The trouble with thaw

April 11, 2019

The warming Arctic permafrost may be releasing more nitrous oxide, a potent greenhouse gas, than previously thought

By Caitlin McDermott-Murphy

About one fourth of the Northern Hemisphere is covered in permafrost. Now, these permanently frozen beds of soil, rock, and sediment are actually not so permanent: They’re thawing at an increasing rate.

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From the first signs of thaw, scientists rushed to monitor emissions of the two most influential anthropogenic (human-generated) greenhouse gases (carbon dioxide and methane). But until recently, the threat of the third largest (nitrous oxide) has largely been ignored.

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Now, a recent paper shows that nitrous oxide emissions from thawing Alaskan permafrost are about twelve times higher than previously assumed. “Much smaller increases in nitrous oxide would entail the same kind of climate change that a large plume of CO2 would cause” says Jordan Wilkerson, first author and graduate student in the lab of James G. Anderson, the Philip S. Weld Professor of Atmospheric Chemistry at Harvard.

Since nitrous oxide is about 300 times more potent than carbon dioxide, this revelation could mean that the Arctic—and our global climate—are in more danger than we thought.

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