Scientists project that the exceptionally strong El Nino weather pattern currently developing could result in roughly 451,000 excess deaths globally due to extreme heat between June 2026 and February 2027. Tamma Carleton, director of research at the University of Chicago’s Climate Impact Lab, described the phenomenon as a “postcard from the future,” noting that projected land temperatures are expected to run approximately 1.2 degrees Celsius above normal.
This level of warming mirrors what climate models predict for the average person roughly two decades from now, but the current event delivers that intensity all at once. The estimate, derived from seasonal forecasts and historical mortality data, focuses specifically on direct health impacts from high temperatures and does not account for fatalities resulting from indirect consequences such as droughts, floods, or disease outbreaks.
El Nino, a term coined by Peruvian fishermen meaning “the little boy” or Christ Child due to its appearance around Christmas, involves the weakening of trade winds across the Pacific Ocean. This allows warm surface water to remain near the Americas rather than being pushed toward Asia, disrupting atmospheric circulation and altering weather patterns worldwide. The warming water fuels rainfall in the central and eastern Pacific, sending atmospheric waves that can affect regions across the tropics within a week and higher latitudes within two weeks.
The current episode, which began in June, is accelerating rapidly and is on track to become a “super” El Nino, potentially one of the strongest on record. While the event is expected to persist into the Northern Hemisphere’s spring, the lab’s current figures cover only the first nine months, with Carleton warning that the final death toll could be “meaningfully higher.”
The human cost is expected to fall disproportionately on lower-income nations that are already hot and have limited capacity to adapt. The Climate Impact Lab anticipates significant increases in mortality in the Sahel region, South and Southeast Asia, and parts of Latin America. Nations projected to suffer the highest number of fatalities include Nigeria, Sudan, Niger, Chad, India, Indonesia, and Brazil, with many deaths expected between December and February.
Extreme heat places severe strain on the cardiovascular and respiratory systems, aggravating underlying conditions that are often recorded as the cause of death rather than the heat itself. Carleton noted that most heat-related fatalities do not appear in official statistics as such. However, because the study relies on annual mortality rates rather than daily data, it largely filters out “mortality displacement”—deaths that are merely brought forward by days or weeks. Ben Armstrong, an emeritus professor at the London School of Hygiene and Tropical Medicine, stated that if the figure is accurate, most individuals counted would have lived at least six months longer.
Unlike retrospective studies, this forecast aims to provide actionable data before the deaths occur. Researchers suggest that targeted interventions, including heat warnings, cooling centers, hydration stations, protections for outdoor workers, and increased healthcare capacity, could prevent tens of thousands of deaths. Carleton emphasized that the event serves as a warning to invest now in adaptive capacity for the warmer climate that will likely become normal by the 2040s.
I keep thinking about the vulnerable communities in Nigeria and India who have the least resources to adapt to this.
Wait, is this estimate only covering nine months? The final death toll might be much worse than reported.
That 1.2-degree jump hitting us now instead of in twenty years is genuinely terrifying. It really feels like a preview of our future.