El Nino-Driven Heat Could Cause 451,000 Extra Deaths by February, Study Warns

Record global heat driven by a powerful El Nino, compounded by severe droughts, wildfires and shrinking water supplies, could cause nearly half a million additional deaths worldwide by the end of February, a research report released Wednesday estimates.

The Climate Impact Lab, based at the University of Chicago, projects as many as 451,000 extra heat-related deaths between June and the end of February compared with what would be expected in a typical year. The estimate covers the full El Nino period, running from June 2026 to the end of February 2027.

The burden is expected to fall most heavily on poorer countries already grappling with food insecurity and high energy costs, pressures linked partly to climate change and the fallout of the war in Iran.

Michael Greenstone, a co-founder of the group and a co-author of the study, said the danger is unlikely to fade when the El Nino ends. Its effects could persist well into next summer, he said, adding that heat is most dangerous in places that are already hot and relatively poor.

"If you're already in a hot place, the extra couple of degrees are going to be much more dangerous," Greenstone said. Wealthier places, he noted, generally have greater access to air conditioning, reliable water supplies and functioning health systems.

The study combined seasonal temperature forecasts with localized estimates of how high temperatures affect mortality across more than 24,000 regions worldwide. Researchers compared deaths expected under El Nino-driven high temperatures with deaths expected if temperatures had stayed similar to the past three decades.

The report warns that the Global South — a reference to developing countries rather than a geographical region — will bear the heaviest burden. The Sahel, the semiarid belt along the southern fringe of the Sahara Desert, is expected to be the hardest-hit area, with about 66,800 additional deaths.

Other major hot spots include South and Southeast Asia and parts of Latin America. The researchers project about 19,400 additional heat-related deaths across the Philippines, Vietnam, Thailand and Cambodia, along with 19,300 in Indonesia, 15,800 in India and 13,300 in Brazil.

The report recommends measures governments can take, including heat-warning systems, cooling centers, hydration stations, protections for outdoor workers, expanded hospital capacity and targeted outreach to elderly people and other vulnerable groups. The authors also call for anticipatory financing so governments can move resources before dangerous heat peaks.

Abhiyant Tiwari, a heat expert at NRDC India who was not involved in the study, said the projections should serve as a call to action rather than a reason for alarm. While India has well thought-out plans, implementing them and raising needed funds remains a challenge, he said.

"The real measure of our preparedness is not how many heat warnings we issue, but how effectively we protect people and reduce preventable deaths," Tiwari added.

El Nino is a natural climate pattern, but this year's unusually strong event is unfolding on a planet already warmed by human-caused climate change, raising the risks from extreme heat. The Climate Impact Lab said global land temperatures during this El Nino could be about 1.2 degrees Celsius (2.1 Fahrenheit) higher, producing 44% more extremely hot days than in a typical year.

The report said those temperature increases may mirror conditions that climate change could make common some 20 years from now, making this El Nino a possible preview of what lies ahead as the planet warms. It also presents an opportunity for decision-makers "to see exactly where emergency actions can be taken now to save tens of thousands of lives," the authors said.