Warming response of peatland CO₂ sink is sensitive to seasonality in warming trends

Abstract

Peatlands have acted as net CO₂ sinks over millennia, exerting a global climate cooling effect. Rapid warming at northern latitudes, where peatlands are abundant, can disturb their CO₂ sink function. Here we show that sensitivity of peatland net CO₂ exchange to warming changes in sign and magnitude across seasons, resulting in complex net CO₂ sink responses. We use multiannual net CO₂ exchange observations from 20 northern peatlands to show that warmer early summers are linked to increased net CO₂ uptake, while warmer late summers lead to decreased net CO₂ uptake. Thus, net CO₂ sinks of peatlands in regions experiencing early summer warming, such as central Siberia, are more likely to persist under warmer climate conditions than are those in other regions. Our results will be useful to improve the design of future warming experiments and to better interpret large-scale trends in peatland net CO₂ uptake over the coming few decades.

Citation

Helbig, M.; Živković, T.; Alekseychik, P.; Aurela, M.; El-Madany, T.S.; Euskirchen, E.S.; Flanagan, L.B.; Griffis, T.J.; Hanson, P.J.; Hattakka, J.; Helfter, C.; Hirano, T.; Humphreys, E.R.; Kiely, G.; Kolka, R.K.; Laurila, T.; Leahy, P.G.; Lohila, A.; Mammarella, I.; Nilsson, M.B.; Panov, A.; Parmentier, F.J.W.; Peichl, M.; Rinne, J.; Roman, D.T.; Sonnentag, O.; Tuittila, E.-S; Ueyama, M.; Vesala, T.; Vestin, P.; Weldon, S.; Weslien, P.; Zaehle, S. 2022. Warming response of peatland CO₂ sink is sensitive to seasonality in warming trends. Nature Climate Change. 12(8): 743-749. https://doi.org/10.1038/s41558-022-01428-z.