NASA maps show how fast the Greenland glaciers are thinning and retreating right at the edge. OMG-Oceans Melting Greenland, A 5-year airborne and ship-based mission by NASA. To keep track of Greenland glacier. OMG determines the extent of Greenland glaciers melting from underneath. It conducted in-depth surveys using a ship equipped with sonar. Surveys show how much the warm water from the Atlantic eats away the coastal glaciers. While OMG is looking at the effects on ice sheets from below, NASA’s Operation IceBridge mission is surveying polar ice from above. For this mission, NASA aircraft flies around Greenland for few weeks each year. The aircraft uses Ice Surface Topography Interferometer (GLISTIN) technology. GLISTIN makes very High-Resolution Maps of the Ice. The overlap of OMG and IceBridge provides the most accurate measurements of changes in Greenland’s ice sheet mass. And the result is not Good. If the process goes on at this Rate, Global Sea Level can rise by 20 feet.