Woods Hole - Warming Arctic's Higher Carbon Uptake Far Smaller Than Net Carbon, Methane Releases
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As the Arctic climate warms at twice the rate of the rest of the globe, the regions growing season is lasting longer each year. This means that plant growth is increasing, meaning that more of the greenhouse gas carbon is absorbed out of the atmosphere. However, new research from the Woods Hole Research Center (WHRC) has found that the melting of Arctic permafrost caused by the very same warming temperatures is releasing far more carbon and methane into the atmosphere.
The three-year project was the first study to determine net gains or losses in carbon emissions in the Arctic ecosystem through simulating warming in the field. Before the study, the understanding of permafrost feedbacks to climate change had been limited by a lack of data examining warming effects on both vegetation and permafrost carbon simultaneously, according to WHRC assistant scientist Dr Sue Natali. Natalis findings show that a longer growing season represents only a tiny silver lining to the Arctic melt.
There is 100 times more carbon stored belowground than aboveground in the Arctic, so observed changes in plant productivity are only a very small component of the story, she said.
Given the amount of carbon stored belowground in the Arctic, it is very unlikely that plant growth can ever fully offset carbon losses from permafrost thaw.
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Ed. - Emphasis in original
http://blueandgreentomorrow.com/2014/03/25/thawing-arctic-releases-more-carbon-than-it-absorbs/