The WMO's latest climate assessment reveals record ocean heat, accelerating sea-level rise and extreme weather, with 2026 among the hottest years ever recorded.
State of the climate 2026: WMO warns of unprecedented climate extremes
“Together, we can save lives. We have no time to lose.”
With these words, Celeste Saulo, Secretary-General of the World Meteorological Organization (WMO), brought scientific evidence to the forefront of the COP31 climate discussions underway in Antalya, Türkiye.
The WMO has released its latest State of the Climate 2026 update, documenting another year of exceptional global temperatures, accelerating ice loss and rising sea levels.
“The science is extremely robust,” Saulo continued. “Once again, we have documented a series of broken records. And current greenhouse gas levels show that there is no end in sight.”
The year 2026 extends a prolonged period of exceptionally high global temperatures, record ice melt and rising seas. According to the WMO report, an exceptionally strong El Niño event is expected to bring further warming and extreme weather conditions well beyond 2027.
State of the climate 2026: Cascading risks for economies, ecosystems and communities
The report highlights cascading risks affecting the environment, economic activity and everyday life.
Ocean heat has reached record levels for the tenth consecutive year, while sea surface temperatures have set new monthly records. Global mean sea level has also reached another peak, increasing risks for approximately 900 million people living in coastal areas.
Together, these developments give the expression “off the charts” an entirely new meaning.
Heatwaves, tropical cyclones and torrential rainfall are intensifying faster than historical benchmarks had anticipated. Their human and economic costs have reached unacceptable levels.
In 2026, millions of people experienced unbearable heat, contributing to tens of thousands of excess deaths in Europe alone.
India, Pakistan and large parts of Asia and North America experienced dangerous heatwaves. The disasters in China and Nepal in August demonstrated the devastating consequences that high-mountain hazards can have for downstream communities.
As COP31 convenes, severe flooding is affecting parts of South America and Africa, while drought continues to affect Asia, the Pacific region and Central America.
The past four years have been the hottest in more than 150 years
The State of the Climate 2026 update confirms that the past 12 years have been the warmest on record, with the four most recent years occupying the top four positions.
The period from 2023 to 2026 represents the four hottest years in more than a century and a half of observations.
Between January and September 2026, the global mean near-surface temperature was approximately 1.47°C above the pre-industrial average.
This anomaly could increase before the end of the year due to the warming influence of El Niño, which intensified from August and could become the strongest event ever recorded by December.
The January-September 2026 temperature anomaly of 1.47°C ± 0.13°C above the 1850-1900 average was comparable to the annual averages recorded in 2025 (1.43°C) and 2023 (1.46°C), but remained below the 2024 record of 1.55°C.
These figures confirm that 2023, 2024, 2025 and 2026 are the four warmest years in the observational record.
Global sea levels reach new highs in 2026
Global mean sea level reached a new record in 2026.
Sea-level rise has accelerated since satellite observations began, driven by melting glaciers and ice sheets, alongside the thermal expansion of warming ocean waters.
June, July and August 2026 recorded the highest sea levels observed since 1993.
Although the long-term rise is primarily associated with ocean warming and ice loss, the particularly sharp increase observed in 2026 may also reflect changes linked to the developing El Niño event.
These include shifts in precipitation from land to ocean areas in the western tropical Pacific.
Sea ice remains below average in both polar regions
Sea ice extent remained predominantly below average in both the Arctic and Antarctic regions.
The findings reflect a particularly serious situation, given the central role sea ice plays in regulating the global climate system and supporting polar ecosystems.
Glaciers lost more than 400 gigatonnes of ice in 2025
In 2025, glaciers worldwide lost more than 400 gigatonnes of ice, equivalent to approximately 1 mm of global sea-level rise, according to the WMO report.
The annual mass loss was equivalent to filling five Olympic-sized swimming pools every second throughout the year.
The year 2025 marked the fourth consecutive year in which all 19 glacier regions worldwide experienced ice loss.
During the 2025 hydrological year, glaciers recorded their sixth-largest annual mass loss since global monitoring began in 1975.
Glacier retreat has serious consequences for local and downstream geological hazards, ecosystems, regional water resources and water quality. It also affects the Earth’s energy balance and global sea levels.
Extreme weather events caused widespread damage between January and August 2026
Extreme weather and climate events have claimed lives, destroyed livelihoods, undermined food security, deepened poverty and contributed to forced displacement across multiple regions.
In Europe, heatwaves, drought and wildfires may have caused more than 30,000 excess deaths, according to preliminary estimates cited by the WMO.
Extreme heatwaves set temperature records in at least eight countries, with substantial consequences for agriculture, energy systems and transport infrastructure.
In India, an estimated 146.5 million people were exposed to extreme heat during the April 2026 heatwave.
In late August, the collapse of a Himalayan glacier triggered catastrophic flash flooding downstream, killing more than 1,300 people and causing severe damage to Nepal’s already fragile economy.
Tropical cyclones also caused widespread destruction and loss of life in numerous countries.
Earth’s energy imbalance continues to increase
Measurements of ocean heat and satellite observations indicate that the Earth’s energy imbalance is growing, with the climate system accumulating heat at an accelerating rate.
In 2025, this imbalance reached its highest observed level since records began in 1960.
Preliminary data covering January to July 2026 suggest that another record may be reached.
Ocean warming provides one of the clearest indicators of the Earth’s energy imbalance because more than 90% of the excess energy is absorbed by the oceans.
In 2025, ocean heat content in the upper 2,000 metres reached its highest level on record, exceeding the 2024 figure by 19 ± 11 zettajoules (ZJ).
Preliminary observations through July 2026 indicate that ocean heat content continued to increase.
Greenhouse gas concentrations reach record levels
Atmospheric concentrations of the three principal greenhouse gases, carbon dioxide, methane and nitrous oxide, reached record levels in 2025, the latest year for which consolidated global data are available.
Compared with pre-industrial levels in 1750:
- Carbon dioxide (CO₂) concentrations increased by 53%.
- Methane (CH₄) concentrations increased by 167%.
- Nitrous oxide (N₂O) concentrations increased by 26%.
Terrestrial ecosystems exchange approximately ten times more CO₂ with the atmosphere than humans emit. However, climate stress and water scarcity can weaken their ability to absorb carbon dioxide, potentially transforming some ecosystems from carbon sinks into carbon sources.
Meanwhile, CO₂ absorbed by the oceans alters marine chemistry, contributing to a long-term decline in surface ocean pH.
This process continued in 2026.
COP31: Early warning systems offer evidence that climate action can deliver results
Despite the increasingly alarming findings in the State of the Climate 2026 report, Celeste Saulo also delivered a message of hope to COP31.
“Our collective efforts are delivering results. The number of countries reporting the presence of multi-hazard early warning systems increased from 56 in 2015 to 136 in 2025. This reminds us that progress is possible when we act together. COP31 needs to deliver urgent decisions capable of mobilising the financing required to address this existential threat that affects us all.”
The expansion of early warning systems demonstrates that coordinated international action can produce measurable results, even as the scale and intensity of climate-related risks continue to grow.
