Heat production from microbial metabolism of organic material in permafrost, during incubation at 16C. Observed heat production in 21 different organic-rich permafrost samples (in situ water content) grouped according to soil type and sample area. The n-values represent different location within a specific area, except for the Qajaa midden, where n represents the number of different archaeological layers investigated. Error bars show +1 s.d. For comparison, heat production from a mineral soil at Zackenberg is included. Graphic: Holleson, et al., 2015

[Is this what’s causing the explosive craters we’ve seen recently in Siberia? –Des]

By Emily Atkin
8 April 2015

(Climate Progress) – Scientists might have to change their projected timelines for when Greenland’s permafrost will completely melt due to man-made climate change, now that new research from Denmark has shown it could be thawing faster than expected.

Published Monday in the journal Nature Climate Change, the research shows that tiny microbes trapped in Greenland’s permafrost are becoming active as the climate warms and the permafrost begins to thaw. As those microbes become active, they are feeding on previously-frozen organic matter, producing heat, and threatening to thaw the permafrost even further.

In other words, according to the research, permafrost thaw could be accelerating permafrost thaw to a “potentially critical” level.

“The accompanying heat production from microbial metabolism of organic material has been recognized as a potential positive-feedback mechanism that would enhance permafrost thawing and the release of carbon,” the study, conducted by researchers at the University of Copenhagen’s Center for Permafrost, said. “This internal heat production is poorly understood, however, and the strength of this effect remains unclear.”

The big worry climate scientists have about thawing permafrost is that the frozen soil is chock-full of carbon. That carbon is supposed to be strongly trapped inside the soil, precisely because it’s supposed to be permanently frozen — hence, “permafrost.”

However, as temperatures in the Arctic have risen due to human-caused climate change, permafrost is thawing, and therefore releasing some of that trapped carbon into the atmosphere. It’s yet another feedback loop manifesting itself in Arctic permafrost regions — as climate change causes it to thaw, the thawing causes more climate change, which causes more thawing, et cetera, et cetera.

What makes this new research so important is that it adds to the urgency of stemming permafrost thaw. Because even without this new discovery of heat-producing microbes, estimates for carbon releases from thawing permafrost have been alarmingly large. According to the National Snow & Ice Data Center, there are about 1,700 gigatons of carbon currently frozen in permafrost — more than the total amount in the atmosphere now (Earth’s atmosphere contains about 850 gigatons of carbon, according to the Center).

Without considering microbes, the average estimate is that 120 gigatons of carbon will be released from thawing permafrost by 2100, which would raise the average global temperature 0.29 degrees. After 2100, if climate change worsens, total permafrost emissions roughly double. That’s confirmed by National Snow and Ice Data Center research scientist Kevin Schaefer’s research, which took the average of 15 peer-reviewed estimates of future carbon releases from thawing permafrost.

Schaefer, who was also one of the reviewers of the microbe study, told ThinkProgress that this is particularly alarming because emissions from permafrost are “completely irreversible.”

“These are permanent emissions,” he said. “Once you thaw out that material, there’s no way to put that organic matter back into the permafrost … you can’t re-freeze the permafrost.” [more]

Why This New Study On Arctic Permafrost Is So Scary

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