Overview
- Copernicus reported the global extra‑polar daily sea surface temperature hit 21.1°C on Aug. 22, narrowly surpassing the previous single‑day record of 21.09°C from March 2024.
- Scientists attribute the record to an intensifying El Niño adding heat on top of decades of human‑driven ocean warming, with the ocean having absorbed more than 90% of excess heat from greenhouse gases and baseline SSTs roughly 0.8°C higher than pre‑industrial levels.
- Forecast agencies including NOAA, the Met Office and the WMO place very high odds — over 90% in some forecasts — on a very strong or 'super' El Niño that could peak in late 2026 to early 2027.
- The heat is already raising risks: roughly 40–46% of the ocean is in marine heatwave conditions, which stress coral and fisheries (notably the Peruvian anchovy), reduce oxygen and carbon uptake, and can amplify storms, rainfall and sea‑level rise with consequences for coastal communities and food systems.
- Copernicus’s estimate combines satellites, buoys and ship measurements sampled near 10 m depth across 60°S–60°N, and scientists stress continued monitoring is needed because regional impacts and provisional claims about millennial‑scale highs require further analysis and peer review.