Super El Niño could cause 451,000 extra heat deaths by February 2027

A new analysis from the Climate Impact Lab at the University of Chicago projects that the ongoing Super El Niño could drive approximately 451,000 additional heat-related deaths globally between June 2026 and February 2027. The estimate combines the natural warming pattern with the 1.2°C rise already caused by fossil-fuel pollution.

Researchers say the toll will likely climb because El Niño is expected to persist into the Northern Hemisphere spring, extending dangerous heat into summer months. The figure excludes deaths from El Niño-fuelled wildfires, floods and droughts.

“It is a number so large it can feel overwhelming, but it is made up of mothers and fathers, grandparents and neighbours.”

The study, published Wednesday, uses a peer-reviewed methodology but has not itself undergone peer review. Lead author Michael Greenstone said the model now predicts temperature impacts on mortality with the same rigour once reserved for crops.

Romania's Libertatea reports the highest risk period as September 2026 to February 2027, citing 239,000 excess deaths in that six-month window alone, with a margin of error of about 11,000. Both outlets note the event offers a preview of temperatures that may become normal within two decades.