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Carbon cycle uncertainty in the Alaskan Arctic

Fisher, J. B. and Sikka, M. and Oechel, W. C. and Huntzinger, D. N. and Melton, J. R. and Koven, C. D. and Ahlström, A. and Arain, M. A. and Baker, I. and Chen, J. M. and Ciais, P. and Davidson, C. and Dietze, M. and El-Masri, B. and Hayes, D. and Huntingford, C. and Jain, A. K. and Levy, P. E. and Lomas, M. R. and Poulter, B. and Price, D. and Sahoo, A. K. and Schaefer, K. and Tian, H. and Tomelleri, E. and Verbeeck, H. and Viovy, N. and Wania, R. and Zeng, N. and Miller, C. E. (2014) Carbon cycle uncertainty in the Alaskan Arctic. Biogeosciences, 11 (15). pp. 4271-4288. ISSN 1726-4189

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Publisher’s or external URL: http://dx.doi.org/10.5194/bg-11-4271-2014


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.

Item Type: Article
Publisher’s Statement: © Author(s) 2014. This work is distributed under the Creative Commons Attribution 3.0 License.
ID number or DOI: 10.5194/bg-11-4271-2014
Keywords: atmospheric inversions; climate-change; comparison project wetchimp; global vegetation model; methane emissions; permafrost carbon; present state; terrestrial biosphere; tundra ecosystems; wetland extent
Subjects: Q Science > QC Physics
NAU Depositing Author Academic Status: Faculty/Staff
Department/Unit: College of Engineering, Forestry, and Natural Science > School of Earth Sciences and Environmental Sustainability
Date Deposited: 30 Sep 2015 19:16
URI: http://openknowledge.nau.edu/id/eprint/489

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