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A Feedback Loop: The Alaska Tundra

A recent NASA report Alaska tundra source of early-winter carbon emissions provides another example of a feedback loop. Global warming has slowed the refreezing of the Alaska tundra allowing for increased CO2 releases.

A new paper led by Roisin Commane, an atmospheric researcher at Harvard University in Cambridge, Massachusetts, finds the amount of carbon dioxide emitted from northern tundra areas between October and December each year has increased 70 percent since 1975.

“In the past, refreezing of soils may have taken a month or so, but with warmer temperatures in recent years, there are locations in Alaska where tundra soils now take more than three months to freeze completely,” said Commane. “We are seeing emissions of carbon dioxide from soils continue all the way through this early winter period.”

How much carbon is stored in the frozen soils. According to the report

The soils that encircle the high northern reaches of the Arctic (above 60 degrees North latitude) hold vast amounts of carbon in the form of undecayed organic matter from dead vegetation. This vast store, accumulated over thousands of years, contains enough carbon to double the current amount of carbon dioxide in Earth’s atmosphere.

Methane Bubbles – A Feedback Loop

The Siberian Times brings us this article: 7,000 underground gas bubbles poised to ‘explode’ in Arctic

Their appearance at such high latitudes is most likely linked to thawing permafrost which in is in turn linked to overall rise of temperature on the north of Eurasia during last several decades,’ said a spokesman.

The summer was abnormally hot for the Yamal peninsula, with the air temperature reaching 35C.

This heat impacted on the depth of seasonal thawing which grew both deeper  spread wider than in the past, so causing the formation of new lakes and a noticeable change in the regional tundra landscape.

Scientists are simultaneously observing the sudden formation of the large craters, evidently caused by eruptions or explosions of methane gas which has melted below the surface.

This is another situation where warming permafrost is related to the release of the greenhouse gas methane, which then adds to warming. In other words, a positive feedback loop. There are some excellent photos in the article.

Melting Permafrost and a Feedback Loop

The BBC has a great article on a Siberian crater, the Batagaika crater, that is growing quickly due to melting permafrost. Excerpt from the article:

As more permafrost thaws, more and more carbon is exposed to microbes. The microbes consume the carbon, producing methane and carbon dioxide as waste products. These greenhouse gases are then released into the atmosphere, accelerating warming further.

“This is what we call positive feedback,” says Günther. “Warming accelerates warming, and these features may develop in other places. It’s not only a threat to infrastructure. Nobody can stop this development. There’s no engineering solution to stop these craters developing.”

The article provides some great context in understanding the impacts of global warming.