Melting Greenland: The Greenland ice sheet is a vast body of ice covering 660,235 square miles, roughly 80% of the surface of Greenland. It is the second largest ice body in the world, after the Antarctic Ice Sheet. The ice sheet is almost 1,500 miles long in a north-south direction, and its greatest width is 680 miles. The mean altitude of the ice is 7,005 feet. And it is all melting. Freshwater losses in Greenland have accelerated since the early 1990s, with the south-east of the island seeing losses rise by 50 per cent in less than 20 years, according to new research from the University of Bristol.