Global sea surface temperature breaks 2024 record

The sea surface temperature averaged across the extra-polar global ocean, between 60°S and 60°N, reached 21.1°C on Aug. 22, surpassing the previous record of 21.09°C. The C3S ERA5 dataset used for the record extends back to 1979, the period for which satellite observations make the data more reliable.

The timing of the new record is notable because global ocean temperatures are normally at their highest in March and April, following the Southern Hemisphere summer. The Aug. 22 reading also exceeded the previous highest August temperature of 20.98°C, recorded in 2023.

C3S said the record comes after a series of monthly records and near-record temperatures across the extra-polar ocean throughout 2026. A strong El Niño event is now developing in the tropical Pacific, adding further heat to an ocean that has already warmed over decades because of human-driven climate change.

The World Meteorological Organization expects El Niño to strengthen in the coming months, while C3S seasonal forecasts suggest the event could reach levels not seen for several decades.

“This record is another clear signal of an ocean under growing stress. El Niño is adding heat to the system, but it is doing so on top of decades of human-driven warming. As ocean temperatures continue to rise, the risks to marine ecosystems and coastal communities also increase,” said Samantha Burgess, Strategic Lead for Climate at ECMWF.

The effects of warmer oceans include rising sea levels as seawater expands, more frequent and intense marine heatwaves, and damage to ecosystems such as coral reefs and seagrass meadows. These changes can also disrupt fisheries and aquaculture.

Warmer oceans can transfer more heat and moisture into the atmosphere, potentially intensifying rainfall and some storms. They also become less efficient at absorbing carbon dioxide, potentially weakening an important natural buffer against climate change.

Earlier, Qazinform News Agency reported that a Super El Niño could transform US winter weather.