The World Meteorological Organisation (WMO), a UN agency, has warned that 2027 could become the hottest year on record as a developing El Niño threatens to intensify global temperatures and extreme weather.
The warning came on Monday as world leaders gathered in Turkey for the UN Climate Change Conference (COP31).
WMO Secretary-General Celeste Saulo said the climate phenomenon could worsen existing weather risks, including heatwaves, tropical cyclones and heavy rainfall.
“El Niño acts as a risk multiplier, and heatwaves, tropical cyclones, and rainstorms are intensifying faster than the historical baselines,” she said.
A new WMO climate report showed that each of the last 12 years was among the warmest since records began, with the last four ranking as the four hottest.
The report put the global average surface temperature between January and September 2026 at about 1.47 degrees Celsius above pre-industrial levels.
It noted that the margin of uncertainty was 0.13 degrees Celsius, meaning the global temperature could have crossed the critical 1.5-degree threshold. The world last exceeded that level in 2024.
The agency said extreme weather events had caused widespread devastation this year, with preliminary estimates indicating that heatwaves, drought and wildfires in Europe resulted in more than 30,000 excess deaths.
Extreme heat in India in April affected 146.5 million people, while more than 1,300 people reportedly died in a glacier collapse and flash flood in the Himalayas in August.
The report also showed that global mean sea level reached a record high in 2026. WMO experts said the rise could partly be linked to El Niño, which shifts rainfall from land to the ocean.
Saulo said the developing El Niño was expected to continue into 2027 and could become the strongest since 1950.
WMO Head of Climate Information John Kennedy said the additional heat, energy and moisture associated with the phenomenon would compound the risks posed by long-term climate change.
He noted that El Niño events had become more frequent in the 20th and 21st centuries but said he was not directly linking the trend to climate change.
The report also said glaciers worldwide lost more than 400 gigatonnes of ice in 2025, contributing about one millimetre to global sea-level rise.
