New research shows the surface of Greenland’s ice sheet melted over the course of four days this month to an extent not seen in more than three decades of monitoring. According to NASA, from July 8 to July 12, the thawed area jumped from 40 percent to 97 percent, meaning nearly the entire ice sheet surface had thawed. While about half the surface of Greenland’s ice sheet melts on average each summer, scientists have called this month’s thaw “extraordinary.” The unprecedented thaw comes after a chunk of ice twice the size of Manhattan detached from Greenland’s Petermann Glacier earlier this month.