Asian glaciers are set to shrink by at least a third by 2100 due to climate change, researchers said on Thursday, threatening the millions who depend on their meltwaters for drinking and farming.

Scientists warn that methane trapped beneath the Greenland ice sheet could intensify climate warming as the ice melts, releasing the potent greenhouse gas into the atmosphere at accelerating rates.

Caucasian glaciers have lost a quarter of their surface area to climate change since the millennium. “We don’t have winters here anymore,” said Sergei Nureddinov, a guest house owner in the mountaintop village of Verkhniy Kani, gesturing to the glacier from his front yard. “The climate catastrophe is here.”

All was quiet on June 22 as Canadian scientists David and Denise Holland settled in for the night off Greenland’s Helheim Glacier. But within minutes, five to eight billion tons of ice had broken off into the water.