Earlier this month — over the course of five days — 97 percent of Greenland’s ice sheet thawed, The Atlantic reports. 

NASA says that it is normal for Greenland’s ice to melt a bit in the summer; what is unprecedented is the extent. Normally, only about half of the ice sheet sees any melting. This year, that proportion just about doubled. NASA additionally said that its satellites were recording uncharacteristically high temperatures over the island. 

Scientists are looking into whether this is normal or not, according to the magazine. 

Read more here. 

While NASA has called it an unprecedented event, it also says that it happens every 150 years or so — so which is it? Read more about that in the New York Times Dot Earth blog here.