Fast response of cold ice-rich permafrost in northeast Siberia to a warming climate

• Published in: Nature Communications
• Main Authors: Nitzbon, Jan, Westermann, Sebastian, Langer, Moritz, Martin, Léo C.P., Strauss, Jens, Laboor, Sebastian, Boike, Julia
• Other Authors: Alfred Wegener Institute, Helmholtz Centre for Polar and Marine Research, Partenaires INRAE, Humboldt-Universität zu Berlin = Humboldt University of Berlin = Université Humboldt de Berlin (HU Berlin), University of Oslo (UiO), Department of Geosciences Oslo, Faculty of Mathematics and Natural Sciences Oslo, University of Oslo (UiO)-University of Oslo (UiO), Alfred Wegener Institute Potsdam, Alfred-Wegener-Institut, Helmholtz-Zentrum für Polar- und Meeresforschung = Alfred Wegener Institute for Polar and Marine Research = Institut Alfred-Wegener pour la recherche polaire et marine (AWI), Helmholtz-Gemeinschaft = Helmholtz Association-Helmholtz-Gemeinschaft = Helmholtz Association
• Format: Article in Journal/Newspaper
• Language: English
• Published: HAL CCSD 2020
• Subjects: [SDU.STU]Sciences of the Universe [physics]/Earth Sciences; Arctic; Climate change; Ice; permafrost; Thermokarst; Siberia
• Online Access: https://hal.science/hal-03967447; https://hal.science/hal-03967447/document; https://hal.science/hal-03967447/file/s41467-020-15725-8.pdf; https://doi.org/10.1038/s41467-020-15725-8

The ice-and organic-rich permafrost of the northeast Siberian Arctic lowlands (NESAL) has been projected to remain stable beyond 2100, even under pessimistic climate warming scenarios. However, the numerical models used for these projections lack processes which induce widespread landscape change termed thermokarst, precluding realistic simulation of permafrost thaw in such ice-rich terrain. Here, we consider thermokarst-inducing processes in a numerical model and show that substantial permafrost degradation, involving widespread landscape collapse, is projected for the NESAL under strong warming (RCP8.5), while thawing is moderated by stabilizing feedbacks under moderate warming (RCP4.5). We estimate that by 2100 thaw-affected carbon could be up to threefold (twelve-fold) under RCP4.5 (RCP8.5), of what is projected if thermokarst-inducing processes are ignored. Our study provides progress towards robust assessments of the global permafrost carbon-climate feedback by Earth system models, and underlines the importance of mitigating climate change to limit its impacts on permafrost ecosystems.