Rapid Arctic thawing could be economic timebomb scientists say

The Guardian has a look at a new report on the cost of unfreezing the arctic - Rapid Arctic thawing could be economic timebomb, scientists say.

Rapid thawing of the Arctic could trigger a catastrophic "economic timebomb" which would cost trillions of dollars and undermine the global financial system, say a group of economists and polar scientists.

Governments and industry have expected the widespread warming of the Arctic region in the past 20 years to be an economic boon, allowing the exploitation of new gas and oilfields and enabling shipping to travel faster between Europe and Asia. But the release of a single giant "pulse" of methane from thawing Arctic permafrost beneath the East Siberian sea "could come with a $60tn [£39tn] global price tag", according to the researchers who have for the first time quantified the effects on the global economy.

Even the slow emission of a much smaller proportion of the vast quantities of methane locked up in the Arctic permafrost and offshore waters could trigger catastrophic climate change and "steep" economic losses, they say.

The Arctic sea ice, which largely melts and reforms each year, is declining at an unprecedented rate. In 2012, it collapsed to under 3.5m sqkm by mid September, just 40% of its usual extent in the 1970s. Because the ice is also losing its thickness, some scientists expect the Arctic ocean to be largely free of summer ice by 2020.

The growing fear is that as the ice retreats, the warming of the sea water will allow offshore permafrost to release ever greater quantities of methane. A giant reservoir of the greenhouse gas, in the form of gas hydrates on the East Siberian Arctic Shelf (ESAS), could be emitted, either slowly over 50 years or catastrophically fast over a shorter time frame, say the researchers.