Abstract
Carbon emissions from groundwater depletion (GWD) can be involved in the global carbon cycle; however, it is poorly understood that how much contribution they have. We here generate two maps on global GWD using measurements from >171,000 monitoring wells and on global groundwater bicarbonate (HCO₃⁻) concentrations using the meta data from 28,902 measurements. We then evaluate the global GWD-induced carbon emissions and show that 1) the total emissions from GWD can be a type of significant source (52 ± 18 MMT CO₂ yr⁻¹) within the global carbon cycle, which have exceeded the net emissions of grasslands (~35 MMT CO₂ yr⁻¹), one of the world’s main carbon sources; 2) the total GWD is approximately 550 ± 73 km³/year in recent 20 years, which is generally consistent with previous studies; 3) China (6.7 ± 1.6 MMT CO₂ yr⁻¹), Brazil (6.6 ± 2.5MMT CO₂ yr⁻¹), and India (5.8 ± 1.5 MMT CO₂ yr⁻¹) are the top three contributors of GWD-induced carbon emissions.
Acknowledgements
We thank the Global Gravity-based Groundwater Product (G3P) project—funded by the EU Horizon 2020 program—for providing the comprehensive global groundwater storage dataset that underpinned this study. We are grateful to the International Groundwater Resources Assessment Centre (IGRAC) for critical hydrogeological datasets and technical insights, and to the China Geological Environment Monitoring Institute of the China Geological Survey (CGS), United States Geological Survey (USGS), Indian Water Resources Information System (IWRIS) The Geological Survey of Denmark and Greenland (GEUS)for regional groundwater monitoring data and expertise, which enhanced the spatial representativeness of our analysis. We are also grateful for Global Environmental Monitoring System (GEMS) for expanding the groundwater quality monitoring data.
Funding
The research is supported by the National Key R&D Program of China (Grant No. 2023YFC3705904 and 2020YFC1807900), National Natural Science Foundation of China (Grant No. 52079088), and the CAS Interdisciplinary Innovation Team (Grant No. JCTD-2019-04).
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Sun, T., He, L., Zhang, F. et al. Groundwater depletion contributes to an increase in global carbon emissions. Nat Commun (2026). https://doi.org/10.1038/s41467-026-73521-2
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DOI: https://doi.org/10.1038/s41467-026-73521-2
