As of 2025, the global full-depth ocean heat content (OHC) has risen by 481 ± 48 ZJ since 1960, with a pronounced increase of 24 ± 6 ZJ from 2024 to 2025. The highest elevations in OHC were measured in the Southern and Pacific Oceans.
Key points
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The 0–300 m, 300–700 m, 700–2,000 m, and below-2,000 m layers have accounted for approximately 40%, 22%, 29%, and 9% of total OHC increase, respectively, since 1960.
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The Pacific Ocean, Southern Ocean, abyssal oceans below 2,000 m, Indian Ocean, and Atlantic Ocean contributed 14.2, 10.0, 0.8, –0.8 and –0.6 ZJ, respectively, to the global OHC change between the years 2024 and 2025.
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The most vigorous ocean warming from 2024 to 2025 occurred in the tropical Western Pacific, Southeast Indian Oceans, and the Indian sector of the Southern Ocean.
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Data availability
Argo data were collected and made freely available by the International Argo Program and the national programmes contributing to it (https://argo.ucsd.edu, https://www.ocean-ops.org). The IAP/CAS (Institute of Atmospheric Physics, Chinese Academy of Sciences) observation and model data are available at http://www.ocean.iap.ac.cn/.
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Acknowledgements
L.C. acknowledges financial support from the National Key R&D Program of China (Grant No. 2023YFF0806500), the National Natural Science Foundation of China (Grant No. 42406195, 42276205), the International Partnership Program of the Chinese Academy of Sciences (Grant No. 060GJHZ2024064MI), and the National Key Scientific and Technological Infrastructure project “Earth System Science Numerical Simulator Facility” (EarthLab). We acknowledge the World Climate Research Programme’s Working Group on Coupled Modelling, which is responsible for CMIP, and we thank the climate modelling groups for producing and making available their model output. We thank the Oceanographic Data Center of the Institute of Oceanology, Chinese Academy of Sciences for data storage support. The Argo Program is part of the Global Ocean Observing System.
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Bao, S., Pan, Y., Li, Y. et al. Ocean heat content in 2025. Nat Rev Earth Environ (2026). https://doi.org/10.1038/s43017-026-00775-1
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DOI: https://doi.org/10.1038/s43017-026-00775-1
