Highest-ever ocean temperature measured as powerful El Niño forms

Scientists have recorded the highest ever temperature in the world's oceans, as climate change merges with an intense El Niño in the Pacific. The global ocean surface temperature peaked at a record 70 degrees Fahrenheit on August 22, according to Europe's Copernicus Earth observation agency, which has been monitoring the reading since 1979.

The previous peak occurred in March 2024. Dr. Samantha Burgess, Copernicus' strategic lead for climate, explained that El Niño is adding more heat to the system, but on top of the warming caused by human activities. As ocean temperatures keep rising, the risks to marine life and coastal areas increase, she warned. Higher ocean temperatures lead to sea level rise and make extreme weather events more likely, as warmer water carries more heat and moisture to the atmosphere, intensifying storms and heat on land.

Warmer oceans also have less ability to soak up carbon dioxide. Record temperatures have already been observed in specific regions of the oceans, such as the western Mediterranean Sea and Earth's poles, mainly due to human-induced climate change. Copernicus anticipates this trend to persist, with ocean temperatures now being amplified by El Niño.

The August record is especially concerning as global ocean temperatures usually peak in March and April, following the Austral summer, Copernicus noted.