Integrating the evidence for a terrestrial carbon sink caused by increasing atmospheric CO2

DOI
Publisher DOI
Abstract
Summary Atmospheric carbon dioxide concentration ([CO2]) is increasing, which increases leaf-scale photosynthesis and intrinsic water-use efficiency. These direct responses have the potential to increase plant growth, vegetation biomass, and soil organic matter; transferring carbon from the atmosphere into terrestrial ecosystems (a carbon sink). A substantial global terrestrial carbon sink would slow the rate of [CO2] increase and thus climate change. However, ecosystem CO2 responses are complex or confounded by concurrent changes in multiple agents of global change and evidence for a [CO2]-driven terrestrial carbon sink can appear contradictory. Here we synthesize theory and broad, multidisciplinary evidence for the effects of increasing [CO2] (iCO2) on the global terrestrial carbon sink. Evidence suggests a substantial increase in global photosynthesis since pre-industrial times. Established theory, supported by experiments, indicates that iCO2 is likely responsible for about half of the increase. Global carbon budgeting, atmospheric data, and forest inventories indicate a historical carbon sink, and these apparent iCO2 responses are high in comparison to experiments and predictions from theory. Plant mortality and soil carbon iCO2 responses are highly uncertain. In conclusion, a range of evidence supports a positive terrestrial carbon sink in response to iCO2, albeit with uncertain magnitude and strong suggestion of a role for additional agents of global change.
Date Issued
2021-03
Publication Type
Article
Subject(s)
Subjects
beta factor carbon dioxide CO2 fertilization CO2-fertilization hypothesis free-air CO2 enrichment (FACE) global carbon cycle land–atmosphere feedback terrestrial ecosystems
Language(s)
en
Author(s)
Walker, Anthony P.
De Kauwe, Martin G.
Bastos, Ana
Belmecheri, Soumaya
Georgiou, Katerina
Keeling, Ralph F.
McMahon, Sean M.
Medlyn, Belinda E.
Moore, David J. P.
Norby, Richard J.
Zaehle, Sönke
Anderson-Teixeira, Kristina J.
Battipaglia, Giovanna
Brienen, Roel J. W.
Cabugao, Kristine G.
Cailleret, Maxime
Campbell, Elliott
Canadell, Josep G.
Ciais, Philippe
Craig, Matthew E.
Ellsworth, David S.
Farquhar, Graham D.
Fatichi, Simone
Fisher, Joshua B.
Frank, David C.
Graven, Heather
Gu, Lianhong
Haverd, Vanessa
Heilman, Kelly
Heimann, Martin
Hungate, Bruce A.
Iversen, Colleen M.
Jiang, Mingkai
Keenan, Trevor F.
Knauer, Jürgen
Körner, Christian
Leshyk, Victor O.
Leuzinger, Sebastian
Liu, Yao
MacBean, Natasha
Malhi, Yadvinder
McVicar, Tim R.
Penuelas, Josep
Pongratz, Julia
Powell, A. Shafer
Riutta, Terhi
Sabot, Manon E. B.
Schleucher, Juergen
Sitch, Stephen
Smith, William K.
Sulman, Benjamin
Taylor, Benton
Terrer, César
Torn, Margaret S.
Treseder, Kathleen K.
Trugman, Anna T.
Trumbore, Susan E.
van Mantgem, Phillip J.
Voelker, Steve L.
Whelan, Mary E.
Zuidema, Pieter A.
Additional Credits
Journal
New Phytologist
Publisher
John Wiley & Sons, Ltd
ISSN
0028-646X
Access(Rights)
restricted
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