Overview
- The daily global sea‑surface temperature reached 21.1 °C on 22 August, the highest value in the ERA5 record used by Copernicus and ECMWF.
- Copernicus’ ERA5 analysis combines satellites, ships and buoys and estimates temperature near 10 meters depth for waters between 60°S and 60°N.
- Scientists say a strong, developing El Niño is adding heat to an already warmed ocean and is forecast to strengthen through late 2026 and possibly into early 2027.
- Warmer seas increase the chance of stronger storms by supplying more heat and moisture to the atmosphere, drive more frequent marine heatwaves, raise sea level by thermal expansion, and strain fisheries and coastal livelihoods.
- Researchers note this August spike is unusual because ocean temperatures normally peak in March–April and warn the record could be broken again if El Niño reaches a higher peak around March–April 2027.