Climate Change: Methane Time Bomb

Climate Change
Large holes appearing in the Siberian permafrost have exacerbated concerns regarding the destabilization of methane hydrates in polar regions due to climate change. The first of these holes were identified in the Summer of 2014 in the Yamal Peninsula, which is approximately 2,000 miles northeast of Moscow. Numerous other craters have been identified in varying locations and the interest generated by them has now motivated University of Alaska geophysicist Vladimir Romanovsky to seriously consider investigating them in greater detail sometime this summer. These craters are just the latest signs of a continuing process of methane hydrate destabilization that has been going on for many years.

The Russian scientist Natalie Shakhova was one of the first to bring this problem to world attention back in 2010. In collaboration with fellow scientist Igor Semiletov, Shakova investigated an area known as the East Siberian Arctic Shelf or (ESAS). The two scientists discovered that methane was actively bubbling up from the ESAS sea bed. They returned to the region in 2011 and were horrified to find areas of destabilization as large as one kilometer in diameter. It rapidly became clear that, in conjunction with other areas around the northern hemisphere, such as certain locations around Greenland and Alaska, the vast Arctic store of methane as well as carbon was beginning to degenerate, threatening a potential contribution to greenhouse gas emissions of approximately 5,000 gigatons, which is slightly less than 10 times the amount already emitted by humans as a result of fossil fuel consumption.

The reason why this is a problem of hitherto unprecedented seriousness is that methane is much more potent that carbon dioxide as a greenhouse gas. It has a ‘warming potential’ of between 25 to 75 times that of one unit of carbon dioxide. If enough methane escapes into the atmosphere, both from land-based permafrost and methane clathrates on the sea bed in Arctic regions, it could trigger ‘runaway’ climate change, which is a process in which a ‘methane feedback loop’ enables global warming to feed itself in a climatic chain reaction that will be impossible for humans to stop. The beginning of such a process is known as a ‘tipping point’, and scientists have been worried about this potential phenomenon for decades.

This theory is not without its critics. For example, two prominent climate modellers, David Archer and Gavin Schmidt, argue that the methane release would have to continue for hundreds if not thousands of years before it threatened a tipping point. However, this is questioned, in turn, by British researcher Peter Wadhams, who has more than 30 years’ experience in the study of Arctic sea ice from Royal Navy submarines. Wadhams claims that the retreat of Arctic ice allows solar irradiance to warm the frozen methane deposits on the Arctic sea bed at an even greater rate, thus hastening the cycle.

Subsequent research by Shakova and Semiletov conservatively estimates methane emissions from ESAS at around 17 megatons per year, but that is twice the amount previously estimated by other scientists. Shakova’s paper, published in Nature Geoscience, has also found that the permafrost ‘cap’ covering the methane stored in the ESAS is heavily perforated and close to thawing.

In the light of Shakova’s previous research, the current craters increasingly look less like an interesting climatic phenomenon and more like the latest phase of a methane alarm bell that has been ringing for decades and one which the global community should have paid much greater attention to before now.

Opinion By Robin Whitlock

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