The 2026 El Niño has broken Pacific temperature records and could contribute to approximately 857,000 heat-related deaths worldwide through March 2027, according to the University of Chicago's Climate Impact Lab. This is a model-based cumulative projection, not a recorded death toll; roughly 373,000 deaths are forecast during October–March.
The developing event surpassed the previous daily Niño 3.4 temperature-anomaly record: 3.11°C in September versus 3.08°C in 2015. September also registered a record 29.70°C sea-surface temperature in that region, while August tied the warmest month ever measured globally. NOAA estimates an 83% chance that the October–December event will exceed the strongest El Niño in its record dating to 1950.
The outlook intensifies earlier warnings about how vulnerable communities bear disproportionate climate risks. Researchers project especially severe heat mortality in Nigeria, India and Indonesia.
Scientists recommend targeted early-warning systems, accessible cooling centers, safer schedules for outdoor workers, and emergency funding focused on high-risk areas. Better forecasts can help authorities act before heat becomes deadly.
The historical records and mortality projections
Projected cumulative heat deaths
857,000
June 2026 – March 2027
Chance of record El Niño strength
83%
October – December 2026
| Indicator | Finding |
|---|---|
| Daily Niño 3.4 temperature anomaly | 3.11°C, exceeding 2015's 3.08°C |
| September Niño 3.4 sea temperature | Record 29.70°C |
| August 2026 global temperature | Joint hottest month on record |
| September 2026 global temperature | Second warmest September on record |
| Projected October–December anomaly | Approximately +3.7°C; not yet an observed seasonal record |
The University of Chicago's tracker forecasts approximately 56,000 heat-related deaths in Nigeria, 55,000 in India and 29,000 in Indonesia during its October–March outlook period.
N.B. These figures are projections, not confirmed fatalities