Super El Niño Could Cause 451,000 Heat Deaths by 2027

A super El Niño building in the tropical Pacific could cause nearly half a million excess heat deaths around the world in the six months through February 2027, according to researchers at the University of Chicago's Climate Impact Lab. The lab released its projection on Wednesday, warning that the number of extremely hot days during this super El Niño is likely to rise 44 percent compared with normal years.

Heat is already one of the deadliest weather hazards on the planet. When the super El Niño pushes temperatures higher for weeks at a time, the people with the least protection feel it first: outdoor workers, older adults, and families in neighborhoods where air conditioning is rare and clinics are far away.

Where the deaths are expected

Nigeria is likely to suffer the most excess heat-related deaths from the super El Niño, with 31,400 projected between September 2026 and February 2027. Indonesia follows with 19,300 and Sudan with 17,600, the report says. Across the Sahel region of Africa, which includes Niger, Chad, Nigeria and Sudan, extreme heat is expected to cause an additional 66,800 deaths over the six-month period.

Southeast Asia is also expected to take a heavy toll. The Philippines, Vietnam, Thailand and Cambodia are projected to see 19,400 additional deaths combined. The researchers added that the count could climb higher if the super El Niño extends further into 2027. In that case, countries in the northern hemisphere, including India and Pakistan, would be especially vulnerable during their summer months.

A record-breaking climate event

A super El Niño develops when surface water in the tropical Pacific warms far above average, shifting weather patterns around the globe. This one is already breaking records months before its expected peak. Recent data showed sea surface temperatures in the tropical Pacific reaching 3.07 degrees Celsius above the long-term average, tying the mark set by the 2015-16 El Niño, as the New York Post reported. Scientists expect it to get hotter still, and the event arrives on top of a warming trend that has already produced record heat worldwide this decade, as GenZ NewZ reported last month.

A postcard from the future

The Climate Impact Lab described this year's super El Niño as a "postcard from the future," delivering temperatures that will become normal within a few decades. The report argues that emergency response efforts should be directed to high-priority regions now to bring down heat-related deaths in the coming months.

Michael Greenstone, an economist at the University of Chicago and a co-founder of the lab, said the report gives decision makers a clear view of where emergency action can be taken now to save tens of thousands of lives. The geography of the projection is not random. The Sahel combines long hot seasons with limited access to electricity and cooling, so when a heat wave hits, people who work outdoors have few ways to escape the temperature and clinics can fill fast with cases of heatstroke and dehydration. South and Southeast Asia face a different version of the same problem: dense cities where concrete traps heat overnight, leaving residents no cool hours to recover.

What governments are doing already

California moved this week to get ahead of the other side of the super El Niño: winter storms. On Sept. 21, Governor Gavin Newsom declared a statewide emergency so agencies could line up supplies, clear storm drains and prepare shelters before the rain starts. Forecasters say there is a strong chance this El Niño is stronger than any on record since 1950, which would mean heavier rain and snow, stronger winds, flooding and landslides for the state, USA Today reported.

The Climate Impact Lab's message is that heat deserves the same kind of advance planning. Its report names the regions where action now would save the most lives, and asks that emergency resources go there first. The full analysis was published by Reuters on Wednesday. For now, the researchers say, the priority is simple: get cooling, water and medical help to the places the report flags before the super El Niño's hottest months arrive.