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Monday, August 11, 2014

Crater Mystery Solved

The craters were a mystery: they started appearing in the Siberian permafrost, one almost a hundred feet across. Some people thought they were from meteors. Others said they were caused by aliens. Still others said they were caused by underground missile explosions.

Residents claimed to see the area smoking, and then there was a bright flash. Others said a celestial body fell there.

Well, now we know. The craters are caused by the explosion of methane gas, freed by the melting of permafrost, which in turn is caused by global warming. Temperatures in the arctic have gone up drastically: for example, Alaska's average temperature has increased 3.4 degrees in the last 50 years, and winter temperatures have increased 6.3 degrees.

Confirmation comes from Andrei Plekhanov, an archaeologist at the Scientific Center of Arctic Studies in Salekhard, Russia. The hole was discovered last year, after abnormally hot summers in 2012 and 2013. Plekhanov measured a methane level of almost 10% at the bottom of the crater. The normal atmospheric level of methane is 0.000179%.

This region of Siberia is home to huge natural gas fields. Permafrost, which covers millions of square miles in Alaska, Siberia and Canada, has large deposits of methane hydrates trapped in its ice. As temperatures rise due to global warming, the poles are heating up much faster than the lower latitudes.

This is not a new story: for years scientists have known that arctic lakes are emitting methane; there are lakes in Alaska and Canada that can be set on fire.

The permafrost is melting at an alarming rate, and as it melts, the methane hydrates will melt as well, releasing methane, a greenhouse gas even more potent than carbon dioxide. The melting also allows bacteria to feed on the plant material in the thawed permafrost, creating even more methane and CO2.

This is one of the feedback loops that climate scientists have been concerned about. As we warm the planet by entrapping more heat with the CO2 released by burning fossil fuels, we are accelerating the production of greenhouse gases from natural sources.

Methane hydrates are also found at the bottom of polar oceans. The oceans are heating up as well, and if the oceanic methane hydrates melt the problem will get a lot worse a lot faster than any of the climate models are predicting.

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