Earth's energy imbalance is increasing, with the planet accumulating heat at an accelerating rate. The imbalance has reached its highest level since monitoring began, as greenhouse gas emissions trap unprecedented amounts of heat and disrupt the natural balance between incoming solar energy and outgoing radiation.
The ocean absorbs around 90 per cent of this excess heat, and 2026 is on track to become the tenth consecutive year of record-high ocean temperatures.
Sea levels have reached their highest levels on record, while sea-surface temperatures also registered monthly records during 2026. The long-term retreat of glaciers continues, with the annual ice mass lost in 2025 equivalent to filling five Olympic-sized swimming pools every second throughout the year. Meanwhile, global freshwater storage has been declining since 2014.
"We have entered a new age of climate extremes. A supersized El Niño is colliding with a planet already superheated by man-made climate change. Climate records keep falling. The human costs keep rising. And those least responsible are suffering first and worst. Leaders must get serious by cutting emissions faster, accelerating a just transition from fossil fuels and delivering the finance and protection vulnerable countries need," UN Secretary-General António Guterres said.
WMO Secretary-General Celeste Saulo said the El Niño phenomenon and the state of the global climate in 2026 had taken the situation to unprecedented levels.
"El Niño doesn't add new heat to the planet. It releases heat from the ocean, which is the warmest ever measured. There is simply more heat available to release," Saulo said.
She warned that climate change, combined with El Niño, would amplify extreme weather events, including heatwaves, tropical cyclones and rainstorms.
"We are supercharging our weather and El Niño will be a risk multiplier. Heatwaves, tropical cyclones, and rainstorms are intensifying faster than our historical baselines prepared us for. Hundreds of millions of people this year have been exposed to unbearable extreme heat, whilst the catastrophic ice and rock collapse and flash floods in Nepal highlighted the compound risks facing communities in fragile, warming high-mountain terrain," she added.
The WMO stressed that forecasts based on sustained observations from across the world are becoming increasingly important to monitor the rapidly changing climate and help societies and economies prepare for growing risks.
However, there has been some progress in climate preparedness. The number of countries reporting the existence of multi-hazard early warning systems (MHEWS) increased from 56 in 2015 to 136 in 2025, according to the report.
The WMO State of the Climate 2026 Update was released on the opening day of COP31 in Antalya, Türkiye. The science-based assessment includes data available up to September 2026 and therefore does not capture the most recent impacts of El Niño.
The final State of the Global Climate 2026 report is scheduled for release in March 2027. It will incorporate scientific contributions from dozens of National Meteorological and Hydrological Services, regional climate centres, United Nations partners and experts from the WMO community.