Global sea surface temperatures reach record high

On August 22, 2026, the global average daily sea surface temperature reached a new record high of 21.1°C, according to data from the Copernicus Climate Change Service (C3S). This figure surpassed the previous all-time record of 21.09°C set in March 2004, as well as the previous August record of 20.98°C recorded in 2023.

Experts note that while daily fluctuations occur, this milestone is consistent with the ongoing long-term warming of the global ocean, compounded this year by an extreme El Niño phenomenon in the tropical Pacific. The timing is considered unusual, as ocean temperatures typically peak in March and April following the southern hemisphere summer. The record follows a series of monthly heat benchmarks observed throughout 2026.

Oceans absorb over 90% of excess heat generated by carbon dioxide emissions from fossil fuels. This ongoing warming causes sea levels to rise through thermal expansion and provides additional energy to the atmosphere, potentially intensifying storms and heavy rainfall. Furthermore, rising temperatures contribute to more frequent and prolonged marine heatwaves, which threaten marine biodiversity and communities reliant on fishing and coastal resources.