Martin G De Kauwe Ana Bastos Soumaya Belmecheri Katerina Georgiou Ralph F. Keeling Sean M. McMahon Belinda E. Medlyn David J P Moore Richard J. Norby Sonke Zaehle Kristina J. Anderson-Teixeira Giovanna Battipaglia Roel J W Brienen Kristine G Cabugao Maxime Cailleret Elliott Campbell Josep G Canadell Philippe Ciais Matthew E Craig David S Ellsworth Graham D Farquhar Simone Fatichi Joshua B. Fisher David C Frank Heather Graven Lianhong Gu Vanessa Haverd Kelly A Heilman Martin Heimann Bruce A Hungate Colleen M. Iverson Fortunat Joos Mingkai Jiang Trevor F. Keenan Jurgen Knauer Christian Korner Victor O Leshyk Sebastian Leuzinger Yao Liu Natasha MacBean Yadvinder Malhi Tim R McVicar Josep Penuelas Julia Pongratz A Shafer Powell Terhi Riutta Manon E B Sabot Juergen Schleucher Stephen Sitch William K. Smith Benjamin N. Sulman Benton Taylor Cesar Terrer Margaret S. Torn Kathleen K Treseder Anna T Trugman Susan E. Trumbore Phillip J. van Mantgem Steve L Voelker Mary E Whelan Peiter A Zuidema. Anthony P. Walker 2021 <p><span>Atmospheric carbon dioxide concentration ([CO</span>₂<span>]) 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 [CO</span>₂<span>] increase and thus climate change. However, ecosystem CO</span>₂<span>&nbsp;responses are complex or confounded by concurrent changes in multiple agents of global change and evidence for a [CO</span>₂<span>]‐driven terrestrial carbon sink can appear contradictory. Here we synthesize theory and broad, multidisciplinary evidence for the effects of increasing [CO</span>₂<span>] (iCO</span>₂<span>) 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 iCO</span>₂<span>&nbsp;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 iCO</span>₂<span>&nbsp;responses are high in comparison to experiments and predictions from theory. Plant mortality and soil carbon iCO</span>₂<span>&nbsp;responses are highly uncertain. In conclusion, a range of evidence supports a positive terrestrial carbon sink in response to iCO</span>₂<span>, albeit with uncertain magnitude and strong suggestion of a role for additional agents of global change.</span></p> application/pdf 10.1111/nph.16866 en New Phytologist Foundation Integrating the evidence for a terrestrial carbon sink caused by increasing atmospheric CO2 article