Greenland's Glaciers Are Calving

At a very rapid pace.

Images retrieved from NASA satellites and cameras monitoring the island's glaciers revealed that a chunk measuring 11 square miles (29 square kilometers) broke away from the Petermann Glacier between July 10 and 24. For its part, Jakobshavn lost at least 3 square miles (10 square kilometers) since the end of the last melt season, and its northern section has broken up in recent weeks.

To make matters worse, the scientists observed an enormous crack forming back from the margin of the Petermann Glacier, which Box cautioned could point to "an imminent and much larger breakup" -- a loss that could amount to 60 square miles (160 square kilometers), or roughly one-third of the glacier.

At some point Greenland's rate of melting is going to be exponential and catastrophic. Miami and Manhattan are at sea level. Boston and Baltimore are at sea level.