Overview
- The 10th Copernicus Ocean State Report, published Sep. 30, 2026, finds the rate of ocean warming has doubled over two decades and sea-surface temperatures set new records in 2023–2026.
- In 2025 the oceans absorbed a record additional 23 zettajoules of heat, marking the ninth straight year of record heat uptake and amplifying marine heatwaves and storm energy.
- Global mean sea level has risen about 3.8 mm per year since 1999 with acceleration since 2012, increasing flood, erosion and infrastructure risk for hundreds of millions in coastal and island communities.
- Ocean chemistry and ecosystems are degrading as acidity has risen roughly 17% since 1985, coral bleaching affected more than four-fifths of reefs between 2023–2025, and polar ice loss has driven breeding failures for ice-dependent species.
- The report urges permanent, sustained ocean monitoring to give governments and communities timely forecasts and adaptation tools to prepare for accelerating ocean-driven hazards.