University of Oulu

Pedron, S. A., Jespersen, R. G., Xu, X., Khazindar, Y., Welker, J. M., & Czimczik, C. I. (2023). More snow accelerates legacy carbon emissions from Arctic permafrost. AGU Advances, 4, e2023AV000942.

More snow accelerates legacy carbon emissions from Arctic permafrost

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Author: Pedron, S. A.1; Jespersen, R. G.2; Xu, X.1;
Organizations: 1Department of Earth System Science, University of California, Irvine, CA, USA
2Department of Biological Sciences, University of Alaska, Anchorage, AK, USA
3Ecology and Genetics Research Unit, University of Oulu, Oulu, Finland
4UArctic, Rovaniemi, Finland
Format: article
Version: published version
Access: open
Online Access: PDF Full Text (PDF, 0.9 MB)
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Language: English
Published: American Geophysical Union, 2023
Publish Date: 2023-10-05


Snow is critically important to the energy budget, biogeochemistry, ecology, and people of the Arctic. While climate change continues to shorten the duration of the snow cover period, snow mass (the depth of the snow pack) has been increasing in many parts of the Arctic. Previous work has shown that deeper snow can rapidly thaw permafrost and expose the large amounts of ancient (legacy) organic matter contained within it to microbial decomposition. This process releases carbonaceous greenhouse gases but also nutrients, which promote plant growth and carbon sequestration. The net effect of increased snow depth on greenhouse gas emissions from Arctic ecosystems remains uncertain. Here we show that 25 years of snow addition turned tussock tundra, one of the most spatially extensive Arctic ecosystems, into a year-round source of ancient carbon dioxide. More snow quadrupled the amount of organic matter available to microbial decomposition, much of it previously preserved in permafrost, due to deeper seasonal thaw, soil compaction and subsidence as well as the proliferation of deciduous shrubs that lead to 10% greater carbon uptake during the growing season. However, more snow also sustained warmer soil temperatures, causing greater carbon loss during winter (+200% from October to May) and year-round. We find that increasing snow mass will accelerate the ongoing transformation of Arctic ecosystems and cause earlier-than-expected losses of climate-warming legacy carbon from permafrost.

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Series: AGU advances
ISSN: 2576-604X
ISSN-E: 2576-604X
ISSN-L: 2576-604X
Volume: 4
Issue: 4
Article number: e2023AV000942
DOI: 10.1029/2023AV000942
Type of Publication: A1 Journal article – refereed
Field of Science: 1181 Ecology, evolutionary biology
1172 Environmental sciences
Funding: This work was supported by the U.S. National Science Foundation (OPP 1649664 to C.I.C. and OPP 1836873, 1650084, 1504141, 1433063, 0856728, 0612534, 0632184, 9617643, 9321730 to J.M.W.). Snow and meteorological datasets were provided by the Toolik Field Station Environmental Data Center (OPP 1623461).
Copyright information: © 2023. The Authors. This is an open access article under the terms of the Creative Commons Attribution-NonCommercial-NoDerivs License, which permits use and distribution in any medium, provided the original work is properly cited, the use is non-commercial and no modifications or adaptations are made.