A new report from the University of Chicago’s Climate Impact Lab projects that the ongoing El Niño weather pattern will contribute to 451,000 additional heat-related deaths worldwide between June 2023 and February 2024, compared to a typical year. The study, published on September 23, warns that developing nations will bear the brunt of the impact, with Sahel Africa, South and Southeast Asia, India, and Brazil facing the highest tolls.
The research estimates that 66,800 additional deaths will occur in the Sahel region, including Nigeria alone, while 19,400 deaths are projected across the Philippines, Vietnam, Thailand, and Cambodia. Indonesia is expected to see 19,300 additional fatalities, India 15,800, and Brazil 13,300. The study attributes the rise in mortality to El Niño-driven global land temperatures being 1.2°C above normal, resulting in 44% more extremely hot days than in a regular year.
El Niño’s Role and Global Impact
The Climate Prediction Center of the National Oceanic and Atmospheric Administration (NOAA) has stated that El Niño is strengthening, with a greater than 90% chance of a very strong event during the Northern Hemisphere fall and winter. The World Meteorological Organization (WMO) has cautioned that the phenomenon could disrupt rainfall and temperature patterns, increasing risks of floods, droughts, and extreme heat globally.
Researchers emphasize that the heat-related deaths are not solely tied to short-term heatwaves but also to sustained elevated temperatures over months. Emily Grover-Kopec, a co-author of the report, noted that the consistent exposure to higher average temperatures cumulatively affects human health, often in ways that are less visible than acute heatwaves.
Regional Breakdown of Projected Deaths
The study provides a detailed regional analysis of the projected fatalities:
- Sahel Africa (Nigeria, Sudan, Niger, Chad): 66,800 additional deaths
- Southeast Asia (Philippines, Vietnam, Thailand, Cambodia): 19,400 additional deaths
- Indonesia: 19,300 additional deaths
- India: 15,800 additional deaths
- Brazil: 13,300 additional deaths
The report highlights that poorer countries—already grappling with food insecurity, high energy costs, and climate change impacts—will face the most severe consequences. Michael Greenstone, a co-founder of the Climate Impact Lab and co-author of the study, explained that heat is particularly dangerous in regions that are already hot and economically vulnerable, as these areas often lack access to air conditioning, reliable water supplies, and robust healthcare systems.
Long-Term Implications and Adaptation Needs
The researchers describe the current El Niño as a “postcard from the future”, suggesting that the unusually warm conditions could mirror the average temperatures expected in coming decades due to climate change. The report underscores the urgency of adaptation investments to mitigate future risks, noting that without such measures, the mortality projections could become a recurring reality.
Greenstone added that the heat danger may persist beyond February, even as El Niño is expected to weaken by then. The long-term effects of the phenomenon could extend into next summer, particularly in regions already struggling with extreme heat.
Methodology and Data Sources
The projections are based on seasonal temperature forecasts combined with localized estimates of temperature-mortality relationships across more than 24,000 regions worldwide. The researchers compared expected deaths under El Niño-driven high temperatures with those projected under average temperatures from the last three decades to isolate the additional fatalities attributable to the weather pattern.
The study’s findings align with broader warnings from climate scientists about the intensifying impacts of El Niño amid a backdrop of record global temperatures and accelerating climate change. The report serves as a stark reminder of the human cost of extreme weather events, particularly in vulnerable regions.
Expert and Institutional Responses
While the report does not include direct responses from governments or international bodies, it reflects the consensus among climate scientists and researchers about the severity of El Niño’s impacts. The WMO and NOAA have both issued warnings about the potential for disruptive weather patterns, though neither has yet commented specifically on the mortality projections.
The study’s authors have called for immediate action to strengthen public health infrastructure, early warning systems, and climate adaptation strategies in high-risk regions. They emphasize that the current El Niño event provides a critical opportunity to prepare for future climate scenarios, where such extreme heat could become the norm rather than the exception.