Supersized El Niño Could Be Strongest Ever, 50 Million at Risk

The World Meteorological Organization warned on September 3 that El Niño is set to intensify into a "very strong" event, peaking toward the end of 2026. Forecasts from the agency's Global Producing Centres show a near-100 percent likelihood that the phenomenon will persist through February 2027, according to the agency's press release.

It is the first time the UN weather agency has expressed such a degree of certainty about El Niño, WMO Secretary-General Celeste Saulo told a Geneva press conference. A new inter-agency report published September 17 by the Global ENSO Analysis Cell warns that the humanitarian consequences could be enormous: World Food Programme estimates suggest up to 50 million people globally could be affected over the next six to nine months, according to the report posted on ReliefWeb.

Pacific heat running off the charts

The measurements show how quickly the event is developing. The Nino 3.4 index, a closely watched measure of ocean temperatures in the central tropical Pacific, averaged 1.5 degrees Celsius above normal from May through July. By July it had reached 2 degrees, and weekly readings from late July through mid-August climbed as high as 2.6 degrees, according to UN News.

The heat extends well below the surface. In some parts of the Pacific, subsurface temperatures in July and early August were more than 8 degrees Celsius above normal, indicating a huge pool of warm water that will keep feeding the event. Pacific Ocean temperatures in this year's El Niño are already more than 2 degrees Celsius above normal, placing it in the top "very strong" bracket. Only four El Niño events since records began in 1950 have reached that category.

"If this trajectory continues, it may be stronger than anything since our monitoring began. So literally off the charts we have used for the past four decades," Saulo said at the press conference, as reported by BusinessWorld. UN Secretary-General Antonio Guterres said: "El Niño is being supersized before our eyes. The science leaves no room for doubt: the planet is in uncharted waters, and those waters are heating up."

What forecasters expect through 2027

For September through November, WMO multi-model forecasts indicate above-normal temperatures across nearly all land areas, alongside rainfall patterns showing the classic atmospheric response to a strong Pacific El Niño. That means greater chances of heavy rain and flooding in some places and drought in others, according to the agency's Global Seasonal Climate Update.

Other climate drivers could complicate that picture. A positive phase of the Indian Ocean Dipole is expected to develop, reaching a seasonal mean value of 0.9 degrees Celsius. The equatorial Atlantic is forecast to remain unusually warm, with sea surface temperatures in both the North and South Tropical Atlantic staying above normal. The WMO cautions that the strength of the global event does not translate directly into the scale of impacts in any individual country or region.

The forecast has prompted an unprecedented response. It is the first time the World Health Organization has launched a mobilization of this scale with national meteorological and hydrological services, seeking to strengthen forecasts and early-warning systems as the risks mount. The effort is intended to help governments and humanitarian organizations prepare for effects on particularly vulnerable sectors, including agriculture, public health, energy and water supplies, according to UN News.

Why the humanitarian risk is so high

Saulo told reporters: "El Niño means 'little boy' in Spanish, but it has the potential to deliver a massive blow to communities and economies around the world. We are already seeing the disruption and devastation caused by droughts and floods, and we expect these impacts to worsen as El Niño intensifies."

The inter-agency report warns that the emerging risks must be understood alongside conflict, displacement, high food insecurity and high food prices, malnutrition, disease outbreaks, economic pressures and overstretched essential services. It says these conditions have not improved since the previous update in June. In many places, repeated shocks have depleted household assets, increased debt and weakened the coping mechanisms people would ordinarily rely on when drought, floods or high prices affect their livelihoods.

Scientists have not established that man-made climate change is increasing or intensifying El Niño itself. But this El Niño is developing against an unusual backdrop: the oceans are already exceptionally warm, providing a hotter baseline. A warmer atmosphere and ocean can amplify some of its consequences, increasing the heat and moisture available to fuel extreme weather.

The powerful 2023/2024 El Niño contributed to 2024 being the warmest year on record, and Saulo said the record could fall again as this event peaks. "This exceptional El Niño demands exceptional preparedness and response," she said. "We should not be surprised if this record is broken. WMO will be closely monitoring global temperatures in the months ahead."