This year’s powerful El Niño could result in 451,000 additional heat-related deaths worldwide between June 2026 and February 2027 compared with a normal year, according to new projections from the University of Chicago’s Climate Impact Lab.

The report estimates that global land temperatures will be around 1.2°C above normal in the coming months, resulting in 44% more extremely hot days than would typically be expected.

Researchers project around 239,000 additional heat-related deaths worldwide between September 2026 and February 2027.

The heaviest toll is expected in the Global South. The Sahel region, including Niger, Chad, Nigeria and Sudan, is projected to record around 66,800 additional deaths over the next six months. Nigeria alone could see about 31,400 additional deaths, while Indonesia could record around 19,300.

The Philippines, Vietnam, Thailand and Cambodia are projected to record around 19,400 additional heat-related deaths combined.

Researchers described the unusually high temperatures associated with this year’s El Niño as a “postcard from the future”, reflecting conditions that could become commonplace within the next two decades as the climate warms.

The report said targeted emergency measures in the most vulnerable areas could prevent tens of thousands of deaths in the coming months.

Michael Greenstone, co-founder of the Climate Impact Lab and an economist at the University of Chicago, said the projections could help decision-makers identify where immediate action could save the greatest number of lives.