A Powerful El Nino Could Cause 450,000 Extra Heat Deaths

More than 450,000 people are projected to die from additional heat linked to an unusually strong El Nino over the next six months, through February 2027. The estimate was published by the University of Chicago's Climate Impact Lab and reported on Sept. 23, 2026 Al Jazeera.

The projection compares El Nino-linked heat deaths with deaths expected in a typical year. El Nino, a natural warming of water in the central and eastern Pacific that shifts weather patterns worldwide, is expected to raise global land temperatures by about 1.2 degrees Celsius (2.1 degrees Fahrenheit). Extremely hot days are projected to be 44 percent more frequent than in an average year.

The toll is concentrated in the tropics and subtropics. The report projects about 66,800 additional deaths across Africa's Sahel region, the belt south of the Sahara. Nigeria has the highest projected country toll at 31,400 additional deaths, followed by Indonesia at 19,300 and Sudan at 17,600. The Philippines, Vietnam, Thailand and Cambodia combined are forecast to see 19,400 extra deaths. India is projected to see 15,800 extra deaths and Brazil 13,300. The authors expect the heaviest toll in poorer countries already struggling with food insecurity and high energy costs.

The physical driver began developing in June and is expected to be one of the strongest El Nino events ever. The U.N. weather agency reported in early September a 100 percent likelihood that El Nino will continue through February 2027. Researchers say its dangers could linger into mid-2027.

Forecast guidance has hardened through September. On Sept. 10, a U.S. forecaster said there was more than 90% risk of a very strong El Nino Reuters. That outlook put a 75% chance on the October-December 2026 season producing a historic event exceeding the strength of previous El Nino events. On Sept. 3, the World Meteorological Organization said the phenomenon is set to intensify further and persist into 2027, potentially the strongest ever recorded, with rising risks of extreme weather Reuters. The WMO had warned earlier that 2027 could be the hottest year since records began due to the combination of climate change and El Nino. A Brazilian scientist had also warned that the El Nino expected in the second half of 2026 could break records and hit southern Brazil.

The broader context here is distribution rather than scale alone. Heat mortality at this scale does not fall evenly across health systems. It concentrates where outdoor labor is common, where cooling depends on costly and unreliable power, and where food systems leave little margin for the body to cope. That helps explain why the list is led by the Sahel, South and Southeast Asia, and parts of Latin America, and why national totals differ from per-person risk.

Looking at what this means for diplomacy and response, the timeline compresses decisions. A six-month window through February, with effects extending into mid-2027, leaves humanitarian agencies, energy planners and agricultural ministries working on overlapping cycles. Excess heat raises immediate demand for cooling, water and clinical care. It also tests harvests and labor productivity in the same season. For governments and multilateral institutions, the question is less whether seasonal forecasts warrant attention than how to sequence early action across health, food and power without waiting for peak-season casualties to confirm the models.