Public health researchers are warning that the current El Niño climate pattern, already confirmed as one of the strongest on record, could be linked to roughly 450,000 additional deaths worldwide over the next six months. The projection, drawn from epidemiological modeling of past El Niño cycles, points to disease outbreaks, food shortages, and extreme weather in low-income tropical regions as the primary drivers rather than the climate phenomenon itself.
El Niño is a natural warming of surface waters in the central and eastern Pacific Ocean that shifts rainfall and temperature patterns across much of the globe. This cycle has been building for months, and as a recent study found it stronger than at any point in the past 1,000 years, scientists have grown increasingly concerned about its downstream humanitarian consequences.
How a Weather Pattern Turns Deadly
El Niño does not kill directly. Instead, researchers say it compounds existing vulnerabilities in regions with weak health infrastructure, sparse rainfall, and dependence on subsistence agriculture. The pattern typically brings drought to parts of southern Africa, Southeast Asia, and Central America, while triggering heavier rainfall and flooding in East Africa and parts of South America.
- Vector-borne disease: Warmer, wetter conditions in some regions expand mosquito habitats, fueling spikes in malaria and dengue fever.
- Waterborne illness: Flooding and contaminated water supplies raise the risk of cholera and other diarrheal diseases, particularly in areas lacking sanitation infrastructure.
- Food insecurity: Drought-damaged harvests in vulnerable farming regions can push malnutrition rates higher, especially among children under five.
- Extreme heat: Prolonged heat waves strain health systems and disproportionately affect the elderly and outdoor laborers.
Researchers modeling the current event say the compounding effect of these factors, layered on top of already-strained health systems in parts of sub-Saharan Africa, South Asia, and Central America, is what produces mortality estimates in the hundreds of thousands.
Historical Precedent
The projection is not without precedent. The severe 2015-2016 El Niño, then considered one of the strongest on record, was associated with documented surges in cholera cases in East Africa, dengue outbreaks across Latin America, and widespread crop failures that pushed millions into food insecurity. Public health researchers have since used that event as a baseline for modeling the potential toll of future occurrences.
“El Niño acts as a stress multiplier,” one climate-health researcher involved in similar modeling efforts has noted in prior published work. “It doesn’t create vulnerability out of nothing — it exposes and worsens vulnerabilities that already exist in fragile health and food systems.”
Given that this year’s event has already been described as reaching historic strength, researchers argue the associated humanitarian risks could exceed those seen in 2015-2016, particularly in countries still recovering from pandemic-era strain on health budgets.
Where the Risk Is Highest
Modeling points to several regions as facing the greatest exposure over the coming six months:
- Horn of Africa: A region already cycling between drought and flooding, with fragile food systems and limited healthcare access.
- Southeast Asia: Vulnerable to both drought-driven crop losses and dengue fever surges tied to shifting rainfall.
- Central America: At risk of reduced rainfall affecting staple crop yields, compounding existing food insecurity.
- Parts of South America: Facing potential flooding along the Pacific coast, raising risks of waterborne disease.
Health officials in several of these regions have already begun raising alarms about strained resources, though comprehensive on-the-ground data for the current cycle is still emerging.
Calls for Early Intervention
Public health experts say the projected toll is not inevitable and can be substantially reduced through early intervention. Forecast-based financing — where humanitarian funds are released ahead of a predicted crisis rather than after it unfolds — has shown promise in past El Niño cycles for reducing mortality tied to drought and disease outbreaks.
Recommended measures include pre-positioning emergency food supplies, expanding malaria prevention campaigns before peak transmission season, reinforcing water sanitation systems ahead of flooding, and strengthening disease surveillance to catch outbreaks early.
International health agencies have historically used El Niño forecasts to guide aid allocation, though funding for such preventive measures often falls short of what modeling suggests is needed. Researchers involved in the current projections say the 450,000-death estimate should be treated as a call to action rather than an unavoidable outcome, emphasizing that the scale of the eventual toll will depend heavily on how quickly governments and aid organizations respond in the coming months.
What Comes Next
Climate scientists expect the current El Niño to begin weakening in the coming months as ocean temperatures gradually normalize, though its downstream effects on rainfall, agriculture, and disease transmission are likely to persist well beyond the event’s peak. Health researchers say they will continue updating mortality projections as more regional data becomes available, with particular focus on food security assessments and disease surveillance reports expected later this year.
