For the first time, NASA has accurately mapped the ice sheets covering Greenland in order to highlight significant changes in the ice's elevation. The study shows that in some areas, the island's ice sheet is thinning at a rate of more than 1m (3.3ft) a year. A shrinking ice sheet could result in higher sea levels. "A net loss of approximately 51km3 of ice a year from the entire ice sheet is sufficient to raise the global sea level by 0.005in [0.127mm] a year, or approximately 7% of the observed rise," says Bill Krabill, project scientist at NASA Goddard Space Science. The ice sheet, which covers 85% of Greenland, was mapped using an airborne laser altimeter and precision global positioning satellite receivers. Blue areas on the image indicate where the loss of ice is greatest, yellow areas show ice thickening and grey areas show no significant change. NASA's ICESat spacecraft, to be launched next year, will take routine measurements of the Greenland and Antarctic ice sheets.


Source: Flight International