Wednesday, July 25, 2012

This Fast

Strange, sudden and massive, according to the AP story.  It's the announcement by NASA that: " For several days this month, Greenland's surface ice cover melted over a larger area than at any time in more than 30 years of satellite observations. Nearly the entire ice cover of Greenland, from its thin, low-lying coastal edges to its two-mile-thick center, experienced some degree of melting at its surface, according to measurements from three independent satellites analyzed by NASA and university scientists.

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. According to satellite data, an estimated 97 percent of the ice sheet surface thawed at some point in mid-July."

That's almost all of the surface ice.  In four days.

Update: New evidence that melting is happening faster in the Antarctic as well.  News reports on the Greenland melt note that NASA suggests that whether the melt there will lead to an immediate rise in sea levels is unknown at this time, but possible.

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