New global warming threat as scientists discover massive methane 'time bomb' under the Arctic seabed



Global warming could rapidly accelerate as millions of tons of methane escape from beneath the Arctic seabed, scientists warned today.

Huge deposits of the greenhouse gas - 20 times more potent than carbon dioxide - are rising to the surface as the Arctic region heats up, according to preliminary findings.

Researchers found massive stores of sub-sea methane in several areas across thousands of square miles of the Siberian continental shelf and observed the gas bubbling up from the sea floor through 'chimneys', according to newspaper reports.

Researchers believe the Arctic Ocean seabed is thawing in patches and releasing greenhouse gases

The researchers believe escaping sub-sea methane is connected to rises in temperatures in the Arctic region.

One of the expedition leaders, Orjan Gustafsson, of Stockholm University in Sweden, said researchers had found 'an extensive area of intense methane release'.

'At earlier sites we had found elevated levels of dissolved methane. Yesterday, for the first time, we documented a field where the release was so intense that the methane did not have time to dissolve into the seawater but was rising as methane bubbles to the sea surface.



'These "methane chimneys" were documented on echo sounder and with seismic (instruments),' he said in an email from a Russian research ship, quoted in The Independent.

The email continued: 'The conventional thought has been that the permafrost "lid" on the sub-sea sediments on the Siberian shelf should cap and hold the massive reservoirs of shallow methane deposits in place.

'The growing evidence for release of methane in this inaccessible region may suggest that the permafrost lid is starting to get perforated and thus leak methane... The permafrost now has small holes.

'We have found elevated levels of methane above the water surface and even more in the water just below. It is obvious that the source is the seabed.'

The average temperature of the region has risen by 4C over recent decades,leading to a major decline in the area of the Arctic Ocean covered by summer sea ice.