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Science in Seconds - Polar Bears

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Science in Seconds Know Everything Brit Trogen: Polar bears are on the run - ice floats melting at accelerating speeds, oil developments cropping up, pollutants like PCBs contaminating their food and constant appearances of ecologically-inaccurate Coke ads. According to the Polar Bear Specialist Group, between 20,000 and 25,000 bears remain worldwide, with 8 of the 19 subpopulations currently in decline and only one increasing. But while their future is uncertain, their evolutionary past is a true success story. According to mitochondrial DNA taken from an ancient jawbone, polar bears branched off from their closest relatives, the brown bears, 150,000 years ago. Within as little as 30,000 years of extremely rapid evolution, polar bears had adapted to a semi-aquatic lifestyle. But this timeframe means polar bears already survived global warming, 44,000 years ago. The last period of major interglacial warming on Earth had temperatures comparable to what we might see in a globally-warmed future. Polar bears may have taken refuge in Svalbard until temperatures dropped again. But researchers at the University of Iceland think their ability to adopt may have also helped. But just because they survived in the past, doesn't mean they will again. A 2007 United States Geological Survey predicted two-thirds of all polar bears would vanish by 2050, and go extinct soon afterwards. However, more recent models released in 2010 show that greenhouse gas regulation in the next decade or two will likely be enough to save them. So, while polar bears are still on thin ice, there's still hope. Courtesy of Science in Seconds – All rights reserved (Translators are invited to put their name here)

Video Details

Duration: 1 minute and 53 seconds
Year: 2011
Country: United States
Language: English
License: All rights reserved
Producer: Science in Seconds
Director: Science in Seconds
Views: 65
Posted by: tradottiinitaliano on Sep 10, 2011

The past and the avoidable future of a species at risk.

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