Heat produced by microbes that break down organic material can speed up the thawing of frozen soils in the Arctic.

Thawing permafrost in a warming Arctic could release large amounts of organic carbon into the atmosphere, enhancing global warming. Bo Elberling at the University of Copenhagen and his colleagues determined the amount of heat produced by microbial activity in permafrost soils sampled from six sites in Greenland. They found that different types of organic soil are all susceptible to ground heat production, whereas mineral soils are less prone to it.

Using a model of heat and water flow, the scientists estimate that, as increasing temperatures begin to melt the permafrost, microbial heat production will also increase, accelerating the thaw.

Nature Clim. Change http://dx.doi.org/10.1038/nclimate2590 (2015)