Highest-ever ocean temperature measured as powerful El Niño forms

On August 22 the global average sea-surface temperature reached a record 70 °F, the highest daily value since Copernicus began daily monitoring in 1979, driven by a strong El Niño overlaying decades of anthropogenic warming. The heat surge threatens marine ecosystems, raises sea-level rise risk, and amplifies extreme weather by transferring more heat and moisture to the atmosphere while diminishing the ocean’s capacity to absorb CO2.