Abstract
Unraveling drivers of the interannual variability of tropical land carbon cycle is critical for understanding land carbon-climate feedbacks. Here we utilize two generations of factorial model experiments to show that interannual variability of tropical land carbon uptake under both present and future climate is consistently dominated by terrestrial water availability variations in Earth system models. The magnitude of this interannual sensitivity of tropical land carbon uptake to water availability variations under future climate shows a large spread across the latest 16 models (2.3 ± 1.5 PgC/yr/Tt H2O), which is constrained to 1.3 ± 0.8 PgC/yr/Tt H2O using observations and the emergent constraint methodology. However, the long-term tropical land carbon-climate feedback uncertainties in the latest models can no longer be directly constrained by interannual variability compared with previous models, given that additional important processes are not well reflected in interannual variability but could determine long-term land carbon storage. Our results highlight the limited implication of interannual variability for long-term tropical land carbon-climate feedbacks and help isolate remaining uncertainties with respect to water limitations on tropical land carbon sink in Earth system models.
| Original language | English |
|---|---|
| Article number | 348 |
| Journal | Communications Earth and Environment |
| Volume | 5 |
| Issue number | 1 |
| DOIs | |
| State | Published - Dec 2024 |
Funding
We acknowledge the World Climate Research Programme, which, through its Working Group on Coupled Modelling, coordinated and promoted CMIP6. We thank the climate modeling groups for producing and making available their model output, the Earth System Grid Federation (ESGF) for archiving the data and providing access, and the multiple funding agencies who support CMIP6 and ESGF. We thank all contributors to the CMIP6 experiments. L.L. and S.I.S. acknowledge support from HORIZON.2.5 under grant agreement 101056939 (RESCUE). L.L., R.P., R.F., and S.I.S. also acknowledge support from the EU Horizon 2020 Research and Innovation Program under grant agreement 821003 (4C). R.F. also acknowledge support EU Horizon2020 under grant agreement 101003536 (ESM 2025). A.A. also acknowledges support from the European Union\u2019s Horizon Europe research and innovation program under grant agreement 101081193 (OptimESM project)\u00A0and\u00A0from ICSC \u2013 Centro Nazionale di Ricerca in High Performance Computing, Big Data and Quantum Computing, funded by European Union \u2013 NextGenerationEU (Concession Decree N. 1031 of 17/06/2022 adopted by the Italian Ministry of University and Research). J.M. was supported by the Reducing Uncertainties in Biogeochemical Interactions through Synthesis and Computation Science Focus Area (RUBISCO SFA) project in the Earth and Environmental Systems Sciences Division (EESSD) of the Biological and Environmental Research (BER) office in the US Department of Energy (DOE) Office of Science. Oak Ridge National Laboratory is managed by UT-BATTELLE, LLC, for the DOE under contract no. DE-AC05-00OR22725.\u00A0H.K. was\u00A0supported by the National Research Foundation of Korea (NRF) grant funded by Korea Government (MSIT) (2021H1D3A2A03097768). We acknowledge the World Climate Research Programme, which, through its Working Group on Coupled Modelling, coordinated and promoted CMIP6. We thank the climate modeling groups for producing and making available their model output, the Earth System Grid Federation (ESGF) for archiving the data and providing access, and the multiple funding agencies who support CMIP6 and ESGF. We thank all contributors to the CMIP6 experiments. L.L. and S.I.S. acknowledge support from HORIZON.2.5 under grant agreement 101056939 (RESCUE). L.L., R.P., R.F., and S.I.S. also acknowledge support from the EU Horizon 2020 Research and Innovation Program under grant agreement 821003 (4C). R.F. also acknowledge support EU Horizon2020 under grant agreement 101003536 (ESM 2025). A.A. also acknowledges support from the European Union\u2019s Horizon Europe research and innovation program under grant agreement 101081193 (OptimESM project) and from ICSC \u2013 Centro Nazionale di Ricerca in High Performance Computing, Big Data and Quantum Computing, funded by European Union \u2013 NextGenerationEU (Concession Decree N. 1031 of 17/06/2022 adopted by the Italian Ministry of University and Research). J.M. was supported by the Reducing Uncertainties in Biogeochemical Interactions through Synthesis and Computation Science Focus Area (RUBISCO SFA) project in the Earth and Environmental Systems Sciences Division (EESSD) of the Biological and Environmental Research (BER) office in the US Department of Energy (DOE) Office of Science. Oak Ridge National Laboratory is managed by UT-BATTELLE, LLC, for the DOE under contract no. DE-AC05-00OR22725. H.K. was supported by the National Research Foundation of Korea (NRF) grant funded by Korea Government (MSIT) (2021H1D3A2A03097768).