Methane is moving from thawing Arctic soils into lakes and could be released into the atmosphere. Methane is a potent greenhouse gas, so this mechanism might exacerbate future Arctic warming.

A team led by Adina Paytan of the University of California, Santa Cruz, found that levels of methane were higher in soils around Toolik Lake, Alaska, than in the lake water itself. Geochemical measurements suggested that the methane is transported from the soil's active layer, which freezes and thaws every year, into the lake and then into the atmosphere.

If that pattern holds true for other northern lakes, soil could have a bigger role in sending methane into Arctic air than previously thought.

Proc. Natl Acad. Sci. USA http://doi.org/2sh (2015)