Methane from the Arctic seafloor

Methane is a powerful greenhouse gas, so the addition of methane to the atmosphere is bad news for global warming and climate change (froma human perspective). Recent observations suggest that warming of the waters of the Arctic Ocean is triggering the release of plumes of gas (mostly methane) from beneath the seafloor into the ocean water column. So far there is no evidence that the gas is entering the atmosphere but some of it is converted to carbon dioxide which raises the acidity of the water. There is a brief report on this in New Scientist, Issue 2722 [22 August 2009] and a more lengthy piece, complete with a spectacular picture, on the BBC Website [18 August 2009].