Climate Impact Lab projects 66,800 additional heat-related deaths across the Sahel between September 2026 and February 2027, with Nigeria accounting for nearly half of the estimated total. Nigeria could experience an estimated 31,400 additional heat-related deaths between September 2026 and February 2027 as an unusually strong El Niño event drives temperatures above normal levels, according to new projections from the University of Chicago’s Climate Impact Lab.
The projection places Nigeria among the countries expected to experience the largest mortality impacts from the current El Niño event. Across the Sahel, researchers estimate that 66,800 additional heat-related deaths could occur during the six-month period compared with a normal year.
The Climate Impact Lab’s wider analysis projects approximately 451,000 additional heat-related deaths globally from June 2026 through February 2027, based on temperature forecasts and established relationships between heat exposure and mortality.
Nigeria projected to face the largest impact in the Sahel
The countries identified as facing the greatest projected mortality impacts in the Sahel are Nigeria, Sudan, Niger and Chad.
The Climate Impact Lab estimates:
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Nigeria: 31,400 additional heat-related deaths
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Sudan: 17,500
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Niger: 10,000
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Chad: 8,000
Together, the four countries account for the estimated 66,800 additional deaths projected across the Sahel between September and February.
Nigeria’s projected figure represents almost half of the regional total.
The researchers also estimate that Nigeria could experience 15,400 additional heat-related deaths between December and February, making the later part of the forecast period particularly important for preparations.
Why the Sahel is particularly vulnerable
The Sahel stretches across Africa between the Sahara Desert and the wetter tropical regions farther south. Its combination of high temperatures, limited resources and significant dependence on outdoor economic activity leaves many communities vulnerable to extreme heat.
The Climate Impact Lab says the regions expected to experience the greatest temperature anomalies during the forecast period are also among those with fewer resources available for adaptation.
That matters because extreme heat does not affect all populations equally. Access to electricity, cooling, healthcare and early-warning systems can influence whether high temperatures translate into serious illness and death.
The lab’s broader research has similarly found that poorer countries are projected to experience substantially higher heat mortality than wealthier countries under future warming scenarios.
How the researchers arrived at the projection
The researchers combined seasonal temperature forecasts from the European Centre for Medium-Range Weather Forecasts (ECMWF) with Climate Impact Lab research examining the relationship between temperature and mortality.
Their mortality models cover 24,378 regions worldwide, accounting for differences in local climates, population vulnerability and the ability of communities to adapt to heat.
The projected deaths represent the estimated difference between mortality during the forecast period and what researchers would expect during the corresponding months of a normal year, using 1996–2025 as the baseline period.
The figures are therefore projections rather than confirmed deaths. The researchers also incorporate uncertainty arising from both the seasonal weather forecasts and the estimated relationship between temperature and mortality.
Who could face the greatest danger?
The study itself did not specifically model which demographic groups within each country face the greatest risk.
However, the researchers point to existing evidence showing that older adults, young children and people with chronic health conditions can face greater risks during periods of extreme heat.
Outdoor workers are also particularly exposed because they may spend many hours in direct heat with limited opportunities to cool down.
For countries such as Nigeria, where many livelihoods depend on outdoor work, extreme heat can therefore become both a public-health and economic concern.
Electricity access is a critical part of heat protection
One of the challenges highlighted by the Climate Impact Lab’s broader research is the relationship between heat exposure and access to electricity.
Cooling systems such as fans and air conditioners can reduce exposure to dangerous temperatures, but reliable electricity is necessary to operate them.
This creates a particular challenge for lower-income communities, where households may have limited access to reliable power or may be unable to afford sustained cooling during prolonged periods of extreme heat.
The Climate Impact Lab has previously warned that countries expected to face some of the greatest increases in heat-related mortality are often also those with fewer resources to expand electricity consumption for cooling.
What governments can do now
The Climate Impact Lab says the projections can help governments and humanitarian organisations identify where preventive measures could have the greatest effect.
Among the interventions highlighted by the researchers are:
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Heat-warning and early-warning systems
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Cooling centres and hydration stations
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Health outreach to vulnerable people
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Protections for outdoor workers
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Expanded healthcare capacity during periods of extreme heat
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Improved temperature forecasting
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Greater access to cooling technologies
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Advance funding for emergency responses
These measures are intended to reduce exposure and allow health authorities to act before extreme heat produces its most severe consequences.
A warning about a hotter future
The researchers describe the current El Niño-driven temperatures as a possible glimpse of conditions that climate change could make more common in coming decades.
The Climate Impact Lab estimates that the current event is producing temperatures comparable to levels that climate models project could become more typical roughly 20 years from now.
The organisation says the immediate mortality projections therefore serve two purposes: identifying where emergency interventions may save lives during the current El Niño and highlighting the need for longer-term investment in climate adaptation.
For Nigeria and other countries across the Sahel, the projections put extreme heat alongside other climate-related risks that require preparation in advance rather than responses after impacts have already occurred.
The Climate Impact Lab says its estimates will be updated as the El Niño event develops and additional forecasts become available.
