This year’s powerful El Nino weather pattern could lead to an estimated 451,000 additional heat-related deaths worldwide through February 2027, according to a new projection from the Climate Impact Lab at the University of Chicago.
Researchers say the ongoing El Nino could become one of the strongest on record, bringing unusually high temperatures and increasing the number of extremely hot days across several parts of the world. The projected deaths are additional fatalities compared with what would normally be expected under average temperature conditions.
The Climate Impact Lab estimates that global land temperatures could remain around 1.2°C above normal during the coming months, while the number of extremely hot days could rise by about 44 percent compared with a typical year.
The researchers examined temperature-related mortality across 24,378 regions and combined historical relationships between heat and deaths with temperature forecasts to estimate the potential impact of this year’s El Nino.
The projected health impact is expected to be particularly severe across countries in the Global South. The African Sahel is projected to experience about 66,800 additional heat-related deaths, with Nigeria accounting for approximately 31,400 of those deaths.
Sudan, Niger and Chad are also among the countries facing significant projected increases in heat-related mortality. Indonesia is estimated to record around 19,300 additional deaths, while the Philippines, Vietnam, Thailand and Cambodia could collectively experience approximately 19,400 additional deaths.
India is projected to face about 15,800 additional heat-related deaths, while Brazil could see approximately 13,300 more deaths linked to extreme heat during the period covered by the analysis.
El Nino is a naturally occurring climate pattern associated with unusually warm ocean surface temperatures in the central and eastern tropical Pacific. Although the phenomenon occurs naturally, its effects can interact with a warming climate and contribute to more extreme heat and changes in rainfall patterns.
The current event has raised particular concern because researchers expect it to produce significant temperature increases in different parts of the world. The World Meteorological Organization has also warned about the potentially historic strength of the current El Nino, while forecasts indicate that its strongest phase could come later in 2026.
Extreme heat can be particularly dangerous for older adults, children, people with existing vulnerabilities and outdoor workers. High temperatures can increase the risk of heat exhaustion, heatstroke and other serious health complications, especially when communities lack access to cooling facilities and adequate healthcare.
Researchers say the projections are intended not only to measure potential losses but also to identify areas where immediate preparation could save lives. Measures such as early heat warnings, cooling centers, hydration stations, stronger health-system capacity and protections for outdoor workers can help reduce exposure to dangerous temperatures.
The projected figure of 451,000 deaths is not a confirmed future death toll. It is an estimate based on climate and mortality models, and researchers say the projections will be updated as the El Nino event develops.
The Climate Impact Lab has described the current extreme heat as a warning of conditions that could become more common in the future as global temperatures continue to rise. Researchers argue that investment in heat preparedness and long-term climate adaptation could become increasingly important for protecting vulnerable populations.
For countries already facing high temperatures, limited cooling infrastructure and pressure on healthcare systems, the coming months could present additional challenges. The latest projections therefore put renewed focus on heat preparedness as governments and communities respond to the evolving El Nino event.