The Peril in Polar Bears

Andy Revkin has been an environment reporter for The New York Times since 1995. Revkin has traveled to the Artic three times, and he was the first New York Times reporter to file stories and images from the North Pole. He is the author of THE NORTH POLE WAS HERE: Puzzles and Perils at the Top of the World

A week ago, Tim Flannery, a well-known Australian writer and environmentalist, warned that global warming poses such a serious threat that the bears have begun to drown in the waters they call home -- and could soon perish altogether.

"The projections of the polar bear specialists are that by about 2030, around that date, the species will be extinct," he told CBC Radio.

"And that is, I think, an extraordinary, extraordinary implication."

Flannery came to Canada to promote his bestselling new book, The Weather Makers. His claims prompted sympathetic articles in many newspapers.

But Ian Stirling, Canada's leading expert on polar bears, said the bears are in no imminent danger of disappearing, and such claims add dangerous hyperbole to a serious debate.

"I don't think it's helpful to make apocalyptic predictions unless there's really some solid ground," he said. "And the information that we do have suggests they won't be extinct in that period of time."

An estimated 22,000 polar bears roam the northern world, 15,000 of them in Canada, where they are divided into 13 populations. For three decades, Stirling has studied the southernmost group, which lives in the Hudson Bay area and has already shown substantial evidence of being hurt by a warming climate.

The bears have lost 15 to 20 per cent of their weight, and their local numbers have shrunk about 20 per cent. The change is partly attributable to hunting, but also to climate change. Polar bears rely on ice to hunt seals, and Hudson Bay now melts three weeks earlier than it did 30 years ago.

"Early May through to (ice) breakup is the peak feeding time," said Stirling. "Sixty to 80 per cent of the energy that they'll use throughout the year is taken in in that spring period, so the loss of three weeks of feeding at the most important time of the year is quite significant."

In addition, the Hudson Bay bears have all but stopped giving birth to triplets, and the time it has taken to wean cubs has grown by a year, to 30 months.

Still, the impacts of climate change have not yet been as severe in the Far North as they have in Hudson Bay.

Only an Arctic that is ice-free year-round could wipe out polar bears altogether, said Stirling -- and that has not happened in a very long time.

"There were certainly times in the past where there does not appear to have been ice on the Arctic Ocean," said Humfrey Melling, a research scientist with the Fisheries and Oceans Department. "Say, 30 million years ago, the shores of the Arctic had forests."

There's nothing in any projection that could ever get rid of the Arctic's ice in the winter, because ultimately there is no sun, adds Andrew Weaver, who holds the Canada research chair in atmospheric science at the University of Victoria. "There will always be ice in the winter, and when I say always, always is as long as it's worth predicting -- like thousands and thousands of years."

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