Plumes of methane -- a greenhouse gas 20 times more potent than carbon dioxide -- have been seen bubbling to the surface of the Arctic Ocean by scientists undertaking an extensive survey of the region.

The scale and volume of the gas has amazed the head of the Russian research team who has been surveying the seabed of the East Siberian Arctic Shelf.

Igor Semiletov, of the Russian Academy of Sciences, said that he has never before witnessed the scale and force of the methane being released from beneath the Arctic seabed.

Scientists estimate that there are hundreds of millions of tonnes of methane gas locked away beneath the Arctic permafrost. One of the greatest fears is that with the disappearance of the Arctic sea ice in summer, and rapidly rising temperatures across the entire region, the trapped methane could be suddenly released into the atmosphere, leading to rapid and severe climate change.

Russian research vessel Academician Lavrentiev conducted a survey of 10,000 square miles of sea. Scientists deployed instruments to monitor "fountains" or plumes of methane bubbles rising to the surface from beneath the seabed.

"In less than 10,000 square miles, we have counted more than 100 fountains, or torch-like structures, bubbling through the water column and injected directly into the atmosphere from the seabed," Dr Semiletov said. (© Independent News Service)