Ocean heat sets a new record and is intensifying climate impacts

Scientists report 2025 set a new record for global ocean heat, and the oceans absorbed more than 90% of the heat trapped by human-caused emissions.

New analysis finds the world's oceans stored a record amount of heat in 2025. More than 90% of the heat trapped by human-caused emissions is taken up by the oceans, so ocean heat is a leading indicator of global warming. The study combined temperature data from instruments and three independent teams to estimate heat content in the top 2,000 metres of the ocean. Scientists link higher ocean heat to stronger storms, heavier rainfall, longer marine heatwaves and thermal expansion that raises sea levels. Key findings: - 2025 set a new global ocean heat record based on measurements through the top 2,000 metres. - Oceans absorb more than 90% of the excess heat from human-caused emissions. - Higher ocean heat is associated with stronger tropical storms, heavier rainfall, longer marine heatwaves and thermal expansion that contributes to sea level rise. - Warming was uneven in 2025, with notable hotspots in the tropical and South Atlantic, the North Pacific and the Southern Ocean; the North Atlantic and Mediterranean also showed warming, increased salinity, higher acidity and lower oxygen levels. Summary: Rising ocean heat is linked to changes in weather patterns, marine conditions and ongoing sea level rise. The analysis indicates ocean heat records are likely to continue while global heat increases. Undetermined at this time.