A new study revealed that the world's oceans absorbed a record 23 zettajoules of heat in 2025, marking the eighth consecutive year of increasing ocean heat absorption. The research, published in the journal Advances in Atmospheric Science on Friday, was conducted by a team of over 50 scientists from the United States, Europe, and China.

The amount of heat absorbed in 2025 significantly surpassed the 16 zettajoules absorbed in 2024, according to the study. To put the scale into perspective, a zettajoule is one sextillion joules, or 23 followed by 21 zeros. John Abraham, a professor of thermal science at the University of St. Thomas, was one of the researchers involved in the study.

Researchers have been tracking ocean heat absorption since 2018, consistently finding increases year after year. These measurements, which began in the 1960s, indicate a concerning trend of escalating heat accumulation within the world's oceans. The study highlights the crucial role oceans play in mitigating climate change by absorbing a significant portion of the Earth's excess heat. However, this absorption comes at a cost, leading to rising sea temperatures, altered marine ecosystems, and contributing to more extreme weather events.