Overview
- The Oct 2024–Sep 2025 period ran about 1.6°C above the 1991–2020 average, with the warmest Arctic autumn on record, the second-warmest winter, and the third-warmest summer.
- Winter sea ice reached its smallest March maximum in 47 years of satellite data, and about 95% of the Arctic’s oldest, thickest ice has vanished, with September extent remaining among the lowest on record.
- Greenland lost an estimated 129 billion tons of ice in 2025 as increasingly frequent extreme-melt episodes accelerate mass loss, contributing to global sea-level rise and freshening the North Atlantic.
- The Arctic grew wetter and greener, logging record-high spring precipitation and near-record tundra greenness, while widespread permafrost thaw turned more than 200 Alaska watersheds rust-orange with acidic, metal-laden runoff.
- The report highlights risks to critical observing networks from funding and staffing cuts and aging satellites, which could degrade long-term sea-ice and ecosystem records essential for decision-making.