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| Earth on Mar 19, 2010

Can polar bears survive climate change?

If the Arctic melts completely during future summers, as some scientists have suggested it might, the polar bears’ habitat will be gone.

Polar bears have become a poster child for those who believe climate change will affect Earth dramatically in the coming century. Earth’s south polar continent – Antarctica – is solid ground covered with ice. But polar bears don’t live on the southern half of Earth’s globe. They live in the northern Arctic, which has no solid ground beneath its layers of sea ice. If Arctic ice melts completely during future summers, as some scientists have suggested it might, the polar bears’ habitat will be gone.

That’s why – although no one knows for certain how warm Earth might get in the coming century, or if the polar ice will become a polar sea – many fear for the fate of polar bears. For example, the U.S. Geological Survey projects that two thirds of polar bears will disappear by 2050.

There is a ray of hope, however. Research announced in early 2010 suggests that polar bears might be able to adapt quickly to a new habitat. The research centers on DNA from a rare fossil discovered in Norway in 2004.

Charlotte Lindqvist is research assistant professor in the University of Buffalo Department of Biological Sciences. She conducted this research with Stephan C. Schuster at Penn State. “Our results confirm that the polar bear is an evolutionarily young species that split off from brown bears some 150,000 years ago,” she said, “… perhaps adapting to the opening of new habitats and food sources in response to climate changes just before the last interglacial period.”

In other words, snowy white polar bears may have split from brown bears only 150,000 years ago, which is a blink of an eye in evolutionary terms.

The research centers on a rare, well-preserved, 110,000-to-130,000-year-old, fossil jawbone and canine tooth, found in the Svalbard archipelago of Norway. Lindqvist analyzed DNA extracted from the sample, and in 2008, compared it to tissue sames from modern bears.

These scientists emphasized that – while their data demonstrate polar bears have adapted in the past – it’s not certain that the polar bears therefore will also be able to adapt to current and future changes in the Arctic.

Lindqvist said, “Climate change now may be occurring at such an accelerated pace that we do not know if polar bears will be able to keep up.”

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