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Another Record: Ocean Warming Continues through 2021 despite La Niña Conditions


The increased concentration of greenhouse gases in the atmosphere from human activities traps heat within the climate system and increases ocean heat content (OHC). Here, we provide the first analysis of recent OHC changes through 2021 from two international groups. The world ocean, in 2021, was the hottest ever recorded by humans, and the 2021 annual OHC value is even higher than last year’s record value by 14 ± 11 ZJ (1 zetta J = 1021 J) using the IAP/CAS dataset and by 16 ± 10 ZJ using NCEI/NOAA dataset. The long-term ocean warming is larger in the Atlantic and Southern Oceans than in other regions and is mainly attributed, via climate model simulations, to an increase in anthropogenic greenhouse gas concentrations. The year-to-year variation of OHC is primarily tied to the El Niño-Southern Oscillation (ENSO). In the seven maritime domains of the Indian, Tropical Atlantic, North Atlantic, Northwest Pacific, North Pacific, Southern oceans, and the Mediterranean Sea, robust warming is observed but with distinct inter-annual to decadal variability. Four out of seven domains showed record-high heat content in 2021. The anomalous global and regional ocean warming established in this study should be incorporated into climate risk assessments, adaptation, and mitigation.


人类活动导致大气中温室气体的浓度上升,造成了地球系统的净热量吸收和海洋热含量增加。本文发布了两个国际机构的2021年海洋热含量数据,数据表明:2021年海洋升温持续——成为有现代海洋观测记录以来海洋最暖的一年。相对于2020年,2021年全球海洋上层2000米热含量上升了14 ± 11 ZJ (1 zetta J = 1021 J)(IAP/CAS数据)、以及16 ± 10 ZJ(NOAA/NCEI数据)。海洋长期变暖趋势在南大洋、中低纬度大西洋区域更强,地球系统模式的单个因子强迫实验证明,温室气体增加是主要的驱动因子;而年际尺度的海洋热含量变化主要受到厄尔尼诺-南方涛动模态调控。此外,本文给出了全球7个主要海域的海洋变暖测算,发现地中海、北大西洋、南大洋、北太平洋海区温度均创历史新高。最后,本文提出需要充分将全球和区域海洋变暖的影响纳入气候风险评估、气候变化影响和应对当中。


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The IAP/CAS analysis is supported by the National Natural Science Foundation of China (Grant No. 42122046, 42076202), Strategic Priority Research Program of the Chinese Academy of Sciences (Grant No. XDB42040402), National Natural Science Foundation of China (Grant No. 42076202), National Key R&D Program of China (Grant No. 2017YFA0603202), and Key Deployment Project of Centre for Ocean Mega-Research of Science, CAS (Grant Nos. COMS2019Q01 and COMS2019Q07). NCAR is sponsored by the US National Science Foundation. The efforts of Dr. Fasullo in this work were supported by NASA Award 80NSSC17K0565, and by the Regional and Global Model Analysis (RGMA) component of the Earth and Environmental System Modeling Program of the U.S. Department of Energy’s Office of Biological & Environmental Research (BER) via National Science Foundation IA 1844590. The efforts of Dr. Mishonov and Mr. Reagan were partially supported by NOAA (Grant NA14NES4320003 to CISESSMD at the University of Maryland). The IAP/CAS data are available at and The NCEI/NOAA data are available at The historical XBT data along the MX04 line (Genova-Palermo) are available through SeaDataNet - Pan-European infrastructure ( for ocean and marine data management. Since 2021, XBT data have been collected in the framework of the MACMAP project funded by the Istituto Nazionale di Geofisica e Vulcanologia in agreement between INGV, ENEA, and GNV SpA shipping company that provides hospitality on their commercial vessels.

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Correspondence to Lijing Cheng.

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Article Highlights

• The world ocean, in 2021, was the hottest ever recorded by humans.

• The warming pattern is mainly attributed to increased anthropogenic greenhouse gas concentrations, offset by the impact of aerosols.

• Ocean warming has far-reaching consequences and should be incorporated into climate risk assessments, adaptation, and mitigation.

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Cheng, L., Abraham, J., Trenberth, K.E. et al. Another Record: Ocean Warming Continues through 2021 despite La Niña Conditions. Adv. Atmos. Sci. 39, 373–385 (2022).

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Key words

  • La Niña
  • ocean heat
  • ocean warming
  • attribution
  • observation


  • 拉尼娜
  • 海洋热含量
  • 海洋变暖
  • 归因
  • 观测