It was reported in 2002 that Alaska's glaciers are melting more quickly than previously believed. Despite their relatively small land mass - about 13 percent of the world's total mountain glacier area - Alaska's glaciers contribute about half of all sea rise caused by glacial melt and about twice as much as the amount of water lost from the entire Greenland Ice Sheet. The rate of thinning has doubled in the past five years, compared to the 40 years before. As a result, the Alaskan contribution to sea-level rise has doubled, to about 0.27 mms a year during the past decade, or about twice the amount assumed by an international panel of scientists in 2001 that predicted sea level would rise up to 11 centimetres (about four inches) by the end of this century due to global warming.