Subarctic tundra soils, one of the largest land cover types in the world, can release significant quantities of the potent greenhouse gas nitrous oxide, according to a study published online in Nature Geoscience. Until now, these treeless soils were considered a negligible source of nitrous oxide.

Pertti Martikainen and colleagues measured nitrous oxide emissions in semi-frozen Eastern European peatlands located below the Arctic Circle. Vegetation-free patches of peat were found to emit quantities of nitrous oxide equivalent to emissions from agricultural and tropical soils, which are considered to be the largest terrestrial sources of nitrous oxide. Extrapolation of their field data to the whole of the Arctic suggests that the global warming potential of these bare peat-patches could amount to 4% of the global warming potential of Arctic methane emissions.

These findings suggest that it will be important to consider the amount of nitrogen stored in subarctic tundra soils when assessing their climatic impact.