The disappearance of two lakes underneath Greenland's ice sheets is a troublesome development for a part of the world already believed to be at high climate change risk.

According to CBS News, authors of a study published in the journal the Cryosphere found ice melt to be causing these lakes to drain quite quickly. In addition to the study in Cryosphere, a paper published in the journal Nature detailed the disappearance of a a similar case in a second Greenland sub-ice-sheet lake.

"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," Ian Howat, associate professor of earth sciences at Ohio State University (OSU) and lead author of the Cryosphere study, said in a press release.

Michael Bevis, a professor of earth sciences at OSU and a co-author on the Nature study, said these lakes drain so fast because the meltwater is warming the ice sheets holding it one place.

"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," he said in the release.

Carrying what is known as "latent heat," the meltwater opens larger passages for the lakes to drain into the ocean.

"Until we get a good map of the bed topography where this lake was, we have no idea whatsoever how many lakes could be out there," Howat said. "There may be something really weird in the bed in this particular spot that caused water to accumulate. But, if all you need is a bumpy surface a bit inland from the coast, then there could be thousands of little lakes."