A new report by the Climate Impact Lab, released on Wednesday, 23 September, projects that this year's 'Super El Niño' — potentially the strongest on record — could lead to 451,000 deaths from extreme heat globally in the coming months, with India alone facing an estimated 15,800 additional fatalities. The findings go beyond the well-documented threats of drought, flooding, and wildfires, zeroing in on direct heat mortality as a central and under-addressed dimension of El Niño's toll.

Scale of the Projected Death Toll

The 451,000 deaths projected during just the first half of the El Niño cycle are approximately 65 times larger than the 6,800 people reported dead or missing from the recent flash floods in Nepal. According to the report, the casualties will be concentrated overwhelmingly in the Global South, where adaptive capacity is lowest and heat exposure is most severe.

In Africa's Sahel region, an estimated 66,800 additional deaths are projected over the next six months. Nigeria accounts for nearly half of that figure, with 31,400 projected deaths. Sudan faces 17,500 additional heat deaths, Niger faces 10,000, and Chad faces 8,000.

In Southeast Asia, the combined toll across the Philippines, Vietnam, Thailand, and Cambodia is projected at 19,400, while Indonesia faces 19,300. In South America, Brazil is the hardest-hit nation with 13,300 projected deaths.

India's Exposure and Risk

India is projected to record 15,800 additional heat-related deaths attributable to Super El Niño conditions — a figure that does not include the secondary impacts of associated droughts or floods. The country's large population, high outdoor workforce, and significant rural heat exposure make it especially vulnerable to extreme temperature events of this scale.

Notably, this El Niño is described in the report as a 'postcard from our future' — bringing temperatures that climate change models project will become the norm within approximately 20 years, even without an El Niño event. In that framing, the current emergency also doubles as a stress test of adaptation infrastructure.

What Experts Said

Michael Greenstone, co-founder of the Climate Impact Lab and the Milton Friedman Distinguished Service Professor in Economics at the University of Chicago, said: '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. 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 added that the report 'allows decision-makers to see exactly where emergency actions can be taken now to save tens of thousands of lives in the coming months.'

Report co-author Tamma Carleton, Faculty Head of Research for the Climate Impact Lab and an Assistant Professor at the University of California, Berkeley, cautioned against treating extreme heat as a permanent emergency: 'Increasing emergency response and better targeting our efforts can save many lives this year. But 20 years from now, once today's extreme temperatures become the new normal, we don't want to be in a constant state of emergency. We need to mobilize resources now to design, deploy, and evaluate the preparation and planning tools that will save lives in the years ahead.'

Adaptation Measures and Immediate Priorities

The Climate Impact Lab's Adaptation Inventory offers a regularly updated, peer-reviewed evidence base of interventions proven to reduce heat mortality. These include early warning systems, cooling centres, and protections for outdoor workers — measures that the report says are already being deployed in some regions but require much greater scale and targeting.

The Lab emphasises that mortality from extreme temperatures must be treated as central to El Niño preparedness, alongside existing food security efforts. Longer-term adaptation planning under consideration includes more accurate temperature forecasting and wider access to cooling technologies.

What Comes Next

The Climate Impact Lab's ongoing research aims to identify scalable interventions for the most vulnerable geographies. Governments and international agencies have been urged to direct emergency resources toward the high-priority regions identified in the report, where targeted action could, according to the researchers, avert tens of thousands of deaths over the coming months.