[{"article_processing_charge":"No","date_published":"2021-03-01T00:00:00Z","title":"Integrating the evidence for a terrestrial carbon sink caused by increasing atmospheric CO2","volume":229,"month":"03","quality_controlled":"1","date_updated":"2026-08-06T08:39:39Z","external_id":{"pmid":["32789857"]},"main_file_link":[{"open_access":"1","url":"https://doi.org/10.1111/nph.16866"}],"das_tickbox":"1","publisher":"Wiley","scopus_import":"1","citation":{"ieee":"A. P. Walker <i>et al.</i>, “Integrating the evidence for a terrestrial carbon sink caused by increasing atmospheric CO2,” <i>New Phytologist</i>, vol. 229, no. 5. Wiley, pp. 2413–2445, 2021.","ama":"Walker AP, De Kauwe MG, Bastos A, et al. Integrating the evidence for a terrestrial carbon sink caused by increasing atmospheric CO2. <i>New Phytologist</i>. 2021;229(5):2413-2445. doi:<a href=\"https://doi.org/10.1111/nph.16866\">10.1111/nph.16866</a>","apa":"Walker, A. P., De Kauwe, M. G., Bastos, A., Belmecheri, S., Georgiou, K., Keeling, R. F., … Zuidema, P. A. (2021). Integrating the evidence for a terrestrial carbon sink caused by increasing atmospheric CO2. <i>New Phytologist</i>. Wiley. <a href=\"https://doi.org/10.1111/nph.16866\">https://doi.org/10.1111/nph.16866</a>","chicago":"Walker, Anthony P., Martin G. De Kauwe, Ana Bastos, Soumaya Belmecheri, Katerina Georgiou, Ralph F. Keeling, Sean M. McMahon, et al. “Integrating the Evidence for a Terrestrial Carbon Sink Caused by Increasing Atmospheric CO2.” <i>New Phytologist</i>. Wiley, 2021. <a href=\"https://doi.org/10.1111/nph.16866\">https://doi.org/10.1111/nph.16866</a>.","mla":"Walker, Anthony P., et al. “Integrating the Evidence for a Terrestrial Carbon Sink Caused by Increasing Atmospheric CO2.” <i>New Phytologist</i>, vol. 229, no. 5, Wiley, 2021, pp. 2413–45, doi:<a href=\"https://doi.org/10.1111/nph.16866\">10.1111/nph.16866</a>.","ista":"Walker AP, De Kauwe MG, Bastos A, Belmecheri S, Georgiou K, Keeling RF, McMahon SM, Medlyn BE, Moore DJP, Norby RJ, Zaehle S, Anderson‐Teixeira KJ, Battipaglia G, Brienen RJW, Cabugao KG, Cailleret M, Campbell E, Canadell JG, Ciais P, Craig ME, Ellsworth DS, Farquhar GD, Fatichi S, Fisher JB, Frank DC, Graven H, Gu L, Haverd V, Heilman K, Heimann M, Hungate BA, Iversen CM, Joos F, Jiang M, Keenan TF, Knauer J, Körner C, Leshyk VO, Leuzinger S, Liu Y, MacBean N, Malhi Y, McVicar TR, Penuelas J, Pongratz J, Powell AS, Riutta T, Sabot MEB, Schleucher J, Sitch S, Smith WK, Sulman B, Taylor B, Terrer C, Torn MS, Treseder KK, Trugman AT, Trumbore SE, van Mantgem PJ, Voelker SL, Whelan ME, Zuidema PA. 2021. Integrating the evidence for a terrestrial carbon sink caused by increasing atmospheric CO2. New Phytologist. 229(5), 2413–2445.","short":"A.P. Walker, M.G. De Kauwe, A. Bastos, S. Belmecheri, K. Georgiou, R.F. Keeling, S.M. McMahon, B.E. Medlyn, D.J.P. Moore, R.J. Norby, S. Zaehle, K.J. Anderson‐Teixeira, G. Battipaglia, R.J.W. Brienen, K.G. Cabugao, M. Cailleret, E. Campbell, J.G. Canadell, P. Ciais, M.E. Craig, D.S. Ellsworth, G.D. Farquhar, S. Fatichi, J.B. Fisher, D.C. Frank, H. Graven, L. Gu, V. Haverd, K. Heilman, M. Heimann, B.A. Hungate, C.M. Iversen, F. Joos, M. Jiang, T.F. Keenan, J. Knauer, C. Körner, V.O. Leshyk, S. Leuzinger, Y. Liu, N. MacBean, Y. Malhi, T.R. McVicar, J. Penuelas, J. Pongratz, A.S. Powell, T. Riutta, M.E.B. Sabot, J. Schleucher, S. Sitch, W.K. Smith, B. Sulman, B. Taylor, C. Terrer, M.S. Torn, K.K. Treseder, A.T. Trugman, S.E. Trumbore, P.J. van Mantgem, S.L. Voelker, M.E. Whelan, P.A. Zuidema, New Phytologist 229 (2021) 2413–2445."