Polars Bears Threatened by Melting Ice

The king of the Arctic may be going down.

Scientists who have devoted their lives to studying the polar bears that rule the far north say evidence increasingly shows the white behemoths may diminish in numbers in the coming years and possibly disappear entirely within a century.

The reason for the concern is global warming, which seems to be having its greatest impact so far on the polar regions, particularly the Arctic, the only place on the planet with polar bears. Warming trends of recent years have caused the ice pack that is so vital to the bears' survival to shrink, moving farther offshore and taking longer to form during the critical winter months when the bears load up on seals to get them through the summers.

Of course, it's a bit premature to say these clever hunters that adapted to one of the harshest environments on Earth can't make yet another adaptation to a warmer habitat, but experts are doubtful.

Leaner and Smaller

"We have grave, long-term conservation concerns for polar bears," says biologist Andrew Derocher of the University of Alberta. Derocher has spent two decades studying polar bears, including a six-year stint as the polar bear research scientist at the Norwegian Polar Institute in Tromso.

He is not alone in his concerns. Ian Stirling, an adjunct professor at the university who gained fame through his study of polar bears that have given the northern Canadian community of Churchill its identity, has documented a gradual decline in the well-being of those bears. They are leaner, smaller, and less able to find enough food to survive, according to Stirling.

That has forced many of the Churchill bears to prowl the community for scraps of food, thus threatening a tourism industry that is the town's primary source of revenue. One woman was killed by a bear there last year.

Both Derocher and Stirling blame the problem on the reduction of the polar bear's primary habitat, the ice field that blankets the circumpolar region for much of the year. As numerous scientific investigations have shown in recent years, that ice pack is thinner, smaller, and less stable than in previous years, all apparently because of record high temperatures in the Arctic.

"Polar bears are 100 percent dependent on sea ice," says Derocher. "It's the surface on which they do everything they do. They use it as a walking surface, it's a hunting surface, it's the place where they breed.

"And in particular, north of Alaska, it's also a place where very many of the bears make their maternity dens and give birth to their cubs. So basically, what you are talking about is a reduction in habitat."

Icebound Survivors

It's amazing it should come to this, considering the past survival triumphs of polar bears. They are believed to have evolved from the Siberian population of brown bears, which were isolated by glacial advances during the mid-Pleistocene era, according to the U. S. Fish and Wildlife Service.

For thousands of years they roamed the ice pack over the North Pole, turning their heavy mantle snow white. The first humans to cross into the New World encountered the bears, which became both prey and predator.

Clashes with polar bears are rare, but they do happen. Stories abound of hungry polar bears that have stalked a human, regarded as just another piece of meat in a land with not a whole lot else.

"They definitely will kill and eat humans, given the opportunity," says Derocher, but he says those encounters are rare.

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