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 over 50 scientists from the United States, Europe, and China, who analyzed data on ocean heat content since 2018. Their findings showed a consistent upward trend, with 2025 setting a new high since modern measurements began in the 1960s. A joule, a standard unit of energy, is equivalent to the energy needed to power a small lightbulb for one second or slightly heat a gram of water. A zettajoule is one sextillion joules, meaning the 23 zettajoules absorbed in 2025 is an enormous amount of energy.

The increasing ocean heat absorption has profound implications for the global climate system. Oceans act as a major heat sink, absorbing over 90% of the excess heat trapped by greenhouse gases. 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 disrupt marine ecosystems, impacting fisheries and coastal communities.

Scientists use sophisticated climate models and data analysis techniques, including artificial intelligence (AI), to understand and predict these changes. AI algorithms can process vast amounts of ocean temperature data, identify patterns, and project future trends with increasing accuracy. These models are crucial for informing policy decisions and developing strategies to mitigate the impacts of climate change.

The continued warming of the oceans underscores the urgency of reducing greenhouse gas emissions. International efforts to limit global warming, such as the Paris Agreement, aim to curb emissions and prevent further increases in ocean heat absorption. The researchers involved in the study plan to continue monitoring ocean heat content and refining their models to provide more precise projections of future climate scenarios.