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A constraint on historic growth in global photosynthesis due to rising CO2

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Keenan et al 2021. Nature. Constraints on historic growth. Accepted manuscript.pdfAccepted version512.31 kBAdobe PDFView/Open
Title: A constraint on historic growth in global photosynthesis due to rising CO2
Authors: Keenan, T
Luo, X
De Kauwe, MG
Medlyn, B
Prentice, IC
Stocker, B
Smith, N
Terrer, C
Wang, H
Zhang, Y
Zhou, S
Item Type: Journal Article
Abstract: The global terrestrial carbon sink is increasing1,2,3, offsetting roughly a third of anthropogenic CO2 released into the atmosphere each decade1, and thus serving to slow4 the growth of atmospheric CO2. It has been suggested that a CO2-induced long-term increase in global photosynthesis, a process known as CO2 fertilization, is responsible for a large proportion of the current terrestrial carbon sink4,5,6,7. The estimated magnitude of the historic increase in photosynthesis as result of increasing atmospheric CO2 concentrations, however, differs by an order of magnitude between long-term proxies and terrestrial biosphere models7,8,9,10,11,12,13. Here we quantify the historic effect of CO2 on global photosynthesis by identifying an emergent constraint14,15,16 that combines terrestrial biosphere models with global carbon budget estimates. Our analysis suggests that CO2 fertilization increased global annual photosynthesis by 11.85 ± 1.4%, or 13.98 ± 1.63 petagrams carbon (mean ± 95% confidence interval) between 1981 and 2020. Our results help resolve conflicting estimates of the historic sensitivity of global photosynthesis to CO2, and highlight the large impact anthropogenic emissions have had on ecosystems worldwide.
Issue Date: 8-Dec-2021
Date of Acceptance: 5-Oct-2021
URI: http://hdl.handle.net/10044/1/92603
DOI: 10.1038/s41586-021-04096-9
ISSN: 0028-0836
Publisher: Nature Research
Start Page: 253
End Page: 258
Journal / Book Title: Nature
Volume: 600
Copyright Statement: © The Author(s), under exclusive licence to Springer Nature Limited 2021. The final publication is available at Springer via https://doi.org/10.1038/s41586-021-04096-9
Sponsor/Funder: AXA Research Fund
Commission of the European Communities
Funder's Grant Number: AXA Chair Programme in Biosphere and Climate Impacts
Keywords: General Science & Technology
Publication Status: Published
Online Publication Date: 2021-12-08
Appears in Collections:Grantham Institute for Climate Change
Faculty of Natural Sciences