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Sunday, September 23, 2012

Semiletov & Shakhova have discovered more than 200 sources of methane emissions in the Arctic, Laptev Sea

Methane emission in the Arctic – a possible key to the global warming
by Maria Dunayeva, Voice of Russia, September 18, 2012

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Photo: RIA Novosti

Russian scientists have discovered more than 200 sources of methane emissions in the Arctic, particularly in the north of the Laptev Sea. Two of the methane fields exceed 1 kilometer in diameter, said Igor Semiletov, expedition head aboard the Viktor Buinitsky research vessel. Methane emissions in the Arctic have been observed before and are explained by bacterial activity. Head of the ecology department at Moscow State University, Dmitry Zamolodchikov, spoke about the possible consequences in an exclusive interview with the Voice of Russia.

How would you comment on this discovery by Russian scientists?

Different examples of methane emissions in Arctic coastal regions and in the tundra systems have been observed over the last 20 or 30 years. There is really nothing surprising about this. Because, first of all, we are talking about frozen substances and cold conditions in the coastal area, in addition to the water pressure, all of which make perfect conditions for so-called gas hydrates. That is a bond between methane and water, which looks like snow, and is fairly unstable. Gas hydrates can quite easily break and can cause, correspondingly, methane emissions. Methane emerges as a result of bacteria activity in an environment with little oxygen which decomposes organic substances. The tundra has a humid climate, meaning it has the perfect conditions for the methane-producing bacteria. In that sense tundra is the source of methane and these bacteria are active in this region. In other words the Arctic has many mechanisms for production of natural methane. There are many mechanisms that conserve methane, for example gas hydrates. Many of those mechanisms are broken at higher temperatures. Therefore, in some cases, mass emissions of methane can be observed.

What consequences can mass methane emission lead to?

That is a complicated question. Scientists who study this, and there are quite a few of them, follow two opposing opinions. There is the view that it could lead to catastrophic consequences in the nearest future, because the process of methane emission will only grow. Methane is a potent greenhouse gas which will induce higher temperatures and will have the effect of a self-expanding wheel which is rolled down a hill, meaning that the process will go faster and faster. It will threaten our planet with countless disasters and horrible consequences. Yet another group of scientists believes that, because it is a natural process, there are both positive feedbacks that amplify methane emissions and negative feedbacks which lead to the increase of methane absorption. Beside the methane-producing bacteria there are also methanotrophic bacteria. Curiously enough they consume methane during the course of their life, they do so because if we combine methane with oxygen we get energy. In natural ecosystems both types of bacteria are present. The ones that consume methane live where there is enough oxygen, and those who produce methane live where there is little oxygen. It is a hard to know how the balance between synthesis and consumption of methane is reached, because warming in the tundra can reduce humidity in the region, causing methanotrophs. Meaning there are processes which amplify methane production and consumption. It is possible that in the future we will have a situation where balance between production and consumption of methane will be reached.

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