},"abstract":[{"lang":"eng","text":"Atmospheric carbon dioxide concentration ([CO 2 ]) is increasing, which increases leaf-scalephotosynthesis and intrinsic water-use efficiency. These direct responses have the potential toincrease plant growth, vegetation biomass, and soil organic matter; transferring carbon from theatmosphere into terrestrial ecosystems (a carbon sink). A substantial global terrestrial carbon sinkwould slow the rate of [CO 2] increase and thus climate change. However, ecosystem CO2responses are complex or confounded by concurrent changes in multiple agents of global changeand evidence for a [CO 2]-driven terrestrial carbon sink can appear contradictory. Here wesynthesize theory and broad, multidisciplinary evidence for the effects of increasing [CO 2](iCO 2) on the global terrestrial carbon sink. Evidence suggests a substantial increase in globalphotosynthesis since pre-industrial times. Established theory, supported by experiments,indicates that iCO 2 is likely responsible for about half of the increase. Global carbon budgeting,atmospheric data, and forest inventories indicate a historical carbon sink, and these apparentiCO 2 responses are high in comparison to experiments and predictions from theory. Plantmortality and soil carbon iCO 2 responses are highly uncertain. In conclusion, a range of evidencesupports a positive terrestrial carbon sink in response to iCO2 , albeit with uncertain magnitudeand strong suggestion of a role for additional agents of global change."}],"keyword":["Beta factor","Carbon dioxide","CO2 fertilization","CO2-fertilization hypothesis","Free-air CO2 enrichment (FACE)","Global carbon cycle","Land–atmosphere feedback","Terrestrial ecosystems"],"oa_version":"Published Version","status":"public","type":"journal_article","publication_identifier":{"eissn":["1469-8137"],"issn":["0028-646X"]},"OA_type":"free access","article_type":"original","date_created":"2026-07-27T12:30:24Z","year":"2021","intvolume":"       229","publication_status":"published","extern":"1","oa":1,"doi":"10.1111/nph.16866","language":[{"iso":"eng"}],"author":[{"last_name":"Walker","first_name":"Anthony P.","full_name":"Walker, Anthony P."},{"full_name":"De Kauwe, Martin G.","first_name":"Martin G.","last_name":"De Kauwe"},{"first_name":"Ana","last_name":"Bastos","full_name":"Bastos, Ana"},{"first_name":"Soumaya","last_name":"Belmecheri","full_name":"Belmecheri, Soumaya"},{"last_name":"Georgiou","first_name":"Katerina","full_name":"Georgiou, Katerina"},{"full_name":"Keeling, Ralph F.","last_name":"Keeling","first_name":"Ralph F."},{"last_name":"McMahon","first_name":"Sean M.","full_name":"McMahon, Sean M."},{"full_name":"Medlyn, Belinda E.","first_name":"Belinda E.","last_name":"Medlyn"},{"first_name":"David J. P.","last_name":"Moore","full_name":"Moore, David J. P."},{"full_name":"Norby, Richard J.","last_name":"Norby","first_name":"Richard J."},{"full_name":"Zaehle, Sönke","last_name":"Zaehle","first_name":"Sönke"},{"full_name":"Anderson‐Teixeira, Kristina J.","last_name":"Anderson‐Teixeira","first_name":"Kristina J."