Bubbles of methane mark a lake where permafrost is melting below and quickly releasing greenhouse gases into the atmosphere.
Credit: Katey Walter Anthony/ University of Alaska Fairbanks

But when that happens below thermokarst lakes, the process is even grimmer because the water at the surface speeds up the melting below. The released gases, built with carbon atoms between 2,000 and 43,000 years old, quickly rise up through the lake and into the atmosphere.

"Within decades you can get very deep thaw-holes, meters to tens of meters of vertical thaw," Walter Anthony said in the statement. "So you’re flash thawing the permafrost under these lakes. And we have very easily measured ancient greenhouse gases coming out."

Moreover, the team also found that this abrupt thawing was still a concern even under a scenario in which humans tried to rein in their greenhouse-gas production and slow climate change. And, of course, the more permafrost melts, the faster the melting continues — making all this grim news indeed.

The research is described in a paper published Wednesday (Aug. 15) in the journal Nature Communications.