Saturday, April 11, 2009
MAKE NO mistake, Arctic Sea ice is melting. According to the National Snow and Ice Data Center and the National Aeronautics and Space Administration, the maximum extent of the winter sea ice cover for 2008-09 was the fifth-lowest on record. Underscoring their point, the agencies added, "The six lowest maximum events since satellite monitoring began in 1979 have all occurred in the past six years (2004-09)."
Global warming is doing a number on Arctic Sea ice. The report noted that the Arctic winter was 1.8 to 3.6 degrees Fahrenheit warmer than average. This and other factors are causing the surface ice to melt. That ice is vital for reflecting the light and heat of the sun. Without it, the heat warms the Arctic Ocean, which then melts the ice below the surface of the water. This, along with older ice moving out of the Arctic, decreases the thickness of sea ice cover, which then melts more easily in the summer. "Ice older than two years now accounts for less than 10 percent of the ice cover," according to the study. "From 1981 through 2000, such older ice made up an average of 30 percent of the total sea ice cover at this time of the year."
These new data come as predictions of an ice-free Arctic Sea during the summer get ever closer. Just two years ago, an NSIDC scientist estimated that worrisome event could happen within 20 to 30 years. Last month, Warwick Vincent, director of the Center for Northern Studies at Laval University in Quebec, told Reuters, "2013 is starting to look as though it is a lot more reasonable as a prediction."
That forecast, if proven true, would have dire consequences for the polar bear. A 2007 report from the U.S. Geological Survey revealed that a melting of Arctic ice caused by global warming would wipe out two-thirds of the world's polar bear population, estimated at 20,000 to 25,000, and all of Alaska's estimated 4,700 polar bears, by 2050. The polar bear is now listed as threatened under the Endangered Species Act. But we're all threatened as long as the build-up of greenhouse gases renders climate studies and models seemingly obsolete the moment they're released.