Abstract
The global distribution of the optimum air temperature for ecosystem-level gross primary productivity (Topteco) is poorly understood, despite its importance for ecosystem carbon uptake under future warming. We provide empirical evidence for the existence of such an optimum, using measurements of in situ eddy covariance and satellite-derived proxies, and report its global distribution. Topteco is consistently lower than the physiological optimum temperature of leaf-level photosynthetic capacity, which typically exceeds 30 °C. The global average Topteco is estimated to be 23 ± 6 °C, with warmer regions having higher Topteco values than colder regions. In tropical forests in particular, Topteco is close to growing-season air temperature and is projected to fall below it under all scenarios of future climate, suggesting a limited safe operating space for these ecosystems under future warming.
| Original language | English |
|---|---|
| Pages (from-to) | 772-779 |
| Number of pages | 8 |
| Journal | Nature Ecology and Evolution |
| Volume | 3 |
| Issue number | 5 |
| DOIs | |
| State | Published - May 1 2019 |
Funding
This study was supported by the Strategic Priority Research Program (A) of the Chinese Academy of Sciences (Grant No. XDA20050101), the National Natural Science Foundation of China (41530528) and the National Key R&D Program of China (2017YFA0604702). This work used eddy covariance data acquired by the FLUXNET community and in particular by the following networks: AmeriFlux (US Department of Energy, Biological and Environmental Research, Terrestrial Carbon Program (DE-FG02-04ER63917 and DE-FG02-04ER63911)), AfriFlux, AsiaFlux, CarboAfrica, CarboEuropeIP, CarboItaly, CarboMont, ChinaFlux, Fluxnet-Canada (supported by CFCAS, NSERC, BIOCAP, Environment Canada and NRCan), GreenGrass, KoFlux, LBA, NECC, OzFlux, TCOS-Siberia and USCCC. We acknowledge the financial support to the eddy covariance data harmonization provided by CarboEuropeIP, FAO-GTOS-CO, iLEAPS, Max Planck Institute for Biogeochemistry, National Science Foundation, University of Tuscia, Université Laval and Environment Canada, and the US Department of Energy and the database development and technical support from Berkeley Water Center, Lawrence Berkeley National Laboratory, Microsoft Research eScience, Oak Ridge National Laboratory, University of California-Berkeley and University of Virginia. P.C., J.P. and I.A.J. would like to acknowledge the financial support from the European Research Council Synergy Grant No. ERC-SyG-2013-610028 IMBALANCE-P. P.C. was also supported by the French Agence Nationale de la Recherche Convergence Lab Changement climatique et usage des terres (CLAND). I.A.J. acknowledges the Methusalem funding of the Flemish Community through the Research Council of the University of Antwerp. T.F.K. was supported by the NASA Terrestrial Ecology Program IDS Award NNH17AE86I. J.M. and X.S. are supported by the Terrestrial Ecosystem Science Scientific Focus Area project funded through the Terrestrial Ecosystem Science Program in the Climate and Environmental Sciences Division of the Biological and Environmental Research Program in the US Department of Energy Office of Science. Oak Ridge National Laboratory is supported by the Office of Science of the US Department of Energy under Contract No. DE-AC05-00OR22725. M.C. was supported by a grant overseen by the French National Research Agency (ANR) as part of the Investissements d’Avenir program (ANR-11-LABX-0002-01, Lab of Excellence ARBRE).