Abstract
2024 is the hottest year on record, accompanied by extreme precipitation, droughts and fires. The global atmospheric CO2 growth rate in 2024 reached a historic high of 3.73 ppm yr-1, significantly surpassing the previous record set during the 2015/16 El Niño event. Here, we investigate the causes and underlying mechanisms of this record-high growth rate by combining satellite-based atmospheric inversions and estimates of gross primary production and fire emissions. We find that the record-high CO2 growth rate is due to large reductions in the land CO2 sink. This is dominated by a dramatic increase in total ecosystem respiration, which occurred primarily in grass and shrub lands, owing to compound hot-wet climatic conditions in 2024. Given the projected increase in the frequency and intensity of compound pluvial-hot extremes under warming, changes in ecosystem respiration will become more drastic and cause positive feedback to climate warming.
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Data availability
All data used in this study are publicly available. The inversions of GCASv2 are available at https://github.com/Guanyu-nju/Global_2024sink.git. The GOSIF GPP is available at https://globalecology.unh.edu/data/GOSIF-GPP.html. The FluxSat v2.2 GPP is available at https://daac.ornl.gov/VEGETATION/guides/FluxSat_GPP_FPAR.html. The GFED 4.1 s fire emissions are available at https://www.geo.vu.nl/~gwerf/GFED/GFED4/. The CAMS GFAS fire emissions are available at https://www.ecmwf.int/en/forecasts/dataset/global-fire-assimilation-system. The TROPOMI SIF data are available at https://radiantearth.github.io/stac-browser/#/external/data-portal.s5p-pal.com/api/s5p l2/collections/L2__SIF___. The GRACE/FO TWS data are available at https://www2.csr.utexas.edu/grace/RL06_mascons.html. The EC data collected from ICOS, AmeriFlux, and OzFlux networks are available at https://www.icos-cp.eu/, https://ameriflux.lbl.gov/, and https://www.ozflux.org.au/, respectively. The MODIS NDVI and land cover map, the GLDAS TWS, and the air temperature, vapor pressure deficit, and solar radiation from ERA5-Land are available from the Google Earth Engine (GEE) platform at https://developers.google.com/earth-engine/datasets/.
Code availability
The MATLAB codes used in this study are available via GitHub at https://github.com/Guanyu-nju/Global_2024sink.git.
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Acknowledgements
This work is supported by the National Key R&D Program of China (grant no. 2023YFB3907404 to F.J.), the National Natural Science Foundation of China (grant no. 42377102 to F.J.), and the Jiangsu Provincial Science Fund for Distinguished Young Scholars (grant no. BK20231530 to F.J.). J.X. is supported by the University of New Hampshire via the Iola Hubbard Climate Change Endowment. The OCO-2 data are produced by the OCO project at the Jet Propulsion Laboratory, California Institute of Technology, and obtained from the data archive at the NASA Goddard Earth Science Data and Information Services Center. We acknowledge all atmospheric data providers to obspack_co2_1_GLOBALVIEWplus_v10.1_2024-11-13 and obspack_co2_1_NRT_v10.1_2025-02-07. We are also grateful to the High-Performance Computing Center (HPCC) of Nanjing University for doing the numerical calculations in this paper on its blade cluster system.
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F.J. and G.D. conceptualized and designed the study. F.J. and G.D. performed the analyses and wrote the paper. F.J. provided the atmospheric inversion estimates. W.J. and Yongguang Zhang provided the prior biosphere flux used in the atmospheric inversion. J.X. and X.L. provided the GOSIF GPP data, and G.R.W. provided the GFEDv4.1s fire emission data. F.J., G.D., L.Z., G.L. and Yuanyuan Zhang prepared the figures. J.P., P.C., Yongguang Zhang, J.X., X.W., W.Y., Y.H., C.Y., L.L., L.F., M.W., J.W., Y.Z., J.T., W.H., H.W. and J.M.C offered thoughts on the data analysis and the writing of the manuscript. All authors contributed during the writing of the paper.
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Dong, G., Jiang, F., Ju, W. et al. Dramatic increase in ecosystem respiration causes record-breaking atmospheric CO2 growth rate in 2024. Nat Commun (2026). https://doi.org/10.1038/s41467-026-72189-y
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DOI: https://doi.org/10.1038/s41467-026-72189-y
