Over the last three decades, considerable warming has occurred in the Arctic, including Alaska. In a June 1997 workshop conducted by Gunter Weller and Patricia Anderson for the U.S. Global Change Research Program at the University of Alaska, scientists said that warming trends of up to 1 degree Celsius per decade in the annual mean have been observed. This exceeds the rate of change predicted by most numerical models for the high latitudes. Pronounced reductions in seasonal snow, glaciers, permafrost, and sea ice in the Arctic have occurred, including:
Sea-ice extent in the Bering Sea has been reduced by about 5 percent over the last 40 years, with the steepest decrease occurring in the late 1970s
Alaskan glaciers have receded generally, with typical ice-thickness decreases of 10 meters over the last 40 years, but some glaciers have thickened in their upper regions. A warming of 1 degree Celsius, if sustained, appears to reduce glacier length by about 15 percent of its original length.
Permafrost thawing also has caused landscape changes in forests, bogs, grasslands, and wetland ecosystems, affecting land use. Accelerated thawing has led to ground collapses and holes in the ground that in turn have forced costly increases in road maintenance and may in the future affect the Alaska oil pipeline. In addition, increased slope instability, landslides, and erosion have occurred in thawing permafrost, causing local floods.
For more information on the workshop, visit the Bering Sea Impacts Study website at http://www.besis.uaf.edu
For more information on climate change, check out EPA's website at http://www.epa.gov/globalwarming
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