A World Meteorological Organization (WMO) report warns that the planet’s climate is now more out of balance than at any time in the observational record, with effects likely to persist for centuries to millennia. The State of the Global Climate 2025 synthesizes temperature, ocean, cryosphere and extreme-event data and highlights accelerating, long-lived changes driven by rising greenhouse gas concentrations.
Top findings
– 2015–2025 was the hottest decade on record.
– Oceans recorded unprecedented warmth for a ninth straight year.
– Glaciers and sea ice continued to shrink, and polar ice was among its lowest on record.
– Extreme weather, cascading health risks and economic losses increased.
– Earth’s energy imbalance reached a record high: more solar energy is entering the climate system than is escaping.
– Global mean sea level has been rising faster since 2012 than during the two preceding decades.
Context and drivers
Depending on the dataset used, 2025 ranked either the second- or third-warmest year on record, about 1.43°C above pre‑industrial levels—slightly cooler than 2024’s 1.55°C, in part because of a short-term La Niña influence. The dominant long-term driver is increasing greenhouse gases from fossil fuel combustion. Atmospheric CO2 reached its highest concentration in at least two million years in 2024 and continued to climb in 2025. Scientists also caution that a return of El Niño in 2026 could push temperatures higher and amplify extremes.
Human and economic impacts
The report documents widespread impacts in 2025: heatwaves, wildfires, floods, droughts and tropical cyclones caused thousands of deaths and produced billions of dollars in losses. California wildfires in January 2025 alone caused more than $60 billion in damages, the costliest wildfire event on record.
Health and displacement effects are increasing. Dengue has become the fastest-growing mosquito-borne disease, and an estimated 1.2 billion workers face dangerous heat exposure each year. Climate-driven crop failures, water stress and weather-related disasters have contributed to hunger, migration and instability; roughly 250 million people were displaced by weather-related events over the past decade. The UN warns that the climate crisis also intersects with conflict and security issues, while military activity contributes significant emissions.
Energy imbalance and lasting warming
For the first time the WMO included Earth’s energy imbalance—the difference between incoming solar radiation and outgoing heat—as a core indicator. That imbalance reached an all-time high in 2025. Greenhouse gases act like a blanket, trapping extra energy: about 91% of that excess has been absorbed by the oceans, 5% by land, 3% by ice and glaciers, and roughly 1% has warmed the atmosphere. Because so much heat is stored in the oceans and other components, many changes—particularly ocean warming and sea level rise—are effectively irreversible on centennial to millennial timescales even if emissions are reduced now.
Oceans and cryosphere
Oceans, the planet’s primary heat sink, set new heat records again. Around 90% of the ocean surface experienced at least one marine heatwave in 2025, and warming is penetrating into deeper layers. Warmer seas are bleaching coral, reducing fish stocks, weakening the ocean’s capacity to absorb CO2, intensifying storms and speeding polar ice loss—all contributors to continuing sea level rise. Glacier mass loss in 2025 was among the five worst years since comprehensive records began in 1979.
Policy and preparedness
The WMO report does not prescribe policy choices but aims to inform governments, businesses and communities so they can better prepare for growing climate risks. Integrating weather and climate data into health, disaster-response and infrastructure planning can improve early warning, reduce impacts and save lives. As WMO Secretary-General Celeste Saulo observed, observing and understanding current conditions is essential to protect the future.
The report underscores that rapid, deep emissions cuts alongside investment in adaptation and preparedness are needed to limit further damage and reduce long-term risks.