Polar bears and warming periods throughout history


Q: Why does everyone make such a big deal about the polar bears when global warming comes up in conversation? Polar bears have survived previous warming periods, haven’t they? – Matt, TN

A. Polar bears have gotten a lot of press lately, we’ll grant you that. And yes, most scientists estimate that polar bears have been around for about 200,000 years, meaning they’ve survived other warming periods. But before you become hardened to the sight of those adorable white fluffy polar bear faces, consider this: unlike past warming periods, which have occurred over thousands of years, the climate change occurring now is moving at an unprecedented rate. “The amount of ice we’ve lost over the last 15 years usually takes about 1500 years to happen,” says Robert Buchanan, President of Polar Bears International. Last year, we lost a disturbingly large chunk of ice—about 1 million square miles—and we’re expected to surpass that amount this year. This speedy climate flux means that it’s unlikely polar bears will adapt in time to survive the changes, says Buchanan, as they have in past warming periods. Buchanan  says that asking polar bears to adapt to survive today’s rapid warming rate would be like asking a human to quickly evolve back into primates. “I don’t think we’re going to start swinging from the trees anytime soon!” he jokes.

The U.S. Geological Survey agrees, finding that future reduction of Arctic sea ice could result in a loss of two-thirds of the world's polar bear population within 50 years. Fortunately, this rather dire prediction does present one silver lining—it recently earned polar bears a spot on the Endangered Species list, which just may be the great white bears’ last hope.

-         Jessica A. Knoblauch

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Comments

It should also be noted that estimates for the last time the polar ice cap melted out, as is currently happening, range from 700,000 to 4,000,000 years ago... both far longer than polar bears have been around. So yes, they've lived through warming periods, but never one like this.

BTW, Homo Sapiens have been around for about 250,000 years... so this is a first for us too.

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