The World Meteorological Organization (WMO) has confirmed that 2025 was one of the three warmest years ever recorded, reinforcing scientific warnings that human-driven climate change continues to dominate the global climate system, even when natural cooling influences are present.
In a press release issued by the UN’s specialised weather agency, the WMO reported that global average surface temperatures in 2025 were approximately 1.44°C above the pre-industrial baseline of 1850–1900. The estimate, based on a consolidated analysis of eight leading international datasets from institutions including NASA, NOAA, the UK Met Office and the European Centre for Medium-Range Weather Forecasts, places 2025 firmly among the hottest years in the 176-year instrumental record.
Two datasets ranked 2025 as the second-warmest year globally, while the remaining six placed it third. The absolute global mean temperature for the year was estimated at about 15.08°C. This positions 2025 just behind 2024, the warmest year on record, and in close competition with 2023. Together, the years 2023, 2024 and 2025 represent the warmest three-year period ever observed across all datasets.
The WMO noted that the three-year average temperature anomaly now stands at about 1.48°C above pre-industrial levels, uncomfortably close to the 1.5°C warming limit set under the 2015 Paris Agreement, which is assessed over longer time frames. Alarmingly, the past 11 years, from 2015 to 2025, are now confirmed as the 11 warmest years ever recorded.
La Niña could not offset long-term warming
What makes the 2025 ranking particularly striking is that the year both began and ended under the influence of La Niña, a natural climate phenomenon typically associated with cooler global temperatures. Despite this cooling tendency, global temperatures remained exceptionally high.
WMO Secretary-General Celeste Saulo emphasised that this underscores the overwhelming impact of accumulated greenhouse gases in the atmosphere. She said that while La Niña exerted a temporary dampening effect, it was no match for the long-term warming driven by fossil fuel combustion, deforestation and industrial emissions.
According to the WMO, the persistence of high temperatures during a La Niña year demonstrates how deeply entrenched the warming trend has become, with natural variability no longer able to counteract the underlying human influence on the climate.
Oceans absorbing record levels of heat
The world’s oceans, which absorb roughly 90 per cent of the excess heat generated by global warming, showed equally troubling signs. Ocean heat content in the upper 2,000 metres increased by an estimated 23 zettajoules from 2024 to 2025 an amount of energy roughly equivalent to 200 times the world’s total electricity generation in 2024.
Annual mean sea surface temperatures ranked as the third-warmest on record, despite La Niña conditions. Regionally, about one-third of the global ocean experienced temperatures among the top three warmest observed since 1958, while more than half ranked within the top five. Particularly intense warming was recorded in the tropical and South Atlantic, the Mediterranean Sea, the North Indian Ocean and the Southern Ocean.
Scientists warn that rising ocean temperatures have far-reaching consequences, affecting marine ecosystems, accelerating sea-level rise and altering global weather patterns.
Extreme weather intensified worldwide
According to the WMO, the elevated temperatures on land and sea helped fuel a wide range of extreme weather events in 2025. Severe heatwaves affected multiple continents, heavy rainfall triggered devastating floods, and intense tropical cyclones caused widespread destruction and loss of life.
The organisation stressed that these events highlight the urgent need for robust and accessible early warning systems, especially for vulnerable populations. Early warnings, the WMO said, can significantly reduce fatalities and economic losses by giving communities time to prepare for climate-related hazards.
A continuing climate crisis
UN News coverage of the findings described the 11-year streak of record warmth as a continuing global crisis. Ocean warming, in particular, reflects the long-term accumulation of heat within the climate system, with implications that extend well beyond individual years.
While the WMO’s full State of the Global Climate 2025 report, due for release in March 2026, will provide deeper analysis of greenhouse gas concentrations, ice loss and other indicators, the preliminary data already points to escalating risks. Experts warn that even small increases in global temperatures amplify impacts on ecosystems, economies and human health.
Looking ahead, scientists caution that 2026 could also rank among the warmest years on record, depending on how the El Niño–Southern Oscillation evolves later in the year.
As Celeste Saulo noted, authoritative climate information is now “more important than ever” for turning scientific knowledge into effective action. The confirmation of 2025’s extreme warmth serves as both a sobering record and a stark warning: without rapid emissions reductions and strengthened climate resilience, the world is moving ever closer to dangerous and irreversible thresholds.