The Super El Niño could lead to an additional 66 800 heat-related deaths across Africa’s Sahel over the next six months, with nearly half of those deaths projected to occur in Nigeria.
For the first nine months of the current El Niño, from June 2026 to February 2027, researchers at the Climate Impact Lab at the University of Chicago project 451 000 additional heat-related deaths globally.
In a new report, they estimate that Nigeria could see 31 400 more heat-related deaths than in a normal year between September and February, followed by Sudan with 17 500, Niger and Democratic Republic of Congo with about 10 000 each and Chad with 7 900.
According to the lab’s interactive data, South Africa is among the 50 countries with the highest projected number of additional heat-related deaths between September this year and February next year, with about 1 200 additional deaths projected over the same period.
The researchers project 239 000 additional heat-related deaths globally between September and February, with an uncertainty range of about 11 000 either side of that estimate.
“With current forecasts suggesting El Niño will remain in place through spring 2027, we expect all of these numbers to grow even higher, particularly as impacts such as higher-than-average temperatures and heat-related deaths will linger into June and July,” the report said.
The heat deaths projected for the rest of this year would hit the Global South the hardest, the report warned. Regions projected to see the largest increase in heat-related deaths over the next six months are spread across the Global South.
In South-East Asia, the extra heat is projected to cause an additional 19 400 deaths in the Philippines, Vietnam, Thailand and Cambodia and 19 300 deaths in Indonesia. India is projected to see 15 800 more deaths and Brazil 13 300 deaths from El Niño’s heat.
The Climate Impact Lab said the deaths from extreme heat would come “on top of the impacts from droughts, wildfires and flooding expected from hotter temperatures and shifting rainfall patterns”, as the El Niño could become the strongest on record.
Global land temperatures were expected to be about 1.2°C above normal in the coming months, resulting in 44% more extremely hot days than would be expected in a normal year.
It said the unusually warm conditions would resemble temperatures that climate change was projected to deliver about 20 years from now.
“El Niño is effectively pushing us into the future — exposing us to temperatures that won’t be the norm for another two decades — before we have time to adapt and protect ourselves,” the researchers said.
The timing of the projected deaths will vary between countries. In Nigeria, for example, about 15 400 additional heat-related deaths are projected between December and February, while Indonesia is expected to see about 10 400 during the same period.
The projections are based on the relationship between temperature and excess mortality across 24 378 regions worldwide, taking differences in local climate, vulnerability and adaptive capacity into account.
The researchers applied the relationships to seasonal temperature forecasts to estimate changes in temperature-related excess mortality compared with the 1996–2025 average.
The analysis carries uncertainty from both the seasonal forecast and the estimates of the relationship between temperature and excess mortality. The figures are projections of excess deaths compared with a normal year, rather than a prediction of the exact number of people who will die.
The Climate Impact Lab said the projections were intended to identify where interventions could be targeted before deaths occur. Measures that could reduce the impacts of extreme heat include heat warnings, outreach to vulnerable people, cooling centres and hydration stations, protections for workers exposed to heat and increased health-system capacity.
“We have long been able to predict the impacts of temperatures on crops and now we can predict their impact on the worst outcome — death,” said Michael Greenstone, a co-founder of the Climate Impact Lab and the Milton Friedman Distinguished Service Professor in Economics at the University of Chicago, in a statement.
“The result is that we now can estimate that 451 000 people may die in the coming months due to El Niño. This is such a large number that it can be numbing, but it is made up of parents and children, grandparents and neighbours, people going to work, caring for families and living their lives.”
Greenstone said the report allowed decision-makers to see exactly where emergency actions could be taken to save tens of thousands of lives in the coming months.