May 14, 2008
Posted: 04:31 PM ET
Okay. I posted a couple of sentences here shortly after the U.S. put the polar bear on the threatened species list this afternoon, and producer Marsha Walton wrote a news story with the details. What followed was a flurry of reader responses: A mix of well-reasoned arguments, political diatribes both for and against, and a bear recipe or two.
Here are a few baseline observations to help guide further discussion, and (polite) argument:
Are Polar Bears Declining? The International Union for the Conservation of Nature put together the most recent authoritative survey of bear populations three years ago. They report that of nineteen separate sub-populations of polar bears residing off the coasts of Alaska, Canada, Greenland, Norway, and Russia, "five are declining, five are stable, two are increasing, and seven have insufficient data on which to base a decision."
Are There More Polar Bears Than There Used to Be Thirty Years Ago? Almost certainly, yes. But this is at least in part due to reductions and restrictions in hunting. In this country, the U.S. Marine Mammal Protection Act outlawed the killing of polar bears in the early seventies, with some exceptions for traditional native hunters. Often-cited numbers that polar bears are five times more numerous than they were in the 60's or 70's are on thin ice, though: Old numbers estimating a population of only 5,000 bears back then were based in part on guesswork, and are not considered reliable by many bear scientists.
So do Polar Bears have a Rosy Future? The Bush Administration based its decision on science from the US Geological Survey and the US Fish and Wildlife Service. The scientists, and the Bush Administration acknowledge a rapid loss of the bears' sea ice habitat, and a strong likelihood that their situation will get worse. (The USGS link goes to a page of links to recent surveys of both polar bear populations and ice cover) Here's the key phrase in the USGS research: "Projected changes in future sea ice conditions, if realized, will result in loss of approximately 2/3 of the world's current polar bear population by the mid 21st Century. Because the observed trajectory of Arctic sea ice decline appears to be underestimated by currently available models, this assessment of future polar bear status may be conservative."
What's Happening with Arctic Sea Ice? The U.S. Government's National Snow and Ice Data Center projects "lower than average ice cover" this summer for the Arctic, on the heels of last summer's record-low ice coverage. Keep an eye on this link over the next few months to see how low the ice cover goes.
What's the Difference between an "Endangered" species and a "Threatened" species? Interior Secretary Kempthorne, in listing the species as "Threatened, " acknowledged that declining ice cover due to global warming could lead to a risk of extinction at some point in the future. An "Endangered" species is one that is determined to be in imminent danger.
Peter Dykstra Executive Producer CNN SciTech & Weather
Filed under: Uncategorized
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