Oceans Absorb Record Heat in 2025, Ninth Straight Year

The world's oceans absorbed a record amount of heat in 2025, marking the ninth consecutive year of new highs and underscoring the accelerating pace of global warming, according to an international study published this week in Advances in Atmospheric Sciences.

The analysis, led by researchers from the Institute of Atmospheric Physics at the Chinese Academy of Sciences and involving more than 50 scientists from 31 institutions, found that the upper 2,000 meters of the ocean gained 23 zettajoules of heat energy compared to 2024. This increase, equivalent to about 200 times humanity's global electricity consumption in 2023, reflects the ocean's role in storing over 90 percent of the excess heat trapped by greenhouse gas emissions. Data came from multiple sources, including the U.S. National Oceanic and Atmospheric Administration's National Centers for Environmental Information, the European Union's Copernicus Marine Service, and the Chinese Academy of Sciences.

Global sea surface temperatures in 2025 averaged about 0.5 degrees Celsius (0.9 degrees Fahrenheit) above the 1981-2010 baseline, ranking as the third warmest on record since measurements began in the late 19th century. This...