Ocean Heat Content Sets Another Record in 2025

Abstract Global ocean warming continued unabated in 2025 in response to increased greenhouse gas concentrations and recent reductions in sulfate aerosols, reflecting the long-term accumulation of heat within the climate system, with conditions evolving toward La Niña during the year. In 2025, global upper 2000 m ocean heat content (OHC) increased by ∼23 ± 8 ZJ relative to 2024 according to IAP/CAS estimates. CIGAR-RT, and Copernicus Marine data confirm the continued ocean heat gain. Regionally, about 33% of the global ocean area ranked among its historical (1958–2025) top three warmest conditions, while about 57% fell within the top five, including the tropical and South Atlantic Ocean, Mediterranean Sea, North Indian Ocean, and Southern Oceans, underscoring the broad ocean warming across basins. Multiple datasets consistently indicate ocean warming, as measured by 0–2000 m OHC, increased from 0.14 ± 0.03 W m −2 (10 yr) −1 during 1960–2025 to 0.32 ± 0.14 W m −2 (10 yr) −1 during 2005–2025 (IAP/CAS), the latter being consistent with EEI (Earth’s Energy Imbalance) estimates within uncertainties. In contrast, the global annual mean sea surface temperature (SST) in 2025 was 0.49°C above the 1981–2010 baseline and 0.12 ± 0.03°C lower than in 2024 (IAP/CAS; similar in CMA-SST, FY3 MWRI SST, ERSSTv5 and Copernicus Marine data), consistent with the development of La Niña conditions, but still ranking as the third-warmest year on record.

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Publication Details

Journal
Advances in Atmospheric Sciences
Published
2026-01-09
DOI
https://doi.org/10.1007/s00376-026-5876-0
Citations
1
Primary Topic
Oceanographic and Atmospheric Processes
Type
article
Field-Weighted Citation Impact
28.32

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Ocean Heat Content Sets Another Record in 2025

L. Cheng, John Abraham, Licheng Feng, Viktor Gouretski et al.
1 citations
Advances in Atmospheric Sciences
Oceanographic and Atmospheric Processes
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article

Ocean Heat Content Sets Another Record in 2025

L. Cheng, John Abraham, Licheng Feng, Viktor Gouretski, Wangxu Wei, DaKui Wang, Zhetao Tan, Huizan Wang, Xingrong Chen, Guancheng Li, F T WANG, Z. Wang, Gengxin Chen, Jifu Du, Franco Reseghetti, Senliang Bao, James Reagan, Zenghong Liu, Alexey Mishonov, John Fasullo, Albertus Sulaiman, Zeke Hausfather, Yuying Pan, Hengqian Yan, Lifan Chen, Rongwang ZHANG, Yujing Zhu, Xu Liu, Lei Chen, Y. Liu, Jiang Zhu, Zhanhong Ma, Huifeng Yuan, Yuanlong Li, Lijuan Cao, Fujiang Yu, Kewei Lyu, Flora Gues, Andrea Storto, Miao Zhang, Garrett Graham, Michael Mayer, Xungang Yin, Ricardo Locarnini, Fei Zheng, Xinyi Song, Xiangzhou Song, Liying Wan, Chunxue Yang, Karina Von Schuckmann, Michael E. Mann
article en
1 citations

Abstract

Abstract Global ocean warming continued unabated in 2025 in response to increased greenhouse gas concentrations and recent reductions in sulfate aerosols, reflecting the long-term accumulation of heat within the climate system, with conditions evolving toward La Niña during the year. In 2025, global upper 2000 m ocean heat content (OHC) increased by ∼23 ± 8 ZJ relative to 2024 according to IAP/CAS estimates. CIGAR-RT, and Copernicus Marine data confirm the continued ocean heat gain. Regionally, about 33% of the global ocean area ranked among its historical (1958–2025) top three warmest conditions, while about 57% fell within the top five, including the tropical and South Atlantic Ocean, Mediterranean Sea, North Indian Ocean, and Southern Oceans, underscoring the broad ocean warming across basins. Multiple datasets consistently indicate ocean warming, as measured by 0–2000 m OHC, increased from 0.14 ± 0.03 W m −2 (10 yr) −1 during 1960–2025 to 0.32 ± 0.14 W m −2 (10 yr) −1 during 2005–2025 (IAP/CAS), the latter being consistent with EEI (Earth’s Energy Imbalance) estimates within uncertainties. In contrast, the global annual mean sea surface temperature (SST) in 2025 was 0.49°C above the 1981–2010 baseline and 0.12 ± 0.03°C lower than in 2024 (IAP/CAS; similar in CMA-SST, FY3 MWRI SST, ERSSTv5 and Copernicus Marine data), consistent with the development of La Niña conditions, but still ranking as the third-warmest year on record.

Advances in Atmospheric Sciences
NSF National Center for Atmospheric Research (US), University of Vienna (AT), China Meteorological Administration (CN), University of Auckland (NZ), European Centre for Medium-Range Weather Forecasts (GB), University of St. Thomas - Minnesota (US), Hohai University (CN), National University of Defense Technology (CN), Xiamen University (CN), Chinese Academy of Sciences (CN), Ministry of Ecology and Environment (CN), Ministry of Natural Resources (CN), NOAA Oceanic and Atmospheric Research (US), Istituto Nazionale di Geofisica e Vulcanologia (IT), École Normale Supérieure - PSL (FR), Laboratoire de Météorologie Dynamique (FR), Institute of Oceanology (CN), South China Sea Institute Of Oceanology (CN), Computer Network Information Center (CN), Second Institute of Oceanography (CN), Institut Pierre-Simon Laplace (FR), Mercator Ocean (France) (FR), Shandong Marine Resource and Environment Research Institute (CN), Beijing Meteorological Bureau (CN), National Marine Environmental Forecasting Center (CN), Institute of Atmospheric Physics (CN), National Research Council (IT), NOAA National Centers for Coastal Ocean Science (US), Profusa (United States) (US), Cooperative Institute for Climate and Satellites (US), National Research and Innovation Agency (ID), National Marine Data and Information Service, Bristol-Myers Squibb (Switzerland) (CH), University of Maryland, College Park (US), University of Pennsylvania (US), University of North Carolina at Asheville (US)
National Science Foundation, U.S. Department of Energy, National Aeronautics and Space Administration, European Space Agency, National Natural Science Foundation of China, Chinese Academy of Sciences, Nuclear Safety and Security Commission, Centro Nacional de Investigaciones Cardiovasculares, Istituto Nazionale di Geofisica e Vulcanologia, National Oceanic and Atmospheric Administration, Oak Ridge Institute for Science and Education, Nutrition Obesity Research Center, University of North Carolina, EarthLab, University of Washington, Lawrence Livermore National Laboratory, Lawrence Berkeley National Laboratory, Pacific Northwest National Laboratory
Life below water
Openalex Percentile: Top 2%
Oceanographic and Atmospheric Processes
28.32
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