A recent article in Nature assumes that the "costs of a melting Artic will be huge, because the region is pivotal to the function of earth's systems, such as oceans and the climate."

Scientists and economists said that the release of the methane, trapped for thousands of years beneath the frozen permafrost of the Arctic, is one of the most dangerous "feedback" consequences of the rapid warming of the region, a process which has seen sea ice diminish by more than a third since the 1970s.

"We are looking at a big effect, possibly a catastrophic effect on global climate that has been a consequence of the extremely fast sea-ice retreat we've seen in recent years," Professor Wadhams said, of Cambridge University, who was part of the study team.

"We have an area of the world that used to be covered with sea ice all the year round but which is now, in the summer months, becoming ice free," he added.