A new research report from the University of Chicago-based Climate Impact Lab warns that the strong El Niño event occurring this year, along with associated record global heat, droughts, wildfires, and diminished water supplies, could result in nearly 451,000 additional heat-related deaths worldwide between June 2026 and February 2027. This projected increase in fatalities is notable when compared with typical heat-related mortality rates during non-El Niño years.

The study highlights that the greatest impact is expected to fall on poorer nations already facing challenges such as food insecurity and rising energy costs. These difficulties are compounded by broader climate change effects and geopolitical tensions, including the ongoing conflict in Iran. Michael Greenstone, a co-founder of the Climate Impact Lab and co-author of the report, emphasized that the risks linked to the current El Niño event may extend beyond its expected conclusion in February 2027, potentially affecting populations well into the following summer.

According to Greenstone, regions that are already hot and economically disadvantaged will face the most acute dangers from rising temperatures. He noted that "if you’re already in a hot place, the extra couple of degrees are going to be much more dangerous." In contrast, wealthier areas generally have better access to coping mechanisms such as air conditioning, stable water supplies, and effective healthcare systems, which can mitigate the health risks posed by extreme heat.

The study’s methodology involved combining seasonal temperature forecasts with localized mortality data from over 24,000 regions worldwide. Researchers calculated the additional heat-related deaths by comparing expected mortality under El Niño-driven temperature increases with the baseline mortalities projected if temperatures had remained consistent with averages from the past 30 years.

One finding of particular concern is the disproportionate impact on the Global South, a term referring broadly to developing countries rather than a specific geographic area. Within this group, the Sahel region of Africa—comprising countries along the southern edge of the Sahara Desert—was identified as the area likely to experience the highest mortality rates due to excessive heat.

The report underscores the pressing health risks posed by intensifying climate phenomena and highlights the need for targeted adaptation and mitigation efforts, especially in vulnerable regions with limited resources to manage extreme weather events.