A projection from the University of Chicago’s Climate Impact Lab estimates that the 2026–27 Super El Niño could contribute to approximately 451,000 additional heat-related deaths worldwide between June 2026 and February 2027. Brazil is expected to be the most affected country in Latin America, with a projected 13,300 additional deaths linked to extreme heat.
The estimate is a modeled risk scenario, not a confirmed death toll. The analysis combines seasonal temperature forecasts with mortality research covering 24,378 regions around the world. According to the University of Chicago Climate Impact Lab, global land temperatures could remain about 1.2°C above normal, while the number of extremely hot days could increase by roughly 44% compared with historical conditions.
Brazil faces a significant regional heat risk
Brazil’s projected position at the center of Latin America’s heat-mortality risk reflects the country’s large population, geographic scale and exposure to extreme weather. Heat impacts can be intensified by drought, wildfires and changes in rainfall, creating overlapping pressures for communities and health services.
According to Agência Brasil, the North and Northeast could account for much of the projected national impact. The estimate highlights the uneven distribution of climate risks across Brazil, where access to cooling, healthcare and reliable infrastructure varies between regions and communities.
Older adults and people living with cardiovascular or respiratory conditions are particularly vulnerable to dangerous heat. Outdoor workers may also face greater exposure because of prolonged physical activity in high temperatures. The effects can be more severe in places where households lack air conditioning, safe drinking water or other forms of protection from extreme weather.
Health authorities prepare for prolonged impacts
Brazil’s Ministry of Health says the El Niño event is currently strong and could become very strong, with conditions potentially continuing through March 2027. The ministry has expanded climate-health monitoring through its Climate and Health Information Centers and regional units of the National Public Health Emergency Force.
In a statement on the response to extreme heat in the Southeast, the Brazilian Ministry of Health described measures focused on strengthening surveillance and preparedness within the Unified Health System, known as SUS. These efforts are intended to help identify climate-related threats and support local responses as heat conditions develop.
The projected heat deaths should not be combined with other public-health forecasts. They represent a separate estimate from the possible increase in infectious diseases associated with El Niño-related weather patterns. Keeping the projections distinct is important because they measure different risks and rely on different analytical methods.
El Niño could also affect dengue transmission
A technical note from Brazil’s Ministry of Health warned that climate conditions associated with El Niño could increase the risk of arboviruses, including dengue and chikungunya, during 2026 and 2027. The document cites projections from Fiocruz’s InfoDengue system that Brazil could record approximately 1.7 million dengue cases in 2027.
That figure is a projection for dengue cases, not a forecast of heat-related deaths. It illustrates how a single climate event can create multiple and interconnected challenges for public health, including heat stress, infectious disease surveillance and pressure on emergency care systems.
Wider effects across the Americas
The potential impact is not limited to Brazil. A September situation report from the Pan American Health Organization said El Niño-related conditions were already affecting parts of the Americas.
The report cited prolonged coastal El Niño conditions in Peru, where heavy rains and flooding had been associated with reported deaths and damage to health facilities. The developments show how the same climate pattern can produce different hazards across Latin America, from dangerous heat and drought in some areas to flooding and infrastructure damage in others.
For Brazil, the Climate Impact Lab projection underscores the importance of treating extreme heat as a public-health emergency risk rather than only a weather event. The estimate remains uncertain because it depends on climate conditions, population exposure and the effectiveness of local measures. Still, the scale of the potential impact places heat preparedness, disease monitoring and protection for vulnerable groups at the center of the country’s response to the 2026–27 Super El Niño.
