References

Biogeosciences

1726-4189

Copernicus Publications

Göttingen, Germany

10.5194/bg-11-4271-2014

Carbon cycle uncertainty in the Alaskan Arctic

Fisher

J. B.

¹ Sikka

¹ Oechel

W. C.

https://orcid.org/0000-0002-3504-026X

² Huntzinger

D. N.

³ Melton

J. R.

https://orcid.org/0000-0002-9414-064X

⁴ Koven

C. D.

⁵ Ahlström

⁶ Arain

M. A.

⁷ Baker

⁸ Chen

J. M.

https://orcid.org/0000-0002-8682-1293

⁹ Ciais

¹⁰ Davidson

¹¹ Dietze

¹² El-Masri

¹³ Hayes

¹⁴ Huntingford

¹⁵ Jain

A. K.

https://orcid.org/0000-0002-4051-3228

¹³ Levy

P. E.

https://orcid.org/0000-0002-8505-1901

¹⁶ Lomas

M. R.

¹⁷ Poulter

https://orcid.org/0000-0002-9493-8600

¹⁰ Price

¹⁸ Sahoo

A. K.

¹⁹ Schaefer

²⁰ Tian

https://orcid.org/0000-0002-1806-4091

²¹ Tomelleri

²² Verbeeck

https://orcid.org/0000-0003-1490-0168

²³ Viovy

https://orcid.org/0000-0002-9197-6417

¹⁰ Wania

²⁴ Zeng

https://orcid.org/0000-0002-7489-7629

²⁵ Miller

C. E.

Jet Propulsion Laboratory, California Institute of Technology, 4800 Oak Grove Drive, Pasadena, CA, 91109, USA

Global 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

School of Earth Sciences & Environmental Sustainability, Northern Arizona University, P.O. Box 5694, Flagstaff, AZ, 86011, USA

Canadian Centre for Climate Modelling and Analysis, Environment Canada, Victoria, BC, V8W 2Y2, Canada

Earth Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA, 94708, USA

Department of Physical Geography and Ecosystem Science, Lund University, Sölvegatan 12, 223 62, Lund, Sweden

School of Geography & Earth Sciences and McMaster Centre for Climate Change, McMaster University, Hamilton, ON, Canada

Atmospheric Science Department, Colorado State University, Fort Collins, CO, 80523-1371, USA

Department of Geography, University of Toronto, 100 St. George Street, Toronto, Ontario, M5S 3G3, Canada

Laboratoire des Sciences du Climat et l'Environnement, Orme des Merisiers, bat. 701 – Point courier 129, 91191 Gif Sur Yvette, France

Program in Ecology, Evolution, and Conservation Biology, University of Illinois at Urbana-Champaign, 505 S. Goodwin Ave, Urbana, IL, 61801, USA

Department of Earth and the Environment, Boston University, 675 Commonwealth Ave, Boston, MA, 02215, USA

Department of Atmospheric Sciences, University of Illinois, Urbana, IL, 61801, USA

Climate Change Science Institute and Environmental Sciences Division, Oak Ridge National Laboratory, Oak Ridge, TN, 37831-6301, USA

Centre for Ecology and Hydrology, Benson Lane, Wallingford, OX10 8BB, UK

Centre for Ecology and Hydrology, Penicuik, Midlothian, EH26 0QB, UK

Centre for Terrestrial Carbon Dynamics, University of Sheffield, Dept. of Animal & Plant Sciences, Western Bank, Sheffield, S10 2TN, UK

Natural Resources Canada, Northern Forestry Centre, 5320 – 122 Street Northwest, Edmonton, Alberta, T6H 3S5, Canada

Department of Civil and Environmental Engineering, Princeton University, Princeton, New Jersey, 08544, USA

National Snow and Ice Data Center, Cooperative Institute for Research in Environmental Sciences, University of Colorado at Boulder, Boulder, CO, 80309, USA

School of Forestry and Wildlife Sciences, Auburn University, 602 Duncan Drive, Auburn, AL, 36849, USA

Biogeochemical Model-Data Integration Group, Max Planck Institute for Biogeochemistry, Hans-Knöll-Str. 10, 07745, Jena, Germany

Laboratory of Plant Ecology, Faculty of Bioscience Engineering, Ghent University, Coupure Links 653, 9000 Ghent, Belgium

Institut des Sciences de l'Evolution (UMR5554, CNRS), Université Montpellier 2, Place Eugène Bataillon, 34090 Montpellier, France

Department of Atmospheric and Oceanic Science, University of Maryland, 2417 Computer and Space Sciences Building, College Park, MD, 20742-2425, USA

14 08 2014

11 15 4271 4288

2014

This work is licensed under the Creative Commons Attribution 3.0 Unported License. To view a copy of this licence, visit https://creativecommons.org/licenses/by/3.0/

This article is available from https://bg.copernicus.org/articles/11/4271/2014/bg-11-4271-2014.html

The full text article is available as a PDF file from https://bg.copernicus.org/articles/11/4271/2014/bg-11-4271-2014.pdf

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.

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