Nature Geosci. doi: 10.1038/ngeo331 (2008)

If Earth were suddenly to warm by 4 °C, peatlands would lose 40% of the soil organic carbon from their shallow parts and 86% from their deep parts over about 700 years. Takeshi Ise of the Japan Agency for Marine-Earth Science and Technology in Yokohama and his colleagues make this prediction after building a model that incorporates peat chemistry, soil hydrology and, for the first time, thermal dynamics.

Peat is subject to positive feedback. The more it rains, the higher the water table, and the more oxygen-depleted the peat becomes, which lowers the decomposition rates of soil organic carbon. And the more soil organic carbon peat has, the better it retains water. Raising the temperature increases decomposition rates, so causing this feedback loop to run in reverse.