Overview
- The increase equals roughly 37 years of global primary energy use at 2023 levels, underscoring the scale of accumulation.
- The assessment merges independent datasets (IAP, Copernicus Marine, NOAA/NCEI) with a reanalysis (CIGAR-RT) and extensive Argo float measurements to 2,000 meters.
- Global sea-surface temperature ranked about third warmest in 2025, roughly 0.5°C above the 1981–2010 average, with a slight dip linked to a shift from El Niño to weak La Niña.
- Heating was uneven, with hotspots in the tropical and South Atlantic, the North Pacific and Indian Ocean, the Mediterranean, and the Southern Ocean; about 16% of ocean area set local records and 33% was in the top three.
- Scientists highlight consequences already unfolding—higher seas, stronger downpours and cyclones, prolonged marine heatwaves and coral bleaching—and warn ocean heat will keep climbing until emissions are cut.