2025年，全球海洋吸收了有记录以来最多的热量，这是自2018年以来连续第八年刷新纪录。研究显示，2025年海洋额外吸收了23泽焦耳的热量，高于2024年的16泽焦耳，创下自20世纪60年代现代观测开始以来的最高值。23泽焦耳等于2.3×10^22焦耳，能量规模相当于在海洋中引爆约12枚广岛原子弹，或将20亿个奥林匹克标准游泳池中的水煮沸。

海洋是地球最大的热汇，吸收了超过90%的多余热量。尽管2025年的海表温度略低于2024年，但这并不意味着整体变冷，因为大量热量被输送至深海。厄尔尼诺和拉尼娜等气候现象会改变热量在海洋中的分布，解释了2024年至2025年间海洋热含量的大幅跃升。仅依赖海表温度会低估气候变化的真实规模。

该研究整合了数学模型与多源观测数据，包括自20世纪60年代开始的深海测量，以及21世纪初部署的3500多个Argo浮标网络。结果表明，深海热量积累是评估全球变暖最稳定的指标。科学家指出，海洋在过去约100年中积累的热量，即使今天停止使用化石燃料，也需要数百年才能重新分布和消散，其长期影响不可逆转。

In 2025, the world’s oceans absorbed more heat than in any previous year on record, marking the eighth consecutive year of new highs since 2018. The study found that oceans absorbed an additional 23 zettajoules of heat in 2025, up from 16 zettajoules in 2024, the highest value since modern measurements began in the 1960s. Twenty-three zettajoules equals 2.3×10^22 joules, an energy amount comparable to detonating about 12 Hiroshima atomic bombs in the ocean, or boiling 2 billion Olympic swimming pools.

The oceans are Earth’s largest heat sink, absorbing more than 90 percent of excess heat. Although sea surface temperatures in 2025 were slightly lower than in 2024, this does not indicate overall cooling, because much of the heat is transported into the deep ocean. Climate patterns such as El Niño and La Niña alter heat distribution, explaining the sharp increase in ocean heat content between 2024 and 2025. Relying only on surface temperatures underestimates the true scale of climate change.

The study combines models with diverse observations, including deep-ocean measurements dating back to the 1960s and data from more than 3,500 Argo floats deployed since the early 2000s. The findings show that deep-ocean heat content is the most stable indicator of global warming. Scientists note that the heat accumulated over roughly the past 100 years will take hundreds of years to circulate and dissipate, even if fossil fuel use stopped today, making the long-term impact unavoidable.