Articles | Volume 11, issue 15
Biogeosciences, 11, 4271–4288, 2014
Biogeosciences, 11, 4271–4288, 2014
Research article
14 Aug 2014
Research article | 14 Aug 2014

Carbon cycle uncertainty in the Alaskan Arctic

J. B. Fisher1, M. Sikka1, W. C. Oechel2, D. N. Huntzinger3, J. R. Melton4, C. D. Koven5, A. Ahlström6, M. A. Arain7, I. Baker8, J. M. Chen9, P. Ciais10, C. Davidson11, M. Dietze12, B. El-Masri13, D. Hayes14, C. Huntingford15, A. K. Jain13, P. E. Levy16, M. R. Lomas17, B. Poulter10, D. Price18, A. K. Sahoo19, K. Schaefer20, H. Tian21, E. Tomelleri22, H. Verbeeck23, N. Viovy10, R. Wania24, N. Zeng25, and C. E. Miller1 J. B. Fisher et al.
  • 1Jet Propulsion Laboratory, California Institute of Technology, 4800 Oak Grove Drive, Pasadena, CA, 91109, USA
  • 2Global Change Research Group, Department of Biology, San Diego State University, San Diego, CA, 92182, USA and the Department of Environment, Earth, and Ecosystems, The Open University, Milton Keynes, UK
  • 3School of Earth Sciences & Environmental Sustainability, Northern Arizona University, P.O. Box 5694, Flagstaff, AZ, 86011, USA
  • 4Canadian Centre for Climate Modelling and Analysis, Environment Canada, Victoria, BC, V8W 2Y2, Canada
  • 5Earth Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA, 94708, USA
  • 6Department of Physical Geography and Ecosystem Science, Lund University, Sölvegatan 12, 223 62, Lund, Sweden
  • 7School of Geography & Earth Sciences and McMaster Centre for Climate Change, McMaster University, Hamilton, ON, Canada
  • 8Atmospheric Science Department, Colorado State University, Fort Collins, CO, 80523-1371, USA
  • 9Department of Geography, University of Toronto, 100 St. George Street, Toronto, Ontario, M5S 3G3, Canada
  • 10Laboratoire des Sciences du Climat et l'Environnement, Orme des Merisiers, bat. 701 – Point courier 129, 91191 Gif Sur Yvette, France
  • 11Program in Ecology, Evolution, and Conservation Biology, University of Illinois at Urbana-Champaign, 505 S. Goodwin Ave, Urbana, IL, 61801, USA
  • 12Department of Earth and the Environment, Boston University, 675 Commonwealth Ave, Boston, MA, 02215, USA
  • 13Department of Atmospheric Sciences, University of Illinois, Urbana, IL, 61801, USA
  • 14Climate Change Science Institute and Environmental Sciences Division, Oak Ridge National Laboratory, Oak Ridge, TN, 37831-6301, USA
  • 15Centre for Ecology and Hydrology, Benson Lane, Wallingford, OX10 8BB, UK
  • 16Centre for Ecology and Hydrology, Penicuik, Midlothian, EH26 0QB, UK
  • 17Centre for Terrestrial Carbon Dynamics, University of Sheffield, Dept. of Animal & Plant Sciences, Western Bank, Sheffield, S10 2TN, UK
  • 18Natural Resources Canada, Northern Forestry Centre, 5320 – 122 Street Northwest, Edmonton, Alberta, T6H 3S5, Canada
  • 19Department of Civil and Environmental Engineering, Princeton University, Princeton, New Jersey, 08544, USA
  • 20National Snow and Ice Data Center, Cooperative Institute for Research in Environmental Sciences, University of Colorado at Boulder, Boulder, CO, 80309, USA
  • 21School of Forestry and Wildlife Sciences, Auburn University, 602 Duncan Drive, Auburn, AL, 36849, USA
  • 22Biogeochemical Model-Data Integration Group, Max Planck Institute for Biogeochemistry, Hans-Knöll-Str. 10, 07745, Jena, Germany
  • 23Laboratory of Plant Ecology, Faculty of Bioscience Engineering, Ghent University, Coupure Links 653, 9000 Ghent, Belgium
  • 24Institut des Sciences de l'Evolution (UMR5554, CNRS), Université Montpellier 2, Place Eugène Bataillon, 34090 Montpellier, France
  • 25Department of Atmospheric and Oceanic Science, University of Maryland, 2417 Computer and Space Sciences Building, College Park, MD, 20742-2425, USA

Abstract. 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 CH4 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 CH4 flux (2.52 ± 4.02 g CH4 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 Arctic 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 baseline 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.

Final-revised paper