Strengthening El Niño poses growing global health threat, UN warns
GENEVA, Switzerland — The World Health Organization (WHO) and the World Meteorological Organization (WMO) warned on Tuesday (September 22) that a rapidly strengthening El Nino weather pattern poses growing risks to global health, with impacts expected to intensify into 2027 as record temperatures and extreme weather strain vulnerable communities.
“El Nino is a significant public health threat, not just a climate phenomenon,” Teresa Zakaria, head of WHO’s Risk Reduction, Humanitarian Operations and Climate Change Unit, told reporters in Geneva.
She said the weather pattern acts as a “risk multiplier”, increasing extreme weather and altering disease risks, with the heaviest impacts likely where climate shocks overlap with weak health systems, food insecurity and humanitarian crises.
The warning comes as El Nino develops against a backdrop of record global heat. Armel Castellan, WMO’s Extreme Heat Services Technical Advisor, said the phenomenon was strengthening rapidly after the world experienced its two hottest months on record and record sea-surface temperatures.
“The effects of El Nino are already being felt in climate-sensitive sectors and they will grow,” Castellan said, adding that while the event was forecast to peak towards the end of 2026, “the impacts will run well past it.”
WHO said health risks linked to El Nino include heat-related illnesses, respiratory diseases associated with wildfire smoke, malnutrition, cholera and the spread of mosquito-borne diseases such as malaria and dengue.
Zakaria said droughts and floods could destroy homes and livelihoods, displace populations and reduce access to food, clean water and healthcare.
“They also create conditions that allow diseases to spread,” she said.
Malnutrition and cholera were among the most serious concerns in both drought- and flood-affected areas, she added, noting that more than 150 million people already face acute food insecurity worldwide, a figure expected to rise as climate-related shocks disrupt food production.
WMO forecasts for September through November point to above-normal rainfall in some regions and drought in others, raising concerns over water security, nutrition and vector-borne diseases alongside extreme heat.
Castellan said this El Nino was unusual because it was occurring on top of already record-breaking temperatures. As the event peaks late in 2026, parts of the Southern Hemisphere, including southern Africa, South America and Australia, will enter their hottest season, heightening the risk of drought, wildfires, smoke and air pollution in early 2027.
Both agencies urged governments to use seasonal forecasts and strengthen preparedness measures, including disease surveillance, early warning systems and the pre-positioning of medical supplies in high-risk areas.