sometimes shot.
Polar bears evolved from
brown bears about a quarter-million years ago to become specialist
carnivores, marine mammals that can thrive on ice packs and feast on
seals. Climate change, though, is happening too fast for the bears
to adapt, experts say.
"They don't have time to
evolve backwards," Stirling said.