A new study revealed that the world's oceans absorbed a record-breaking 23 zettajoules of heat in 2025, marking the eighth consecutive year of increasing ocean heat absorption. The research, published Friday in the journal Advances in Atmospheric Science, indicated a significant increase from the 16 zettajoules absorbed in 2024.

The study was conducted by a team of more than 50 scientists from the United States, Europe, and China, who analyzed data on ocean heat content dating back to the 1960s. Their findings showed that 2025 was the year with the highest recorded ocean heat absorption since modern measurements began.

A joule is a standard unit of energy, with a zettajoule representing one sextillion joules. To put it in perspective, the 23 zettajoules absorbed by the oceans in 2025 can be written as 23,000,000,000,000,000,000,000 joules.

The continuous increase in ocean heat absorption has significant implications for the global climate system. Oceans act as a major heat sink, absorbing over 90% of the excess heat trapped by greenhouse gas emissions. This absorption helps to regulate global temperatures, but it also leads to rising sea levels, altered ocean currents, and more frequent and intense marine heatwaves. These changes can have devastating effects on marine ecosystems, including coral reefs, fisheries, and coastal communities.

Scientists use sophisticated climate models, often powered by artificial intelligence, to analyze ocean heat data and project future trends. These models incorporate vast amounts of data on ocean temperature, salinity, and circulation patterns to simulate the complex interactions within the climate system. AI algorithms can identify patterns and relationships in the data that would be difficult or impossible for humans to detect, improving the accuracy of climate projections.

The researchers involved in the study emphasized the urgent need to reduce greenhouse gas emissions to mitigate the impacts of climate change on the oceans. Further research will focus on understanding the regional variations in ocean heat absorption and the specific mechanisms driving these changes. The ongoing monitoring of ocean heat content is crucial for tracking the progress of climate mitigation efforts and for informing adaptation strategies to protect vulnerable marine ecosystems and coastal communities.