The UN's weather agency says Earth is accumulating heat faster than ever recorded, creating an unprecedented imbalance that is already reshaping the climate.
Experts point to rising greenhouse gas levels as the main driver of this extra trapped energy, which last year pushed ocean and ice measurements to new extremes.
The World Meteorological Organization reports that the past 11 years are the warmest since records began in 1850.
Global average air temperatures in 2025 sat about 1.43°C above pre‑industrial levels.
A natural La Niña phase helped make 2025 slightly cooler than 2024, when El Niño boosted temperatures.
Still, 2025 remained among the three hottest years on record.
More than 90% of the planet’s excess heat has gone into the oceans.
The top 2 km of the global ocean reached a new high in heat content last year, and ocean warming over the last two decades is occurring more than twice as fast as in the late 20th century.
Surface ice is also declining.
Provisional data show 2024/25 was one of the five worst years on record for glaciers, while sea ice at both poles stayed near record lows through most of 2025.
Carbon dioxide concentrations are now at levels not seen for at least two million years, the WMO says, and scientists link that rise directly to burning fossil fuels.
The agency warns these changes intensify extreme events and expand health risks.
For example, a blistering early‑season heatwave in the southwestern US recently saw temperatures top 40°C—10–15°C above normal—and rapid analysis found the heat’s severity would have been virtually impossible without human influence.
Looking ahead, forecasters expect a transition to El Niño is likely in the second half of 2026.
Combined with the long‑term warming trend, an El Niño event could lift global temperatures to new records into 2027.
UN Secretary‑General António Guterres urged nations to accelerate the move from fossil fuels to renewable energy to protect climate, energy and national security.
WMO officials stress the disruption we are causing will be felt for centuries unless emissions are cut.
The message is clear: without rapid reductions in greenhouse gases and stronger adaptation measures, the world should prepare for more intense heat, melting ice, and other climate impacts in the years ahead.
