HISTORY AND BEAR BIOLOGY SHOW WARMER TEMPERATURES AREN'T A THREAT
February 21, 2008
In early March, the polar bear could become the first species officially recognized by the U.S. government as threatened by global warming. The U.S. Fish and Wildlife Service (FWS) has proposed to list the polar bear as "threatened" under the Endangered Species Act (ESA) -- even though U.S. polar bear populations aren't declining.
Fortunately, says H. Sterling Burnett, a senior fellow with the National Center for Policy Analysis, comprehensive research demonstrates that since the 1970s -- while much of the world was warming -- polar bear numbers increased dramatically to approximately 25,000 today (higher than at any time in the 20th century).
Research conducted by the World Wildlife Fund shows that of the 20 distinct polar bear populations worldwide only two — accounting for about 16.4 percent of the total number of bears — are decreasing.
- Those populations are in areas where air temperatures have actually fallen, such as the Baffin Bay region.
- By contrast, another two populations — about 13.6 percent of the total — are growing, and they live in areas were air temperatures have risen.
Evolutionary biologist and paleozoologist Susan Crockford, of Canada's University of Victoria, points out that polar bears have historically thrived when temperatures were warmer than today's -- during the medieval warming 1,000 years ago and during the Holocene Climate Optimum 5,000 to 9,000 years ago.
Polar bears thrive during warmer climates because they are omnivores, like brown and black bears. Though seals are currently their primary food source, research shows that they have a varied diet and take advantage of other foods when those are available. Their diets can include fish, kelp, caribou, ducks, sea birds, the occasional beluga whale and musk ox and scavenged whale and walrus carcasses.
Source: H. Sterling Burnett, "Polar Bears on Thin Ice, Not Really! Redux," National Center for Policy Analysis, Brief Analysis No. 610, February 21, 2008.
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