Earth's oceans have stored an unprecedented amount of heat since the beginning of modern records. This accumulated energy, though invisible, will manifest through even more intense weather events.
Acting as the planet's true thermal reservoir, the oceans capture over 90% of the excess energy produced by greenhouse gases. This capture has now reached unprecedented levels, disrupting balances and directly altering weather conditions on a global scale.
Illustration image Pixabay
To quantify this heat, scientists cross-referenced information from several international agencies. Data from the Institute of Atmospheric Physics in China, Copernicus Marine in Europe, and NOAA in the United States converge on the same finding. Together, they indicate that the ocean heat content reached a record high in 2025, with an accumulation of approximately 23 zettajoules. This value is equivalent to 37 years of global energy consumption.
This progression does not affect all seas uniformly. In 2025, about 16% of the ocean surface experienced its highest temperatures, particularly in tropical zones, the South Atlantic, and the North Pacific. Such regional heterogeneity suggests more pronounced effects on certain marine ecosystems.
Furthermore, surface temperatures, although slightly lower than in 2024, remain abnormally high. They still exceed the average of previous decades by almost 0.5°C (~0.9°F). These warmer waters fuel increased evaporation, which strengthens intense weather episodes, such as the floods observed in Southeast Asia or the drought periods in the Middle East during 2025.
The continued increase in ocean heat has direct repercussions on our environment. It contributes to sea-level rise and increases the potential power of tropical cyclones. These transformations influence not only coastal areas but also communities and economic activities dependent on marine resources.
Research on this topic continues. Various studies are examining regional disparities, for example off the coast of China or in the Indian Ocean.