},{"full_name":"Battipaglia, Giovanna","last_name":"Battipaglia","first_name":"Giovanna"},{"first_name":"Roel J. W.","last_name":"Brienen","full_name":"Brienen, Roel J. W."},{"first_name":"Kristine G.","last_name":"Cabugao","full_name":"Cabugao, Kristine G."},{"full_name":"Cailleret, Maxime","last_name":"Cailleret","first_name":"Maxime"},{"full_name":"Campbell, Elliott","first_name":"Elliott","last_name":"Campbell"},{"full_name":"Canadell, Josep G.","last_name":"Canadell","first_name":"Josep G."},{"full_name":"Ciais, Philippe","last_name":"Ciais","first_name":"Philippe"},{"full_name":"Craig, Matthew E.","first_name":"Matthew E.","last_name":"Craig"},{"full_name":"Ellsworth, David S.","first_name":"David S.","last_name":"Ellsworth"},{"full_name":"Farquhar, Graham D.","first_name":"Graham D.","last_name":"Farquhar"},{"id":"cf8e546b-a9b0-11f0-a43b-aa89ed1b56d6","full_name":"Fatichi, Simone","first_name":"Simone","last_name":"Fatichi"},{"last_name":"Fisher","first_name":"Joshua B.","full_name":"Fisher, Joshua B."},{"first_name":"David C.","last_name":"Frank","full_name":"Frank, David C."},{"last_name":"Graven","first_name":"Heather","full_name":"Graven, Heather"},{"full_name":"Gu, Lianhong","last_name":"Gu","first_name":"Lianhong"},{"full_name":"Haverd, Vanessa","first_name":"Vanessa","last_name":"Haverd"},{"last_name":"Heilman","first_name":"Kelly","full_name":"Heilman, Kelly"},{"full_name":"Heimann, Martin","first_name":"Martin","last_name":"Heimann"},{"last_name":"Hungate","first_name":"Bruce A.","full_name":"Hungate, Bruce A."},{"full_name":"Iversen, Colleen M.","first_name":"Colleen M.","last_name":"Iversen"},{"full_name":"Joos, Fortunat","last_name":"Joos","first_name":"Fortunat"},{"full_name":"Jiang, Mingkai","last_name":"Jiang","first_name":"Mingkai"},{"last_name":"Keenan","first_name":"Trevor F.","full_name":"Keenan, Trevor F."},{"last_name":"Knauer","first_name":"Jürgen","full_name":"Knauer, Jürgen"},{"first_name":"Christian","last_name":"Körner","full_name":"Körner, Christian"},{"full_name":"Leshyk, Victor O.","last_name":"Leshyk","first_name":"Victor O."},{"last_name":"Leuzinger","first_name":"Sebastian","full_name":"Leuzinger, Sebastian"},{"full_name":"Liu, Yao","first_name":"Yao","last_name":"Liu"},{"full_name":"MacBean, Natasha","last_name":"MacBean","first_name":"Natasha"},{"full_name":"Malhi, Yadvinder","last_name":"Malhi","first_name":"Yadvinder"},{"full_name":"McVicar, Tim R.","first_name":"Tim R.","last_name":"McVicar"},{"full_name":"Penuelas, Josep","last_name":"Penuelas","first_name":"Josep"},{"first_name":"Julia","last_name":"Pongratz","full_name":"Pongratz, Julia"},{"first_name":"A. Shafer","last_name":"Powell","full_name":"Powell, A. Shafer"},{"full_name":"Riutta, Terhi","last_name":"Riutta","first_name":"Terhi"},{"last_name":"Sabot","first_name":"Manon E. B.","full_name":"Sabot, Manon E. B."},{"full_name":"Schleucher, Juergen","first_name":"Juergen","last_name":"Schleucher"},{"first_name":"Stephen","last_name":"Sitch","full_name":"Sitch, Stephen"},{"full_name":"Smith, William K.","last_name":"Smith","first_name":"William K."},{"first_name":"Benjamin","last_name":"Sulman","full_name":"Sulman, Benjamin"},{"first_name":"Benton","last_name":"Taylor","full_name":"Taylor, Benton"},{"full_name":"Terrer, César","last_name":"Terrer","first_name":"César"},{"full_name":"Torn, Margaret S.","last_name":"Torn","first_name":"Margaret S."