In widely reported findings, UGA climatologists and NASA independently confirm that during several days this month, nearly the entire ice sheet of Greenland experienced some degree of melting on its surface.
On average, about half of the surface of Greenland's ice sheet naturally melts in the summer. The new data—from three different satellites—show that an estimated 97 percent of the ice sheet surface thawed at some point in mid-July.
"This is the first time we have witnessed almost all of the ice sheet melt in the three decades of satellite data," said Thomas Mote, professor and head of the department of geography in the UGA Franklin College of Arts and Sciences. "The last time this occurred was more than 100 years ago, long before satellite data were available."
Glaciologists characterized the melting as natural though uncommon, so uncommon in fact that scientists at NASA's Jet Propulsion Laboratory initially questioned their own findings, though colleagues at UGA and the City University of New York confirmed the melt recorded by satellites. It is very difficult not to editorialize about so dramatic a report as this in the wider context of global climate change. But one thing is certain: scientists are doing their jobs. Multiple research stations within academia and not, using the very latest in deployed technology to monitor the Earth's climate for these changes and help each other verify their findings and report to the public with as much accuracy as possible. Now it is up to others in government, politics, industry and the media to respond accordingly.
Image: Extent of surface melt over Greenland's ice sheet on July 8, left, and July 12, right. Measurements from three satellites showed that on July 8, about 40 percent of the ice sheet had undergone thawing at or near the surface. In just a few days, the melting had dramatically accelerated and an estimated 97 percent of the ice sheet surface had thawed by July 12. In the image, the areas classified as "probable melt" (light pink) correspond to those sites where at least one satellite detected surface melting. The areas classified as "melt" (dark pink) correspond to sites where two or three satellites detected surface melting (Credit: Jesse Allen, NASA Earth Observatory and Nicolo E. DiGirolamo, SSAI and Cryospheric Sciences Laboratory)