The Methane Monster Roars - Arctic: Loss of Permafrost is allowing Methane out

http://truth-out.org/news/item/28490-the-methane-monster-roars

Vast amounts of methane lie frozen in the Arctic. It's not news that the Arctic sea ice is melting rapidly, and that it will likely be gone for short periods during the summers starting as early as next year. Losing that ice means releasing larger amounts of previously trapped methane into the atmosphere.
Additionally, lying along the Arctic's subsea continental margins and beneath Arctic permafrost are methane hydrates, often described as methane gas surrounded by ice. In March 2010, a report in Science indicated that these cumulatively contain the equivalent of 1,000 to 10,000 gigatons of carbon.
For perspective, humans have released approximately 1,475 gigatons in total carbon dioxide since the year 1850.

"What happens in the Arctic does not stay in the Arctic."

Beckwith warns that losing the Arctic sea ice will create a state that "will represent a very different planet, with a much higher global average temperature, in which snow and ice in the northern hemisphere becomes very rare or even vanishes year round."
In the simplest terms, here's what an ice-free Arctic would mean when it comes to heating the planet: Minus the reflective ice cover on Arctic waters, solar radiation would be absorbed, not reflected, by the Arctic Ocean. That would heat those waters, and hence the planet, further. This effect has the potential to change global weather patterns, vary the flow of winds and even someday possibly alter the position of the jet stream. Polar jet streams are fast-flowing rivers of wind positioned high in the earth's atmosphere that push cold and warm air masses around, playing a critical role in determining the weather of our planet.