Thawing Siberian Permafrost
NASA Goddard Space Flight Center / CC BY

Large quantities of carbon in the form of carbon dioxide (CO2) and methane are trapped within and beneath polar permafrost, the layer of frozen ground that has not thawed for millennia. But this ground is now becoming destabilized as warmer temperatures due to a changing climate are causing the permafrost to melt, releasing the trapped greenhouse gases. If the melting is uneven it can cause the unmelted soil to collapse toward the melting soil, releasing the methane in an explosive way. This is exactly what scientists now believe caused the sudden appearance of multiple large craters in the Siberian Arctic this July. While the methane released from an individual crater is insignificant on a global scale, the appearance of these craters is an indicator that the Arctic habitat is changing more quickly than had initially been predicted, and the additive effects of these changes that lead to CO2 and methane release could indeed be a cause for concern.

The concern is that the Arctic has such large amounts of unprocessed carbon that even if a small fraction of it were released as methane or CO2 it could surpass humanity’s impact on the greenhouse effect in a single year. More importantly, the release of these gases from the Arctic could have a strong positive feedback on climate change, rapidly destabilizing the permafrost and causing the release of more trapped carbon. Although this is currently unlikely to occur, if climate change continues at its current rate then this scenario may no longer be out of question. Since climate change occurs more quickly at the earth’s poles, it will be important to keep our eyes on changes happening in the Arctic so that we have the best chance to prevent such a large scale release of carbon.

But the Arctic isn’t the only region where warmer temperatures threaten the release of trapped methane. Wetlands are the largest natural source of methane, and many of these regions are seasonally frozen at high altitudes, keeping methane release limited. A changing climate and warmer temperatures may perhaps have a larger and more immediate effect on this source of methane.

Edited by SITN Waves Editor Tyler Huycke. Thanks to Jason Munster and Alex Turner, graduate students in Environmental Sciences and Engineering at Harvard, for providing expert commentary and insight on the topic.

 

For more information on the the craters, see the Nature article:

http://www.nature.com/news/mysterious-siberian-crater-attributed-to-methane-1.15649

For further reading on methane in climate change, see the following SITN articles:

http://sitn.hms.harvard.edu/flash/2014/earth-climate-tipping-point/

http://sitn.hms.harvard.edu/flash/2014/is-global-warming-over/

 

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