12 hours after posting “Do the math, goodbye Artic . . .” NASA released satellite data indicating that for the first time since records have been taken, the summer ice melt covered the whole of Greenland including the highest point 2 miles above sea level. (It should be clear that this refers to “ice melting” over 97% of Greenland, NOT that the “ice disappeared” over 97%. The land ice at points is 3,000 metres thick, that is why a sea level rise of 7.5 metres SHOULD the ice disappear, is forecast).
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.
“On average in the summer, about half of the surface of Greenland’s ice sheet
naturally melts. At high elevations, most of that melt water quickly refreezes
in place. Near the coast, some of the melt water is retained by the ice sheet
and the rest is lost to the ocean. But this year the extent of ice melting at or
near the surface jumped dramatically.
This extreme melt event coincided with an unusually strong ridge of warm air, or a heat dome, over Greenland. The ridge was one of a series that has dominated Greenland’s weather since the end of May. “Each successive ridge has been stronger than the previous one,” said Mote. This latest heat dome started to move over Greenland on July 8, and then parked itself over the ice sheet about three days later. By July 16, it had begun to dissipate.”