Arctic lakes are drying up, according to a new study.

The Arctic is no stranger to loss. As the region warms nearly four times faster than the rest of the world, glaciers collapse, wildlife suffers, and habitats continue to disappear at a record pace.

The new research reveals that over the past 20 years, Arctic lakes have shrunk or dried completely across the pan-Arctic, a region spanning the northern parts of Canada, Russia, Greenland, Scandinavia, and Alaska.

The findings offer clues about why the mass drying is happening and how the loss can be slowed.

SURPRISING ARCTIC LAKE DECLINE
The vanishing lakes act as cornerstones of the Arctic ecosystem. They provide a critical source of fresh water for local Indigenous communities and industries. Threatened and endangered species, including migratory birds and aquatic creatures, also rely on the lake habitats for survival.

The lake decline comes as a surprise. Scientists had predicted that climate change would initially expand lakes across the tundra, due to land surface changes resulting from melting ground ice, with eventual drying in the mid-21st or 22nd century.

Instead, it appears that thawing permafrost, the frozen soil that blankets the Arctic, may drain lakes and outweigh this expansion effect, says Elizabeth Webb, a postdoctoral researcher in the biology department at the University of Florida, and lead author of the study in Nature Climate Change.

Webb and colleagues theorized that thawing permafrost may decrease lake area by creating drainage channels and increasing soil erosion into the lakes.

“Our findings suggest that permafrost thaw is occurring even faster than we as a community had anticipated,” Webb says. “It also indicates that the region is likely on a trajectory toward more landscape-scale drainage in the future.”

COUNTERINTUITIVE FINDING
In addition to rising temperatures, the study also reveals that increases in autumn rainfall cause permafrost degradation and lake drainage.

“It might seem counterintuitive that increasing rainfall reduces surface water,” says Jeremy Lichstein, Webb’s advisor and a study coauthor. “But it turns out the physical explanation was already in the scientific literature: rainwater carries heat into the soil and accelerates permafrost thaw, which can open up underground channels that drain the surface.”

If accelerated permafrost thaw is to blame, that’s unwelcome news. The Arctic permafrost is a natural warehouse of preserved organic matter and planet-warming gases.

“Permafrost soils store nearly two times as much carbon as the atmosphere,” Webb says. “There’s a lot of ongoing research suggesting that as permafrost thaws, this carbon is vulnerable to being released to the atmosphere in the form of methane and carbon dioxide.”

Read the full article about Arctic lakes at Futurity.