Meteorologist Eric Holthaus writes: On Monday, Greenland began to melt. Parts of Greenland melt every year and the whole thing freezes again each winter, but lately, thanks to global warming, the melting has come earlier and then peaked in the summer at higher levels than usual.

Even in light of these trends, Monday’s melt was unlike anything the scientists studying Greenland have ever seen — it was so different, in fact, that they thought the data was wrong.

“We had to check that our models were still working properly,” Peter Langen, a climate scientist at the Danish Meteorological Institute, told Polar Portal, a Danish government website which chronicles monitoring of the ice sheet. Sure enough, thermometers on and around the ice showed temperatures as high as 64 degrees Fahrenheit on Monday — more than 35 degrees warmer than normal for this time of year, and more typical of a warm day in July. [Continue reading…]