},{"full_name":"Treseder, Kathleen K.","first_name":"Kathleen K.","last_name":"Treseder"},{"full_name":"Trugman, Anna T.","last_name":"Trugman","first_name":"Anna T."},{"last_name":"Trumbore","first_name":"Susan E.","full_name":"Trumbore, Susan E."},{"first_name":"Phillip J.","last_name":"van Mantgem","full_name":"van Mantgem, Phillip J."},{"full_name":"Voelker, Steve L.","first_name":"Steve L.","last_name":"Voelker"},{"last_name":"Whelan","first_name":"Mary E.","full_name":"Whelan, Mary E."},{"full_name":"Zuidema, Pieter A.","last_name":"Zuidema","first_name":"Pieter A."}],"page":"2413-2445","pmid":1,"user_id":"ba8df636-2132-11f1-aed0-ed93e2281fdd","_id":"22570","issue":"5","publication":"New Phytologist","OA_place":"publisher","day":"01"},{"volume":113,"title":"Partitioning direct and indirect effects reveals the response of water-limited ecosystems to elevated CO","date_published":"2016-11-08T00:00:00Z","article_processing_charge":"No","external_id":{"pmid":["27791074"]},"date_updated":"2026-08-06T08:08:46Z","quality_controlled":"1","month":"11","keyword":["carbon dioxide","modeling","FACE","soil moisture","evapotranspiration"],"citation":{"ama":"Fatichi S, Leuzinger S, Paschalis A, Langley JA, Donnellan Barraclough A, Hovenden MJ. Partitioning direct and indirect effects reveals the response of water-limited ecosystems to elevated CO. <i>Proceedings of the National Academy of Sciences</i>. 2016;113(45):12757-12762. doi:<a href=\"https://doi.org/10.1073/pnas.1605036113\">10.1073/pnas.1605036113</a>","ieee":"S. Fatichi, S. Leuzinger, A. Paschalis, J. A. Langley, A. Donnellan Barraclough, and M. J. Hovenden, “Partitioning direct and indirect effects reveals the response of water-limited ecosystems to elevated CO,” <i>Proceedings of the National Academy of Sciences</i>, vol. 113, no. 45. National Academy of Sciences, pp. 12757–12762, 2016.","short":"S. Fatichi, S. Leuzinger, A. Paschalis, J.A. Langley, A. Donnellan Barraclough, M.J. Hovenden, Proceedings of the National Academy of Sciences 113 (2016) 12757–12762.","ista":"Fatichi S, Leuzinger S, Paschalis A, Langley JA, Donnellan Barraclough A, Hovenden MJ. 2016. Partitioning direct and indirect effects reveals the response of water-limited ecosystems to elevated CO. Proceedings of the National Academy of Sciences. 113(45), 12757–12762.","mla":"Fatichi, Simone, et al. “Partitioning Direct and Indirect Effects Reveals the Response of Water-Limited Ecosystems to Elevated CO.” <i>Proceedings of the National Academy of Sciences</i>, vol. 113, no. 45, National Academy of Sciences, 2016, pp. 12757–62, doi:<a href=\"https://doi.org/10.1073/pnas.1605036113\">10.1073/pnas.1605036113</a>.","chicago":"Fatichi, Simone, Sebastian Leuzinger, Athanasios Paschalis, J. Adam Langley, Alicia Donnellan Barraclough, and Mark J. Hovenden. “Partitioning Direct and Indirect Effects Reveals the Response of Water-Limited Ecosystems to Elevated CO.” <i>Proceedings of the National Academy of Sciences</i>. National Academy of Sciences, 2016. <a href=\"https://doi.org/10.1073/pnas.1605036113\">https://doi.org/10.1073/pnas.1605036113</a>.","apa":"Fatichi, S., Leuzinger, S., Paschalis, A., Langley, J. A., Donnellan Barraclough, A., &#38; Hovenden, M. J. (2016). Partitioning direct and indirect