Overview
- On June 21 Copernicus datasets showed global average sea-surface temperatures reached about 20.86–21.0°C, surpassing the previous June highs set in 2023 and 2024.
- Researchers attribute the spike to a developing El Niño together with persistent anthropogenic warming, a combination that pushes more heat to the ocean surface and into the atmosphere.
- Copernicus reported widespread marine heatwaves affected roughly 82% of the global ocean in the first half of 2026, with extreme regional hotspots in the Mediterranean and the tropical Pacific.
- Warmer seas increase the fuel for stronger storms, heavier rainfall, and more intense heatwaves, and they drive coral bleaching, fisheries stress and faster sea-level rise that directly affect coastal communities.
- Independent Copernicus services (C3S and CMEMS) and agencies such as NOAA and NASA back the finding, scientists warn records may continue into late 2026 and 2027, and they call for sustained funding of ocean monitoring and seasonal forecasts.