Alaska’s biggest tundra fire sparks climate warning
http://www.newscientist.com/ article/ dn17537-alaskas-biggest-tundra-fire-sparks-climate-warning.html

Pristine tundra takes up about 30 to 70 grams of carbon per square metre during the summer months, whereas the severely burned site lost about 40 to 120 grams per square metre. The team also found that the most severely burned terrain absorbed 71 per cent more solar radiation than normal, warming faster as a result and losing a layer of permafrost 5 to 10 centimetres deep.

“That may not seem like a lot,” says Rocha, “but over the entire fire scar you’re talking about 5 to 10 cm of water over a 1000 sq km area.” Plus there’s the double whammy of positive feedback: as tundra burns and emits carbon, it melts the permafrost – and that releases more carbon into the atmosphere. “Along with the melting ice in the permafrost, you’re also exposing more old carbon that was stored in that freezer [as organic material] and is being allowed to decompose and reintroduce itself to the atmosphere.”