Two subglacial lakes below the ice sheets of Greenland have drained away, worrying scientists who fear that climate change is causing major impacts in the region.

Scientists found that the first lake, which had contained 7 billion gallons of water, had disappeared, and a crater stretching 1.2 miles across and 230 feet deep was all that was left, according to a CBS News report.

This would indicate that meltwater has begun to overflow the natural plumbing system present in the ice sheets, resulting in blowouts that cause the lakes to drain away, according to Ian Howat, who led a team at Ohio State University that discovered the crater and described their findings in the journal The Cyrosphere.

Despite being stable for decades, it only took weeks for the lake to drain, Howat said. This indicates a fundamental change within the ice sheet.

Another team from Cornell University found that a two-mile-wide lake had drained twice in the last few years, and at one point had experienced a blowout that sucked 57,000 gallons of water out of the lake every second. The lake was refilled by meltwater, which is not a good sign. as the meltwater becomes trapped and releases heat that softens the surrounding ice, which will increase the ice flow.

The Greenland ice sheet has lost 10 billions of tons of ice per year since 2003, which could contribute to rising seas on the Earth. In just the last decade, Greenland’s Zachariae glacier has retreated 12.4 miles, a breakneck pace for a glacier.

Scientists believe melting is intensifying due to climate change caused by increased carbon emissions around the globe over the last century. They are noticing more surface lakes in Greenland, and finding them farther inland and at higher altitudes.