A 451,000-Death Warning: El Niño Heat Threatens a Heavy Toll Across the Global South

A Climate Impact Lab report projects 451,000 additional deaths from extreme heat during the first nine months of this El Niño, with the burden concentrated in the Global South. Its country estimates could help direct urgent protections, while raising a longer-term question: how will vulnerable communities cope as extreme heat becomes more frequent?

El Niño's heat could cause 451,000 additional deaths between June and February, according to a new forecast by the Climate Impact Lab. The projected toll is concentrated overwhelmingly in the Global South, with particularly severe losses expected across the Sahel. The forecast gives governments a narrow opportunity to direct heat protection toward places where the greatest number of lives are at risk.

The estimate covers deaths associated with extreme hot days from June through February. It does not include potential harm from droughts, wildfires or floods. Nor is it a count of lives already lost: the Lab says it will revise its projections as El Niño progresses. For governments making decisions now, that distinction is crucial. A forecast can change, but waiting for a confirmed death toll would forfeit much of its value.

The places behind the global number

The report projects 66,800 additional heat deaths across the Sahel over the next six months. Nigeria accounts for 31,400 of that estimate, followed by Sudan with 17,500, Niger with 10,000 and Chad with 8,000. The scale of the projected losses makes the region an immediate priority for heat response.

The risk extends well beyond Africa. The Lab estimates 19,300 additional deaths in Indonesia and a combined 19,400 in the Philippines, Vietnam, Thailand and Cambodia. India faces a projected 15,800 additional deaths, while Brazil faces 13,300. These country figures show how widely the threat is distributed, even as the largest projected losses cluster in particular places.

National estimates, however, cannot by themselves tell officials which neighbourhoods or workers need help first. Decisions about warnings, cooling spaces and protection during outdoor work require a closer understanding of local exposure. The report identifies where the burden may be greatest; turning that warning into an effective response is a task for the institutions serving those populations.

Heat belongs at the centre of El Niño planning

El Niño preparation often involves threats to rainfall and food security. Those concerns remain, but the Lab's projections argue for treating lethal heat as a major risk in its own right. A response focused on crops, drought or flooding could leave people exposed to dangerous temperatures even where other preparations are underway.

The Climate Impact Lab points to early warning systems, cooling centres and protections for outdoor workers among measures supported by research in its Adaptation Inventory. Such measures give authorities options before the projected deaths occur. Their effect in this El Niño will depend on where they are deployed, whom they reach and whether people can use them when heat becomes dangerous.

This creates a difficult question for governments and response organisations: how quickly can a broad forecast guide specific action? The figures indicate where to concentrate attention, but they do not establish which protections are already in place or where coverage is weakest. Local reporting on those gaps would reveal whether the areas facing the highest projected toll are receiving a response equal to the risk.

An emergency that points beyond one season

The report also casts this El Niño as a glimpse of temperatures climate change could bring roughly 20 years from now. The comparison gives the forecast a second purpose. It is both a warning about the coming months and a test of whether heat protection can become a dependable part of public planning.

Emergency measures can reduce immediate danger, but a future of more persistent extreme heat would demand preparation that does not have to be rebuilt with every crisis. More accurate temperature forecasts and wider access to cooling technologies are among the longer-term approaches the Lab identifies. Its researchers also acknowledge the need to determine which approaches work and can be expanded in the most vulnerable places.

Report co-author Tamma Carleton frames the challenge in similar terms: stronger emergency response could save lives this year, while sustained investment is needed to avoid a recurring state of emergency. The question for policymakers is how to pursue both timelines at once. Resources directed toward the current El Niño may address urgent exposure; choices made after it passes will shape readiness for the heat that follows.

What the forecast will be judged against

The Climate Impact Lab plans to update its estimates as El Niño progresses. Those revisions will show whether the projected toll rises or falls and whether the greatest risks remain concentrated in the same places. Each update could help authorities reassess where protection is most urgent, provided the findings reach those making decisions in time.

It should be noted that projections carry uncertainty, while effective warnings, cooling access and protections for outdoor workers could reduce the losses the report anticipates. Hence, a lower recorded toll would need to be examined alongside the actions taken, rather than treated on its own as evidence that the danger was overstated.

The report identifies countries facing substantial projected losses and measures that could help, but the reach of those measures remains unclear. Tracking where protections are put in place, and whether they reach people most exposed to heat, would show whether a global warning has become an effective local response.