(Washington, DC) -- A top climate researcher says the Greenland ice sheet melted at a record rate in 2007.
According to Konrad Steffen of the University of Colorado at Boulder, it's the largest melting since satellite measurements began in 1979.
Steffen said, quote, "the amount of ice lost by Greenland over the last year is the equivalent of two times all the ice in the Alps, or a layer of water more than one-half mile deep covering Washington DC."
Researchers say if all of the ice in the region melted, it would be equivalent to a 21-foot sea level rise.
They add that melting has started earlier in recent years because of greenhouse gases in the atmosphere.
(Copyright 2007 by Newsroom Solutions)