Pyrogenic carbon decomposition critical to resolving fire’s role in the Earth system

Bowring, Simon P. K., Jones, Matthew W. ORCID: https://orcid.org/0000-0003-3480-7980, Ciais, Philippe, Guenet, Bertrand and Abiven, Samuel (2022) Pyrogenic carbon decomposition critical to resolving fire’s role in the Earth system. Nature Geoscience, 15 (2). pp. 135-142. ISSN 1752-0894

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Abstract

Recently identified post-fire carbon fluxes indicate that, to understand whether global fires represent a net carbon source or sink, one must consider both terrestrial carbon retention through pyrogenic carbon production and carbon losses via multiple pathways. Here these legacy source and sink pathways are quantified using a CMIP6 land surface model to estimate Earth’s fire carbon budget. Over the period 1901–2010, global pyrogenic carbon has driven an annual soil carbon accumulation of 337 TgC yr−1, offset by legacy carbon losses totalling −248 TgC yr−1. The residual of these values constrains the maximum annual pyrogenic carbon mineralization to 89 TgC yr−1 and the pyrogenic carbon mean residence time to 5,387 years, assuming a steady state. The residual is negative over forests and positive over grassland-savannahs (implying a potential sink), suggesting contrasting roles of vegetation in the fire carbon cycle. The paucity of observational constraints for representing pyrogenic carbon mineralization means that, without assuming a steady state, we are unable to determine the sign of the overall fire carbon balance. Constraining pyrogenic carbon mineralization rates, particularly over grassland-savannahs, is a critical research frontier that would enable a fuller understanding of fire’s role in the Earth system and inform attendant land use and conservation policy.

Item Type: Article
Additional Information: Funding Information: S.P.K.B. was supported by Swiss National Science Foundation (SNSF) grant no. SNSF 649 200021–178768 and would like to thank C. Yue, J. Chang and R. Lauerwald for discussions relating to ORCHIDEE modifications. M.W.J. was supported by the European Commission Horizon 2020 project VERIFY (grant no. 776810). P.C. was co-funded by the European Space Agency Climate Change Initiative ESA-CCI RECCAP2 project 1190 (ESRIN/ 4000123002/18/I-NB).
Uncontrolled Keywords: earth and planetary sciences(all),sdg 15 - life on land ,/dk/atira/pure/subjectarea/asjc/1900
Faculty \ School: Faculty of Science > School of Environmental Sciences
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Depositing User: LivePure Connector
Date Deposited: 16 Feb 2022 12:30
Last Modified: 23 Oct 2022 03:33
URI: https://ueaeprints.uea.ac.uk/id/eprint/83520
DOI: 10.1038/s41561-021-00892-0

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