WMO warns 2027 could set heat record

WMO Secretary-General Celeste Saulo. File photograph, 2025. European Union, 2026 / Xavier Lejeune; cropped, via Wikimedia Commons, CC BY 4.0.

The World Meteorological Organisation (WMO) has warned that a strengthening El Niño could help make 2027 the hottest year recorded, as heat released from the Pacific Ocean adds to the effects of long-term global warming.

The UN agency issued the warning on Monday, 9 November, at the COP31 climate conference in Antalya, Turkey, where it presented its latest assessment of temperatures, ocean conditions and extreme weather.

WMO Secretary-General Celeste Saulo said countries should prepare for the possibility of another annual temperature record. El Niño generally has its greatest influence on global temperatures in the year after it develops, she explained in her conference statement.

The assessment documents substantial human losses from extreme weather during 2026. WMO cited preliminary estimates associating Europe’s heatwaves, drought and wildfires with more than 30,000 excess deaths.

In India, an April heatwave exposed an estimated 146.5 million people to extreme temperatures. A Himalayan glacier collapse and the resulting flash flood killed more than 1,300 people in August, the agency reported.

Saulo warned that El Niño would compound the hazards communities already face as the climate warms. The dpa/NAN account quoted her describing it as a “risk multiplier and heatwaves, tropical cyclones, and rainstorms are intensifying faster than the historical baselines.”

According to that account, Saulo said the developing event could become the strongest since 1950 and continue into 2027.

The dpa/NAN report also described the recurring climate pattern in these terms: “The phenomenon, which occurs every few years, causes extreme weather and rising temperatures.”

John Kennedy, WMO’s head of climate information, said the additional heat and moisture associated with El Niño intensified risks arising from long-term climate change.

He also noted that El Niño events had become more frequent during the 20th and 21st centuries, although he did not attribute that change directly to climate change.

WMO’s measurements put the global average surface temperature for January to September 2026 at approximately 1.47°C above the pre-industrial average, using 1850–1900 as the reference period. The estimate carries an uncertainty of ±0.13°C.

On the available data, the agency expects 2015–2026 to constitute the 12 warmest years in the observational record. The four years from 2023 to 2026 account for the highest temperatures within that period, although the final assessment of 2026 will require full-year observations.

The January–September estimate remains below the 2024 annual record of 1.55°C. WMO nevertheless expects El Niño’s warming influence to lift the figure for 2026 as a whole.

The Paris Agreement’s 1.5°C goal concerns warming sustained over an extended period, typically assessed over 20 years. WMO distinguishes that long-term measure from temperatures recorded during an individual year or part of a year.

The report also identifies changes in the oceans and the world’s ice reserves. Global mean sea level reached a record high in 2026, continuing a rise driven by melting land ice and the expansion of warming seawater.

WMO said part of this year’s increase could reflect El Niño-related changes in rainfall, including a shift from land towards the ocean in the western tropical Pacific.

Glaciers lost more than 400 gigatonnes of ice during 2025, equivalent to approximately one millimetre of global sea-level rise.

The current update includes observations available up to September 2026. WMO plans to publish its final State of the Global Climate 2026 report in March 2027.