El Niño heat projected to cause 451,000 excess deaths globally by early 2027
A Climate Impact Lab assessment estimates that heat associated with El Niño could contribute to 451,000 additional deaths worldwide from June 2026 through February 2027. The projection includes 239,000 deaths during September 2026-February 2027, with the Sahel, Indonesia, and India among the most affected. The report comes as NOAA records central Pacific sea-surface temperatures reaching levels last seen during the 2015-16 El Niño.
The projection relies on a 1996–2025 mortality baseline, with the June–August portion representing modeled figures rather than confirmed counts. Regional estimates for the September–February window place the Sahel as the hardest hit, with Nigeria alone accounting for roughly 31,400 of that region's 66,800 projected deaths. Indonesia, India, and Brazil also show substantial projected impacts.
NOAA's weekly Niño-3.4 reading of +3.0°C matched the November 2015 peak, while a daily anomaly of +3.05°C set a new record. However, NOAA's official strength metric, the RONI, uses a three-month average, so a daily record does not guarantee a record event. Forecasts indicate a 75% chance the RONI exceeds +2.5°C, which would surpass all events since 1950.
The projected toll could place severe strain on public health systems in tropical and subtropical nations, particularly where heat adaptation is limited. Vulnerable groups—including outdoor laborers, the elderly, and those without reliable cooling—may face the highest risk. These estimates could prompt governments and aid agencies to pre-position resources and refine early-warning systems. The figures may also sharpen public debate on climate resilience, as they quantify a direct human cost from a natural climate cycle amplified by warming.