ON THINNING ICE

Feb 28, 2025

Given the massive global flooding problems that will occur if Greenland sheds its ice cap into the ocean, NASA and ESA want to monitor the ice with satellites. ESA’s CryoSat-2 has a radar altimeter that can see through clouds and ice all the way down to bedrock. NASA’s ICESat-2 has a laser altimeter that can gauge the ice surface but cannot see through clouds. The two agencies have put their satellites into similar orbits so they can combine data for more precise measurements. They found that Greenland ice has diminished by 2,347 cubic kilometers in 13 years — a little more than the combined volume of Lakes Ontario and Erie. The loss was greatest at the edges.