Overview
- The fourth annual synthesis, published June 11, 2026 by more than 70 scientists from 17 countries, finds 2025 global mean temperature at 1.39°C above preindustrial levels with 1.37°C of that attributed to human activity.
- Authors say current trends would likely drive the Paris Agreement 1.5°C limit to be crossed around 2030 unless greenhouse gas emissions fall significantly.
- The report attributes recent rapid warming to record fossil fuel emissions together with a drop in aerosol cooling from air pollution controls, which has reduced the temporary masking of heating.
- Key physical indicators worsened: the Earth's energy imbalance is at a record high, global mean sea level rose about 23 cm since 1901 with a current annual rate near 3.84 mm, and annual marine heatwave days more than tripled since 1991 to 65 days in 2025.
- The authors warn that recent public funding cuts and geopolitical choices, including a reported decision by a major funder to pull back ocean financing and reduced support for WMO, WCRP/PMRC and GCOS, could degrade satellite and ocean observation systems and weaken forecasting, adaptation and early‑warning capacity for communities.