Heat Wave Causes Massive Melt of Greenland Ice Sheet 

COPENHAGEN, DENMARK - Greenland's ice sheet has experienced a "massive melting event" during a heat wave that has seen temperatures more than 10 degrees above seasonal norms, according to Danish researchers.

Since Wednesday, the ice sheet covering the vast Arctic territory has melted by about 8 billion tons a day, twice its normal average rate during summer, reported the Polar Portal website, which is run by Danish researchers. The Danish Meteorological Institute reported temperatures of more than 20 degrees Celsius (68 Fahrenheit), more than twice the normal average summer temperature, in northern Greenland. And Nerlerit Inaat airport in the northeast of the territory recorded 23.4 degrees C (74.1 F) on Thursday — the highest recorded there since records began.