The Heat Is Online

Polar Bears Endangered by Warming

Report says Arctic warming imperils polar bears, May 15, 2002

WASHINGTON - A reduction caused by global warming in the massive sheets of Arctic sea ice that polar bears prowl for their prey could have devastating consequences for the world's largest land predator, a leading conservation group said yesterday.

The World Wildlife Fund said in a report that polar bears are facing a series of threats, including large-scale habitat fragmentation, pollution and excessive hunting, but pointed to the climate change forecast to occur over the coming decades as the gravest of them all.

"The main message we're trying to bring forth here is that within the lifetime of our children, unless we do something now and starting taking steps, there is a serious risk of losing polar bears," Stefan Norris, lead author of the report, said in a telephone interview from Oslo, Norway.

The world's polar bear population currently numbers about 22,000 - 60 percent in Canada and the rest in the northernmost U.S. state of Alaska, Russia, Norway and Greenland. Polar bears, the biggest of the planet's eight species of bears, are not listed as endangered, but could suffer localized extinction or worse as a result of warming temperatures at the top of the world, the report said.

The report said early manifestations of the problem have been seen in the Hudson Bay region of Canada, which could be a harbinger of things to come for the huge white bears.

The scientific name of polar bears is Ursus maritimus, Latin for "bear of the sea" - and for good reason. The huge white bears are great swimmers, spending hours at a time in the icy water. But polar bears spend much of their time roaming the miles and miles of ice that cover the Arctic seas most of the year, hunting for prey such as the ringed seal.


The report said global warming, which many scientists blame on so-called greenhouse gas emissions from the burning of fuels and other sources, could drastically shrink the thickness and extent of this polar ice, erasing much of the bear's habitat. Many scientists believe polar regions are particularly sensitive to global warming.

The report said a warming trend has caused a 6 percent decline of Arctic sea ice since the 1970s. It added that computer models suggest there will be a 60 percent drop in summer sea ice in the next 50 years, which would increase the ice-free season from 60 to 150 days.

Diminishing ice cover and longer ice-free periods reduce the amount of time that polar bears have to spend on the ice hunting, meaning they will have fewer fat resources to survive during the lengthening summer season, the report said.

"The polar bear is the world's largest land-based carnivore. It is a symbol species of the Arctic," Norris said. "It is one of the few remaining large carnivore species found roughly in its original environment, and for some populations at close to its natural population numbers and densities."

It appears climate change already is affecting the condition of polar bears in the Hudson Bay area, the report said, noting female bears are in poorer condition going into the period for giving birth and raising cubs, suggesting difficulties getting enough food while hunting on the sea ice.

"When you lose your habitat, you have nothing," said Lara Hansen, WWF's senior climate scientist.

Pollution also is worrisome, the report said. It noted high levels of heavy metals such as mercury have been found in polar bears, radioactivity in the Arctic marine ecosystem has increased, and there is a mounting threat from toxic industrial chemicals and pesticides in the big predator's range.

Ian Stirling, a research scientist with the Canadian Wildlife Service and one of the foremost experts on polar bears, said the world's polar bear population is considered relatively stable, but the future is less certain.

"The threat is there. It's real," said Stirling, who offered advice on the report but was not an author. He noted the danger was not immediate but rather in the long term.