Courtesy NASAJohnny Carson used to have a standard round of jokes for the summertime on his Tonight Show.
"How hot is it outside today? It's so hot (insert punchline)," was the standard humorous convention he would use.
NASA researchers have a new take on how hot it is this summer, and it's not that funny. Satellite photos taken this month over Greenland show that the massive ice sheet that covers almost all of the Arctic region island was now melting at some degree earlier this month. Like the tried-and-true diet ads in the back of magazines, NASA has before and after satellite images that show the extent of melting that happened.
The top image, complied from three satellite photos taken on July 8, show about 40 percent of the ice sheet's surface was melting. Areas that are pink show where melting is occurring. Areas that are white show non-melting ice and areas that are grey have no ice cover.
Courtesy NASAThe bottom image, taken on July 12, shows a rapid acceleration of melting on the island, with 97 percent of the ice sheet melting. It's a surge in melting rates that scientists figure happens about once every 150 years. This month's data is the highest melting rate that NASA has seen in Greenland since satellite data has been collected for about 30 years.
A rare warm front stalling over Greenland is the cause of the high amount of melting and by the middle of the month, that front had moved on and things were getting back to normal. You can read the NASA press release about this weather event here.
While the brief massive melting is unusual, it's not a huge immediate threat to Greenland's ice sheet, which is some spots is more than two miles thick.
In other recent Greenland ice sheet news, a huge chunk of coastal ice broke off and is now adrift in the Atlantic Ocean earlier this month. Measuring 59 square miles, the ice sheet is twice the size of Manhattan. You can read more about that story here. Two years ago, an iceberg twice as big as this year's broke off from the same location. Experts say it's extremely rare to have two huge icebergs break loose in such a short amount of time.