Quantifying uncertainties of permafrost carbon–climate feedbacks

• Published in: Biogeosciences
• Main Authors: Burke, Eleanor J., Ekici, Altug, Huang, Ye, Chadburn, Sarah E., Huntingford, Chris, Ciais, Philippe, Friedlingstein, Pierre, Peng, Shushi, Krinner, Gerhard
• Other Authors: Met Office Hadley Centre for Climate Change (MOHC), United Kingdom Met Office Exeter, University of Exeter, Bjerknes Centre for Climate Research (BCCR), Department of Biological Sciences Bergen (BIO / UiB), University of Bergen (UiB)-University of Bergen (UiB), Laboratoire des Sciences du Climat et de l'Environnement Gif-sur-Yvette (LSCE), Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ), University of Leeds, Centre for Ecology and Hydrology Wallingford (CEH), Natural Environment Research Council (NERC), ICOS-ATC (ICOS-ATC), Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ), Exeter Climate Systems, College of Engineering, Mathematics and Physical Science, University of Exeter, Exeter, United Kingdom, Sino-French Institute for Earth System Science, College of Urban and Environmental Sciences, Peking University Beijing, Université Grenoble Alpes 2016-2019 (UGA 2016-2019 ), Institut des Géosciences de l’Environnement (IGE), Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut de Recherche pour le Développement (IRD)-Université Grenoble Alpes 2016-2019 (UGA 2016-2019 )
• Format: Article in Journal/Newspaper
• Language: English
• Published: HAL CCSD 2017
• Subjects: [SDU.OCEAN]Sciences of the Universe [physics]/Ocean; Atmosphere; [SDU.ENVI]Sciences of the Universe [physics]/Continental interfaces; environment; Jules; permafrost
• Online Access: https://hal.archives-ouvertes.fr/hal-01584121; https://hal.archives-ouvertes.fr/hal-01584121/document; https://hal.archives-ouvertes.fr/hal-01584121/file/bg-14-3051-2017.pdf; https://doi.org/10.5194/bg-14-3051-2017

International audience The land surface models JULES (Joint UK Land Environment Simulator, two versions) and ORCHIDEE-MICT (Organizing Carbon and Hydrology in Dynamic Ecosystems), each with a revised representation of per-mafrost carbon, were coupled to the Integrated Model Of Global Effects of climatic aNomalies (IMOGEN) intermediate-complexity climate and ocean carbon uptake model. IMOGEN calculates atmospheric carbon dioxide (CO 2) and local monthly surface climate for a given emission scenario with the land-atmosphere CO 2 flux exchange from either JULES or ORCHIDEE-MICT. These simulations include feedbacks associated with permafrost carbon changes in a warming world. Both IMOGEN-JULES and IMOGEN-ORCHIDEE-MICT were forced by historical and three alternative future-CO 2-emission scenarios. Those simulations were performed for different climate sensitivities and regional climate change patterns based on 22 different Earth system models (ESMs) used for CMIP3 (phase 3 of the Coupled Model Intercomparison Project), allowing us to explore climate uncertainties in the context of permafrost carbon-climate feedbacks. Three future emission scenarios consistent with three representative concentration pathways were used: RCP2.6, RCP4.5 and RCP8.5. Paired simulations with and without frozen carbon processes were required to quantify the impact of the permafrost carbon feedback on climate change. The additional warming from the permafrost carbon feedback is between 0.2 and 12 % of the change in the global mean temperature (T) by the year 2100 and 0.5 and 17 % of T by 2300, with these ranges reflecting differences in land surface models, climate models and emissions pathway. As a percentage of T , the permafrost carbon feedback has a greater impact on the low-emissions scenario (RCP2.6) than on the higher-emissions scenarios, suggesting that per-mafrost carbon should be taken into account when evaluating scenarios of heavy mitigation and stabilization. Structural differences between the land surface models (particu-larly ...