Overview
- The WMO says Earth’s energy imbalance hit its highest level on record in 2025 and has been added as a core climate indicator.
- Over 91% of the excess heat is stored in the ocean, which set a new heat-content record in 2025 as its warming rate more than doubled since 1960–2005.
- Roughly 90% of the ocean surface experienced at least one marine heatwave in 2025, damaging ecosystems and weakening the ocean’s carbon sink.
- The 2015–2025 period was the warmest decade on record, with 2025 ranking second or third warmest, and global sea level about 11 cm higher than in 1993 after an accelerated rise.
- Greenhouse gas levels reached multi‑millennial highs, driving extremes that killed thousands and affected millions in 2025, while scientists continue to debate whether surface warming has recently sped up.