Methane frozen beneath Arctic seabed destabilising, scientists warn

Huge quantities of methane below the Arctic seabed are showing signs of destabilising, according to research conducted in the East Siberian Sea.

Scientists aboard Russian icebreakers have discovered that methane is leaking from the sub-sea permafrost far faster than had been previously estimated, raising concerns that climatic tipping points may have been reached.

As a greenhouse gas, methane is 25 times more powerful than carbon dioxide but emissions from subsea permafrost are not included in climate change prediction models.

“The sub-sea permafrost should act as a cap or seal, preventing leakage,” Natalia Shakhova, of the University of Alaska, told The Times. “Beneath it there is methane that has accumulated at high pressure. But the permafrost is losing its ability to be an impermeable cap.”

After water vapour and carbon dioxide, methane is the most significant of the gases that cause the atmosphere to retain heat. Levels have doubled since the beginning of the Industrial Revolution but 40 per cent of sources are natural, resulting from the decomposition of organic material in wetlands and other areas.

The permafrost that covers vast tracts of land in the far North is thawing, steadily adding methane to the atmosphere. The Arctic has warmed at about twice the rate of the rest of the planet. Climate scientists are concerned that as rising temperatures melt more permafrost, the added methane will raise temperatures further and so cause a wider thaw.

Dr Shakhova said: “The climatic consequences of this are hard to predict. This type of source has never been predicted by anyone and has not been included in climate models. We're going to keep studying this region and investigating why this is happening.

“Our concern is that the sub-sea permafrost has been showing signs of destabilisation already.”

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