Carbon cycle uncertainty in the Alaskan Arctic

• Published in: Biogeosciences
• Main Authors: Fisher, J., Sikka, M., Oechel, W., Huntzinger, D., Melton, J., Koven, C., Ahlström, A., Arain, M., Baker, I., Chen, J., Ciais, P., Davidson, C., Dietze, M., El-Masri, B., Hayes, D., Huntingford, C., Jain, A., Levy, P., Lomas, M.R., Poulter, B., Price, D., Sahoo, A., Schaefer, K., Tian, H., Tomelleri, E., Verbeeck, H., Viovy, N., Wania, R., Zeng, N., Miller, C.
• Other Authors: Jet Propulsion Laboratory (JPL), NASA-California Institute of Technology (CALTECH), San Diego State University (SDSU), Northern Arizona University Flagstaff, Canadian Centre for Climate Modelling and Analysis (CCCma), Environment and Climate Change Canada, Lawrence Berkeley National Laboratory Berkeley (LBNL), Lund University Lund, McMaster University Hamilton, Ontario, Colorado State University Fort Collins (CSU), Department of Geography and Planning University of Toronto, University of Toronto, Laboratoire des Sciences du Climat et de l'Environnement Gif-sur-Yvette (LSCE), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), ICOS-ATC (ICOS-ATC), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), University of Illinois at Urbana-Champaign Urbana, University of Illinois System, Boston University Boston (BU), Oak Ridge National Laboratory Oak Ridge (ORNL), UT-Battelle, LLC, Centre for Ecology and Hydrology Wallingford (CEH), Natural Environment Research Council (NERC), Centre for Ecology and Hydrology (CEH), University of Sheffield Sheffield, Montana State University (MSU), Natural Resources Canada (NRCan), Princeton University, National Snow and Ice Data Center (NSIDC), University of Colorado Boulder, Auburn University (AU), Max Planck Institute for Biogeochemistry (MPI-BGC), Max-Planck-Gesellschaft, Universiteit Gent = Ghent University Belgium (UGENT), Modélisation des Surfaces et Interfaces Continentales (MOSAIC), Institut des Sciences de l'Evolution de Montpellier (UMR ISEM), Centre de Coopération Internationale en Recherche Agronomique pour le Développement (Cirad)-École pratique des hautes études (EPHE), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Montpellier (UM)-Institut de recherche pour le développement IRD : UR226-Centre National de la Recherche Scientifique (CNRS), Department of Atmospheric and Oceanic Science College Park (AOSC), University of Maryland College Park, University of Maryland System-University of Maryland System
• Format: Article in Journal/Newspaper
• Language: English
• Published: HAL CCSD 2014
• Subjects: [SDU.OCEAN]Sciences of the Universe [physics]/Ocean; Atmosphere; [SDU.ENVI]Sciences of the Universe [physics]/Continental interfaces; environment; Arctic; Climate change; Alaska
• Online Access: https://hal.archives-ouvertes.fr/hal-02928016; https://hal.archives-ouvertes.fr/hal-02928016/document; https://hal.archives-ouvertes.fr/hal-02928016/file/bg-11-4271-2014.pdf; https://doi.org/10.5194/bg-11-4271-2014

International audience Climate change is leading to a disproportionately large warming in the high northern latitudes, but the magnitude and sign of the future carbon balance of the Arctic are highly uncertain. Using 40 terrestrial biosphere models for the Alaskan Arctic from four recent model intercomparison projects-NACP (North American Carbon Program) site and regional syntheses, TRENDY (Trends in net land atmosphere carbon exchanges), and WETCHIMP (Wetland and Wetland CH 4 Inter-comparison of Models Project)-we provide a baseline of terrestrial carbon cycle uncertainty, defined as the multi-model standard deviation (σ) for each quantity that follows. Mean annual absolute uncertainty was largest for soil carbon (14.0 ± 9.2 kg C m −2), then gross primary production (GPP) (0.22 ± 0.50 kg C m −2 yr −1), ecosystem respiration (Re) (0.23 ± 0.38 kg C m −2 yr −1), net primary production (NPP) (0.14 ± 0.33 kg C m −2 yr −1), autotrophic respiration (Ra) (0.09 ± 0.20 kg C m −2 yr −1), heterotrophic respiration (Rh) (0.14 ± 0.20 kg C m −2 yr −1), net ecosystem exchange (NEE) (−0.01 ± 0.19 kg C m −2 yr −1), and CH 4 flux (2.52 ± 4.02 g CH 4 m −2 yr −1). There were no consistent spatial patterns in the larger Alaskan Arctic and boreal regional carbon stocks and fluxes, with some models showing NEE for Alaska as a strong carbon sink, others as a strong carbon source, while still others as carbon neutral. Finally, AmeriFlux data are used at two sites in the Alaskan Arc-tic to evaluate the regional patterns; observed seasonal NEE was captured within multi-model uncertainty. This assessment of carbon cycle uncertainties may be used as a base-line for the improvement of experimental and modeling activities , as well as a reference for future trajectories in carbon cycling with climate change in the Alaskan Arctic and larger boreal region.