One day there’s a lake in Greenland filled with 7 billion of gallons of water. A few weeks later, all that’s left is a mile-wide, 230-foot-deep empty crater. Before anyone goes building a shopping mall on the dry bed, another Greenland lake just like it has emptied and refilled twice in two years. Where are Greenland’s lakes going and why are they disappearing so fast?

According to a study reported in The Cryosphere, researchers at Ohio State University were using high-resolution satellite images to develop a map of the Greenland Ice Sheet when they noticed the sudden disappearance of a large lake that had been there for 40 years. This concerned team leader Ian Howat.

The fact that our lake appears to have been stable for at least several decades, and then drained in a matter of weeks — or less — after a few very hot summers, may signal a fundamental change happening in the ice sheet.

Howat, an associate professor of earth sciences at Ohio State, thinks the climate change is causing an excess of meltwater that exceeds Greenland’s natural plumbing system and causes what he calls “blowouts” – holes in the ice sheet that completely drain the lakes in just weeks.

The lake that empties and refills was found by geologists from Cornell University and reported in the journal Nature. Also using high-res images from NASA, they determined that the lake was drained and filled twice since 2012 and lost its water at a rate of 57,000 gallons (215 cubic meters) per second, or one 50-foot-long swimming pool per second. All of that draining and filling is not good for Greenland, according to study co-author Michael Bevis.

If enough water is pouring down into the Greenland Ice Sheet for us to see the same sub-glacial lake empty and re-fill itself over and over, then there must be so much latent heat being released under the ice that we’d have to expect it to change the large-scale behavior of the ice sheet.

Greenland is 70 to 80 percent ice so this rapid melting and lake disappearances, coupled with the unprecedented retreat of its glaciers, is of great concern not just to people who live there but to the rest of the world that will be dealing with rising waters.

Any wonder why the Doomsday Clock was adjusted?