Nairobi — The period from 2015 to 2025 has been the hottest 11-year stretch on record, with Earth's climate system increasingly out of balance due to rising greenhouse gas emissions, the World Meteorological Organization (WMO) said in a report released Monday.
The UN weather agency's flagship State of the Global Climate 2025 report found that 2025 ranked among the second or third warmest years in the 176-year observational record, with global temperatures about 1.43°C above the 1850-1900 pre-industrial average.
"The state of the global climate is in a state of emergency. Planet Earth is being pushed beyond its limits. Every key climate indicator is flashing red," said António Guterres, warning that humanity has "just endured the eleven hottest years on record."
"When history repeats itself eleven times, it is no longer a coincidence. It is a call to act," he added.
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The report was released on World Meteorological Day, marked annually on March 23, under the 2026 theme "Observing Today, Protecting Tomorrow."
According to the WMO, Earth's climate is now "more out of balance than at any time in observed history."
Concentrations of heat-trapping greenhouse gases--carbon dioxide, methane and nitrous oxide--have reached their highest levels in at least 800,000 years, disrupting the planet's natural energy balance.
For the first time, the report includes Earth's energy imbalance as a key climate indicator, measuring the difference between incoming solar energy and the energy leaving the Earth system.
Scientists say this imbalance has risen steadily since records began in 1960 and reached a new high in 2025.
"Scientific advances have improved our understanding of the Earth's energy imbalance and of the reality facing our planet and our climate right now," said WMO Secretary-General Celeste Saulo.
"Human activities are increasingly disrupting the natural equilibrium, and we will live with these consequences for hundreds and thousands of years," she added.
Extreme weather events linked to rising temperatures caused widespread disruption in 2025, including heatwaves, wildfires, droughts, storms and flooding, resulting in thousands of deaths and billions of dollars in losses.
Oceans continue to absorb most of the excess heat from global warming, with more than 91 percent of the additional heat stored in the ocean. They also absorb large amounts of carbon dioxide.
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Ocean heat content reached another record high in 2025, extending a streak of annual records over the past nine years.
The rate of ocean warming between 2005 and 2025 has more than doubled compared with the period from 1960 to 2005, the report said.
Melting ice is also accelerating climate impacts. Arctic sea ice levels in 2025 were at or near record lows, while Antarctic sea ice ranked among the lowest ever recorded.
Glaciers worldwide continued to lose mass, with significant losses reported in Iceland and along the Pacific coast of North America.
Rising ocean temperatures and melting ice are driving long-term global sea level rise, which has accelerated since satellite measurements began in 1993.
The report warns that many of these changes--including ocean warming, sea-level rise and deep-ocean acidification--will continue for centuries, according to projections by the Intergovernmental Panel on Climate Change (IPCC).
