A powerful El Niño weather pattern developing in the Pacific could contribute to as many as 451,000 excess heat-related deaths worldwide over the six months to February 2027, according to a new estimate by researchers at the University of Chicago’s Climate Impact Lab.
The researchers said the developing “super El Niño” is expected to increase the number of extremely hot days globally by about 44 per cent compared with normal years, potentially exposing millions of people to dangerous levels of heat.
The estimate, reported by Reuters on Wednesday, September 23, is a projection of additional deaths associated with the expected increase in heat and should not be interpreted as a prediction that 451,000 people will necessarily die.
Nigeria projected to record highest number
Nigeria is projected to have the highest number of excess heat-related deaths among individual countries, with an estimated 31,400 additional fatalities between September 2026 and February 2027.
Indonesia follows with about 19,300 projected excess deaths, while Sudan is estimated at approximately 17,600.
Across the Sahel, including Nigeria, Niger, Chad and Sudan, researchers estimate that extreme heat could contribute to about 66,800 additional deaths during the six-month period.
The researchers warned that the number could rise if the El Niño event continues into 2027, particularly because parts of the Northern Hemisphere could experience additional heat during their summer months.
El Niño already affecting weather patterns
El Niño is a naturally occurring climate phenomenon associated with unusually warm sea-surface temperatures in the tropical Pacific Ocean. Changes in the Pacific can alter weather patterns across different parts of the world.
Nature reported earlier this month that the current El Niño is already contributing to weather disruptions, including drought conditions in parts of Central America and the western Pacific, reduced rainfall in India and increased wildfire risks in Indonesia. Other regions, including parts of South America and the Horn of Africa, face increased risks of heavy rainfall and flooding.
Scientists have also warned that the current event could become unusually strong.
A recent study reported by The Guardian found evidence that human-caused global warming may be contributing to stronger and more variable El Niño events, although scientists continue to study the precise relationship between long-term climate change and individual El Niño events.
Researchers call for early action
Michael Greenstone, an economist at the University of Chicago and co-founder of the Climate Impact Lab, said the estimates could help governments identify regions where preventive measures could save lives during the coming months.
The researchers recommended directing emergency preparedness and response measures towards areas expected to experience the greatest heat-related risks.
The projection comes as governments and humanitarian organisations prepare for a potentially disruptive El Niño season, with concerns extending beyond heat to drought, flooding, food security and pressure on water supplies.
The International Rescue Committee has separately warned that the developing super El Niño could threaten food security in parts of Central America, particularly Honduras, Guatemala and El Salvador.
The Climate Impact Lab’s 451,000 figure therefore represents a modelling estimate of potential excess deaths, rather than a confirmed number of fatalities. The actual impact will depend on the intensity and duration of the El Niño event, local weather conditions and the effectiveness of heat-response measures.
