The Greenland ice sheet is a vast body of ice covering 660,235 sq miles, roughly 80% of the surface of Greenland. It is the second largest ice body in the world, after the Antarctic Ice Sheet. Some scientists predict that climate change may be near a "tipping point" where the entire ice sheet will melt in about 2000 years. If the entire 2,850,000 cubic kilometres (683,751 cu mi) of ice were to melt, it would lead to a global sea level rise of 7.2 m (23.6 ft).
The ice in the current ice sheet is as old as 110,000 years. The presence of ice-rafted sediments in deep-sea cores recovered off of northeast Greenland, in the Fram Strait, and south of Greenland indicated the more or less continuous presence of either an ice sheet or ice sheets covering significant parts of Greenland for the last 18 million years.
During winter, the ice sheet takes on a clear blue/green color. During summer, the top layer of ice melts leaving pockets of air in the ice that makes it look white.