Disappearing lakes, old photos and AI are helping scientists map Arctic permafrost thaw in near-real time

Florida's sinkholes make the news, but Alaska's ground collapse problem is worse. Much of Alaska's soil is permafrost, rich in ice; when the ice melts, the ground can sink. As temperatures rise, it happens more often, damaging buildings, roads and pipes.

Scientists can't measure permafrost directly, but there's a clear sign: when ice-rich permafrost thaws, the ground subsides and fills with water, forming thermokarst ponds. These lakes are easy to spot on satellite imagery, and their changes reveal what's happening to the frozen ground below.

Sometimes a lake that took a millennium to form can drain completely in a few hours after an unusually warm summer. A disappearing lake is a strong signal that ice-rich permafrost has thawed.

Using aerial photos from the late 1940s and satellite imagery from the 1970s as a baseline, scientists apply AI to new images, quickly spotting new ponds or vanished lakes. They now monitor over 4 million lakes across the Arctic, including 70 million thermokarst ponds on Alaska's tundra.

In 2026, the Seward and Baldwin peninsulas in northwestern Alaska are hotspots for sudden lake drainages. In the summer of 2018 alone, nearly 200 of the region's ~4,600 lakes lost more than a quarter of their area. In June and July 2026, about 30 more lakes were affected.

Not all lake changes are due to permafrost thaw—spring meltwater or beavers can also alter lakes. Real-time data helps communities know where it's safe to build before new construction.