Could El Niño Cause 451,000 Heat Deaths? What the Projection Means

Verified Baseline

The 451,000 figure is a model estimate

The University of Chicago’s Climate Impact Lab projects 451,000 excess heat deaths globally from June 2026 through February 2027 compared with a normal year. The report estimates 44% more extremely hot days and says the burden will fall disproportionately on the Global South. Reuters reported the findings September 23.

This does not mean 451,000 deaths have occurred or are inevitable. It is an estimate produced by combining temperature forecasts with modeled relationships between heat and mortality.

How the Estimate Works

Researchers compare forecast heat with a normal-year baseline

The team estimates deaths expected under El Niño-driven temperatures and compares them with deaths expected if temperatures resembled the 1996–2025 average. For the next six months, it projects 239,000 additional deaths globally, with an uncertainty range of about ±11,000. The full nine-month figure includes the already-started June-to-February period.

The detailed methodology is expected to be published in a peer-reviewed journal but had not completed that process at publication time. That limits independent assessment of assumptions, country-level data quality and how adaptation is represented.

Where Risk Is Concentrated

The model identifies the Sahel and parts of Asia as major hotspots

For the next six months, the report projects about 66,800 excess heat deaths across the Sahel, including 31,400 in Nigeria, 17,500 in Sudan, 10,000 in Niger and 8,000 in Chad. It also projects 19,300 in Indonesia, 19,400 across the Philippines, Vietnam, Thailand and Cambodia, and 15,800 in India.

Those figures are forecasts, not country death certificates. They are most useful for identifying where preparedness could have the largest payoff.

Why It Matters

Heat protection can change the outcome

Early warnings, public cooling spaces, worker protections, reliable electricity, hydration access and targeted outreach to older adults and people with chronic illness can reduce heat deaths. Health systems can also plan staffing and supplies around forecast heat periods.

The projection should inform preparedness without manufacturing certainty. Actual mortality will depend on weather, exposure, local infrastructure, public-health response and whether people can access cooling and care.

Practical Implications

Use local warnings, not a global number, for personal decisions

People should follow their national weather service and local health authority for heat alerts. During extreme heat, check on vulnerable neighbors, reduce strenuous activity during the hottest hours and seek urgent care for confusion, fainting or other signs of heat stroke. This is general public-health information, not personalized medical advice.

What Remains Uncertain

The final strength, local weather and mortality response can differ

“Super El Niño” is an informal label; NOAA generally uses “very strong” for the highest category. El Niño changes global odds but does not determine the weather of every place or day. Mortality models also cannot perfectly capture migration, outages, conflict, air conditioning access or emergency interventions.