While it has been known for some time that the polar bear is in trouble, new research shows that Arctic ice--the polar bear's primary habitat--is melting much faster than scientists had believed, says U of A biologist Dr. Andrew Derocher.

"The climate predictions coming out are showing massive changes in sea-ice distribution," said Derocher, who follows polar bears to see how they adapt to changing conditions. If the predictions are correct, he says, "we'll certainly lose polar bears in a lot of areas where we currently have them." Ice conditions in the Beaufort Sea, for example, are already changing dramatically.

The world's largest terrestrial carnivores, polar bears rely on sea ice to survive, using it to pass between forest dens and hunting grounds where they prey on seals. There are about 15,000 polar bears in northern Canada, accounting for about two-thirds of the world's total population.

Derocher shared his views Jan. 6 at a symposium on Arctic biology in Toronto. It was the biggest gathering of Canadian Arctic biologists in more than a decade, says co-chair Dr. David Hik, also of the U of A. Many of the talks addressed the impact of climate change on northern ecosystems.

Derocher says if global warming continues unchecked, some remnant populations of polar bears may manage to hang on in the high Canadian archipelago or on permanent polar ice at very high latitudes. But the potential for extinction is still a cause for concern: "You don't have to be a polar scientist to see that if you take away all the sea ice, you don't have polar bears any more."

To make matters worse, sea-ice melting is accelerated by "positive feedback loops." Sea ice acts as a reflector of solar energy, but when the ice disappears, the ocean absorbs that heat energy, which in turn prev
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Contact: Phoebe Dey
phoebe.dey@ualberta.ca
780-492-0437
University of Alberta
8-Jan-2003