Scientists have talked for years about the potentially devastating release of millions of tons of underground stores of methane into the atmosphere as the Arctic region becomes warmer.  Apparently, it has begun.

The Independent UK is reporting that this year's melting in the Arctic has caused the release of millions of tons of methane.  The gas, which is 20 times more damaging than carbon dioxide, is bubbling to the surface as the ice retreats and the Arctic region becomes warmer.

The Arctic region as a whole has seen a dramatic decline in the area of the Arctic Ocean covered by summer ice and a 4C rise is average temperatures.  Because the open ocean soaks up more heat from the sun than ice does, many scientists are concerned that the warming trend will be accelerated. 

Dr. Igor Semiletov of the Far-Eastern branch of the Russian Academy of Sciences has led 10 expeditions in the Laptev Sea since 1994.  He did not detect any elevated levels of methane until 2003 when he reported a rising number of methane "hotspots".  "Dr Semiletov has suggested several possible reasons why methane is now being released from the Arctic, including the rising volume of relatively warmer water being discharged from Siberia's rivers due to the melting of the permafrost on the land."

Scientists believe that the sub-sea layer of permafrost has acted like a "lid" to prevent the gas from escaping but has now melted away, allowing the methane to rise from underground deposits formed before the last ice age.

Many scientists fear that the release of the methane from under the Siberian permafrost could itself accelerate global warming, causing "a giant positive feedback where more atmospheric methane causes higher temperatures, leading to further permafrost melting and the release of yet more methane".

"The amount of methane stored beneath the Arctic is calculated to be greater than the total amount of carbon locked up in global coal reserves so there is intense interest in the stability of these deposits as the region warms at a faster rate than other places on earth."

The preliminary findings of the International Siberian Shelf Study 2008, authored by Semiletov, are being prepared for publication by the American Geophysical Union.