El Nino 2026-27 Could Cause Hundreds of Thousands of Heat-Related Deaths, Study Warns

The powerful El Nino now developing in the Pacific could cause hundreds of thousands of heat-related deaths worldwide, with developing countries projected to bear the heaviest toll, according to a new study.

El Nino is a natural warming of the tropical Pacific that can disrupt weather around the world, bringing extreme heat and drought to some regions and heavy rainfall and flooding to others. The current event could become the strongest on record.

The Climate Impact Lab, a research group involving the University of Chicago and other institutions, said in a report released this week that extreme heat linked to the 2026-27 El Nino could cause 451,000 additional deaths worldwide.

The impact is projected to be concentrated overwhelmingly in the Global South. Over the next six months, researchers forecast 66,800 additional heat deaths across Africa’s Sahel region, including 31,400 in Nigeria and 17,500 in Sudan. Indonesia could see another 19,300 deaths, India 15,800, and Brazil 13,300.

The US could record around 3,500 additional heat deaths between September and February.

Michael Greenstone, a co-founder of the Climate Impact Lab and University of Chicago professor, said the scale of the projected losses could be difficult to grasp, stressing that the figures represented “parents and children, grandparents and neighbors.”

The warning comes after August became the hottest month on record globally, with temperatures averaging 16.96° Celsius (62.53° F). Western Europe also experienced its hottest summer on record, according to the EU’s Copernicus Climate Change Service.

The researchers said temperatures associated with the current El Nino offer a glimpse of conditions that could become far more common within the next two decades as the planet continues to warm.