Weakening cooling effect of northern peatlands on the global climate system during the 21st century

<p>Northern peatlands store large amounts of C. Model projected fate of the C stock has significant uncertainties due to the insufficient processes of N cycle in current peatland biogeochemistry models. In this study, we incorporate adequate N cycling processes to a Peatland Terrestrial Ecosystem Model (PTEM) to simulate C and N dynamics of northern peatlands during 15ka BP-2100. We estimate that by 1990, northern peatlands accumulate 408 Pg C and 7.8 Pg N since their initiation and their greenhouse gas emissions of CO2, CH4 and N2O have a radiative forcing (RF) of -0.57 W∙m<sup>-2</sup>. During the 21<sup>st</sup> century, mineral N content in northern peatlands will increase, resulting in more net primary productivity. With increasing greenhouse gas emissions, the cooling effect of northern peatlands is weakening under warming conditions, primarily due to increasing CH<sub>4</sub> emissions.</p>