Super El Niño could cause 451,000 heat deaths
More than 451,000 additional heat-related deaths could occur worldwide between September 2026 and February 2027 as an exceptionally strong El Niño pushes temperatures higher, according to estimates by researchers at the Climate Impact Lab.
The projected deaths would come on top of heat-related mortality already linked to rising global temperatures, while further casualties could result from droughts, wildfires and flooding associated with El Niño.
Researchers said the largest impacts are expected in tropical countries, with Nigeria, Indonesia, Sudan, India and Brazil among those projected to record the highest number of additional heat deaths.
The United States is also among the 20 most affected countries, with about 3,500 additional deaths projected over the six-month period.
The estimates cover the period through February 2027, when current temperature forecasts end, although researchers expect unusually high heat-related mortality to persist until June or July next year.
Heat risks spread across regions
The study assessed the relationship between temperature and excess mortality across 24,378 regions worldwide, combining historical temperature-death patterns with forecasts of additional warming caused by El Niño.
Researchers used average monthly heat mortality between 1996 and 2025 as the baseline.
The analysis suggests the Sahel region of Africa and Southeast Asia could face particularly severe impacts.
Climate Impact Lab co-founder Prof Michael Greenstone said the projections could help governments identify areas where early interventions may prevent deaths.
Measures could include improved heat-warning systems, cooling centres, additional staffing at health facilities during extreme heat and stronger protections for outdoor workers.
El Niño adds to already warmer climate
The current El Niño has already reached unusually high temperatures months before its expected peak.
Scientists have warned that the event is occurring against a warmer global climate, amplifying its potential health and economic consequences.
Researchers described the event as an indication of the type of temperatures that could become more common in the coming decades as global warming continues.
Dr Tamma Carleton of the University of California, Berkeley, said emergency measures could reduce deaths in the short term, but longer-term adaptation would be needed as extreme temperatures become more frequent.
Food security also under threat
The risks extend beyond direct heat exposure.
The World Food Programme warned in August that El Niño-related disruption could push around 50 million people into acute hunger, while crop losses could drive food prices higher.
Strong El Niño events can disrupt rainfall patterns, triggering drought in some regions and flooding in others, with consequences for agriculture, water supplies and electricity generation.
Scientists also warned that continued fossil-fuel emissions are raising the baseline temperatures on which natural climate events such as El Niño occur, increasing the severity of their impacts.
The new mortality estimate has not yet been published in a peer-reviewed journal, although the researchers said the methodology used in the analysis is based on peer-reviewed work.
