Skating on Thin Ice
Posted September 6, 2007
One of the most dramatic and visual manifestations of global warming is the declining expanse of arctic sea ice. The data coming out of the Arctic now are shocking even to those of us who read bad news about global warming for a living. Scientists at the National Snow and Ice Data Center are now tracking Arctic sea ice expanse in real time and a new record low is being set just about every day. As of September 4, 2007 Arctic sea ice extent was 4.42 million square kilometers (1.70 million square miles), almost 20 percent lower than the record low set on September 20-21 2005. September typically has the lowest monthly average sea ice extent, but August 2007 has already set the record for the lowest monthly average ever recorded by satellite for any month—a startling 31% below the average for all Augusts since 1979. We can expect new record daily lows through at least the middle of September and a new record monthly low when the full month’s data come in.
Climate models predicted abrupt and widespread sea ice melting early in the 21st century, beginning as soon as 2015, but it seems that the real world continues to outpace even worse case scenarios. Arctic sea ice is already floating so melting it does not add to sea level, but it does accelerate global warming because sea ice is better at reflecting back the sun’s rays than is open water, which absorbs more solar heat. Melting glaciers, on the other hand, do add to sea level and they are also melting faster than expected according to Mark Meier of the University of Colorado and colleagues who reported their findings in the August 24th issue of Science.
You can read more about these and other recent scientific findings in the Science Update I recently compiled for distribution to Congressional offices. Its not a pretty picture, but if pictures are worth a thousand words maybe the image of the shrinking ice cap will help compel Congress to act.
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