Friday, August 28, 2009

Methane seepage heightens pressure for climate treaty

EurActiv: Evidence that methane, a dangerous greenhouse gas, is escaping from the warming Arctic seabed makes securing a new international agreement to slash global-warming gas emissions even more urgent, scientists warn.

A British-German research team discovered that over 250 plumes of methane bubbles are rising from the seabed off West Spitsbergen, a Norwegian island in the Arctic Ocean. The researchers discovered the seeps, which lie 150-400 metres deep, using sonar technology, they wrote in the Geophysical Research Letters earlier this month.

The methane was released from methane hydrates, "ice-like substances" that remain stable amid the high pressure and low temperature of marine sediments. Scientists have predicted that as ocean temperatures rise as a result of climate change, methane hydrates would begin to break down at greater depths. But the fact that the process has begun already surprised the team.

"Our survey was designed to work out how much methane might be released by future ocean warming; we did not expect to discover such strong evidence that this process has already started," said Professor Tim Minshull of the National Oceanography Centre at the University of Southampton in the UK. Data collected over past decades shows that 30 years ago methane hydrates were stable at water depths as shallow as 360 metres in the Spitsbergen area….

Svalbard reindeer in center of Longyearbyen, Svalbard, shot by Krzysztof Maria Różański, Wikimedia Commons, under the Creative Commons Attribution ShareAlike 3.0 License

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