The study, involving more than 50 scientists from 31 research institutions worldwide, indicates that the increase in ocean heat last year was 23 zettajoules (a zettajoule is a joule, the standard unit of heat energy, followed by 21 zeros).

This “is equivalent to about 37 years of global primary energy consumption [that which is available in nature]”, using 2023 energy consumption as a reference, according to a statement released by the Institute of Atmospheric Physics of the Chinese Academy of Sciences, to which the corresponding author of the study, Lijing Cheng, is affiliated.

Covering approximately 71% of the planet’s surface, the ocean absorbs 30% of all carbon dioxide emissions (CO2, the most important greenhouse gas). It captures 90% of the heat generated by these excess emissions, making it the primary heat reservoir of the climate system.

According to the statement, by reflecting the accumulation of heat stored in the ocean, ocean heat content (OHC) “provides one of the best indicators of long-term climate change.”

The rise in ocean temperature “drives sea level rise, (…) strengthens and prolongs heat waves and intensifies extreme weather events, increasing heat and humidity in the atmosphere,” which causes the continued increase in ocean heat and makes record highs more likely.

Scientists have found that OHC reached its highest level on record in 2025, confirming the continued increase in ocean heat content.

The research also showed that ocean warming is not uniform, with some areas warming faster than others.

By 2025, approximately 16% of the global ocean area will have reached a record OCC (Ocean Climate Change), and around 33% will be among the three highest values ​​ever recorded, with the areas experiencing the most warming including the tropical zones of the South Atlantic and North Pacific and the Antarctic Ocean.

Overall, the trend of ocean warming has been stronger since the 1990s, with successive records broken over the past nine years.