Scientists Say Scorching Temperatures Brought on by the ‘Super’ El Niño Could Kill Nearly Half a Million People by February

The predicted number, which includes deaths since June, likely represents an underestimate of total deaths. The heat could linger beyond February, and the climate swing could bring about other life-threatening conditions, including flooding, wildfire and infectious diseases

Sara Hashemi | Daily Correspondent

September 24, 2026 10:00 a.m.

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Extreme heat caused by the “super” El Niño currently brewing in the Pacific Ocean could cause nearly half a million deaths by the end of February.

The estimate, described in a report released in September by the University of Chicago’s Climate Impact Lab, found that people living in the Global South will be hardest hit. Although the work has not been peer-reviewed, the authors say their findings are urgent enough to publicize prior to formal publication. They plan to submit it to a scientific journal, and in the meantime, they hope that it can guide humanitarian and government decisions in the coming months to avoid some of the predicted deaths.

“We’re hoping this information is actionable, that decisions can be made to move resources ahead of time,” says Emily Grover-Kopec, a director at the research organization Rhodium Group who worked on the report, to Michael Le Page at New Scientist. That could involve the implementation of heat warnings, health outreach to vulnerable populations and cooling and hydration centers.

The projection is based on the Climate Impact Lab’s previous research looking at the relationships between temperature and additional heat deaths in more than 24,000 regions worldwide. The connections were then applied to the temperature anomalies expected to be brought on by the current El Niño climate swing, which began in June and will extend through February. Since it started, the team estimates excess heat has caused more than 200,000 deaths.

Overall, the researchers predict about 451,000 heat-related deaths during the entire El Niño event. That means hundreds of thousands of lives are at risk over the next several months.

Africa’s Sahel region, a semi-arid zone that stretches across the continent just south of the Sahara Desert, is expected to be most affected. There, excess heat could kill an additional 66,800 people from September through February compared with a normal year. Almost half of those deaths are attributed to Nigeria, according to the report, and Sudan, Niger, and Chad are also facing high fatalities.

South and Southeast Asia will also be severely impacted. In the coming months, the researchers project 19,300 additional deaths in Indonesia; 15,800 in India; and 19,400 collectively in the Philippines, Vietnam, Thailand and Cambodia.

“People have been able to forecast when there’s going to be shocks to crops, and give advance warning of that,” says report co-author Michael Greenstone, an economist at the University of Chicago and co-founder of the Climate Impact Lab, to Damian Carrington at the Guardian. “This new report is opening the door to being able to do it for an even more important outcome—I would say the most important outcome—which is death.”

Greenstone, Grover-Kopec and their colleagues call the El Niño a “postcard from the future.” It is forecasted to help raise global temperatures by 2.1 degrees Fahrenheit above normal in the next few months. Climate change is expected to bring a similar heat increase in 20 years.

“Mortality projections for the near term provide a signal of where we are headed if new adaptation investments do not materialize,” the researchers write in the report.

The number of deaths might rise beyond the estimate, they add, since the scorching temperatures caused by El Niño could linger into June and July of next year. What’s more, the report looked only at mortality related to heat.

“El Niño influences wildfire in Indonesia, infectious disease in South America, flooding in the western U.S. and so on,” says Christopher Callahan, a climate scientist at Indiana University Bloomington who wasn’t involved in the work, to New Scientist. “So, the total death toll may be higher.”

Sara Hashemi is a science writer and fact-checker currently based in New York City. Her work has appeared in Sierra, The Body, Maisonneuve magazine and more.