Peatlands Have the Potential to Emerge as Significant Contributors to Future Climate Warming

Abstract Peatlands are huge reservoirs of carbon in the terrestrial ecosystem. They are both long-term sinks of organic carbon and a major natural source of atmospheric methane. These carbon-rich ecosystems are at risk of losing their carbon sink capacity and becoming a huge source of carbon dioxide and methane due to ongoing warming. In this study, we examined the past and future trends of peatland carbon and methane fluxes and their influence on the climate system. We found that peatlands > 25 °N will remain a carbon sink and methane source under a low-warming scenario (RCP2.6) but they would shift from being not only a source of methane but also of carbon dioxide under a high-warming scenario (RCP8.5) by the mid-21st century leading to a strong radiative forcing (0.25 W m-2) by the end of the 23rd century. This underlines the potential warming feedback in which peatland radiative forcing on the climate system would shift from negative to positive in the future.