effects reveals the response of water-limited ecosystems to elevated CO. <i>Proceedings of the National Academy of Sciences</i>. National Academy of Sciences. <a href=\"https://doi.org/10.1073/pnas.1605036113\">https://doi.org/10.1073/pnas.1605036113</a>"},"scopus_import":"1","abstract":[{"lang":"eng","text":"Increasing concentrations of atmospheric carbon dioxide are expected to affect carbon assimilation and evapotranspiration (ET), ultimately driving changes in plant growth, hydrology, and the global carbon balance. Direct leaf biochemical effects have been widely investigated, whereas indirect effects, although documented, elude explicit quantification in experiments. Here, we used a mechanistic model to investigate the relative contributions of direct (through carbon assimilation) and indirect (via soil moisture savings due to stomatal closure, and changes in leaf area index) effects of elevated CO2 across a variety of ecosystems. We specifically determined which ecosystems and climatic conditions maximize the indirect effects of elevated CO2. The simulations suggest that the indirect effects of elevated CO2 on net primary productivity are large and variable, ranging from less than 10% to more than 100% of the size of direct effects. For ET, indirect effects were, on average, 65% of the size of direct effects. Indirect effects tended to be considerably larger in water-limited ecosystems. As a consequence, the total CO2 effect had a significant, inverse relationship with the wetness index and was directly related to vapor pressure deficit. These results have major implications for our understanding of the CO2 response of ecosystems and for global projections of CO2 fertilization, because, although direct effects are typically understood and easily reproducible in models, simulations of indirect effects are far more challenging and difficult to constrain. Our findings also provide an explanation for the discrepancies between experiments in the total CO2 effect on net primary productivity."}],"oa_version":"Published Version","publisher":"National Academy of Sciences","main_file_link":[{"url":"https://doi.org/10.1073/pnas.1605036113","open_access":"1"}],"das_tickbox":"1","OA_type":"free access","type":"journal_article","publication_identifier":{"eissn":["1091-6490"],"issn":["0027-8424"]},"status":"public","year":"2016","date_created":"2026-07-27T12:30:24Z","article_type":"original","language":[{"iso":"eng"}],"author":[{"last_name":"Fatichi","first_name":"Simone","id":"cf8e546b-a9b0-11f0-a43b-aa89ed1b56d6","full_name":"Fatichi, Simone"},{"first_name":"Sebastian","last_name":"Leuzinger","full_name":"Leuzinger, Sebastian"},{"first_name":"Athanasios","last_name":"Paschalis","full_name":"Paschalis, Athanasios"},{"full_name":"Langley, J. Adam","first_name":"J. Adam","last_name":"Langley"},{"first_name":"Alicia","last_name":"Donnellan Barraclough","full_name":"Donnellan Barraclough, Alicia"},{"full_name":"Hovenden, Mark J.","first_name":"Mark J.","last_name":"Hovenden"}],"oa":1,"extern":"1","publication_status":"published","doi":"10.1073/pnas.1605036113","intvolume":"       113","_id":"22536","user_id":"ba8df636-2132-11f1-aed0-ed93e2281fdd","issue":"45","pmid":1,"page":"12757-12762","day":"08","OA_place":"publisher","publication":"Proceedings of the National Academy of Sciences"}]