What is El Niño? Key facts about how this climate pattern affects Nigeria

El Niño is a natural climate pattern characterised by unusually warm sea surface temperatures in the central and eastern tropical Pacific Ocean. It is the warm phase of the El Niño-Southern Oscillation (ENSO) cycle, which also includes La Niña (the cool phase) and neutral conditions.

El Niño can influence weather patterns worldwide, affecting rainfall, temperatures, agriculture, water supplies, and public health. However, its effects vary by region and from one event to another.

Tribune Online reports that Nigeria could record an additional 31,400 heat-related deaths between September 2026 and February 2027 as an unusually strong El Niño weather pattern intensifies, according to a report by the Climate Impact Lab.

How El Niño Works

Under normal conditions, trade winds blow from east to west across the tropical Pacific, pushing warm surface water towards Asia and Australia. This allows cooler, nutrient-rich water to rise from deeper ocean layers along the coast of South America.

During an El Niño event, the trade winds weaken or sometimes reverse. Warm water moves eastwards towards the Americas, reducing the upwelling of cold water and raising sea surface temperatures in the central and eastern Pacific. These changes can influence atmospheric circulation and shift rainfall and temperature patterns in other parts of the world.

10 Key Facts About How El Niño Could Affect Nigeria

1. Possible Changes in Rainfall in Northern Nigeria

El Niño can influence West African rainfall patterns, although its effects on Nigeria are not uniform or guaranteed. Depending on the event and other climate factors, some areas may experience reduced rainfall, longer dry spells or changes in the timing of the rainy season.

States such as Borno, Yobe, Sokoto, Kebbi and Kano are vulnerable to rainfall variability because of their dependence on seasonal precipitation.

2. Disruption of Rain-Fed Agriculture

Many Nigerian farmers depend on rainfall to grow crops. Unpredictable rainfall, prolonged dry spells and delayed rainy seasons can affect planting schedules and crop development.

Crops such as maize, sorghum and millet may suffer when water becomes unavailable during critical growth stages. Severe moisture shortages can reduce yields and, in some cases, result in crop failure.

3. Food Insecurity and Rising Food Prices

Poor harvests can reduce food supplies and increase prices, particularly when several farming areas are affected at the same time.

Northern Nigeria and parts of the Middle Belt are important agricultural production areas. When drought or irregular rainfall reduces output, households may face higher food costs and reduced access to nutritious meals. However, food prices are also influenced by insecurity, transport costs, exchange rates, storage and other economic factors.

4. Extreme Heat and Heat-Related Illnesses

El Niño is associated with higher global average temperatures, but its effects on temperatures in Nigeria depend on regional weather conditions and other climate influences.

Periods of extreme heat can increase the risk of dehydration, heat exhaustion and heatstroke. Outdoor workers, including farmers, construction workers and traders, may be particularly exposed when temperatures remain high for extended periods.

5. Water Scarcity and Falling Reservoir Levels

Below-average rainfall can reduce the replenishment of rivers, reservoirs and groundwater supplies. Communities that rely on streams, shallow wells and seasonal water sources may experience shortages during prolonged dry periods.

Reduced water availability can also affect irrigation, household activities and livestock. The severity of these impacts depends on local rainfall, existing water infrastructure and how water resources are managed.

6. Pressure on Livestock and Pastoral Livelihoods

Drought can reduce pasture growth and limit access to drinking water for cattle and other livestock. This may force pastoralists to travel farther in search of grazing land and water.

Where resources are scarce, competition between farmers and herders can intensify. However, such conflicts have multiple causes, including land-use changes, insecurity, population pressures and weak conflict-resolution mechanisms; they should not be attributed to El Niño alone.

7. Potential Effects on Hydropower Generation

Nigeria’s hydroelectric facilities, including Kainji, Jebba and Shiroro, depend on water availability in their respective river systems.

If prolonged dry conditions reduce inflows and reservoir levels, hydropower generation may be affected. The actual impact depends on rainfall across the relevant catchments, reservoir management, dam operations and other factors in the electricity system.

El Niño does not automatically cause reduced dam levels or nationwide power outages in Nigeria.

8. Changes in Flood Risk

El Niño does not mean that every affected area will experience drought. Climate patterns can produce different rainfall outcomes in different locations, and heavy rainfall may occur even after a dry period.

When intense rain falls on saturated, compacted or poorly drained ground, it can cause flash floods, erosion and damage to farmland and infrastructure. Urban drainage problems and settlement in flood-prone areas can make the consequences worse.

Nigeria’s flood risk also depends on local weather systems, river levels, land use and drainage conditions.

9. Increased Public Health Risks

Climate variability can affect public health through several pathways.

• Heat and dehydration: Extreme temperatures can cause heat-related illness, particularly among older people, children, outdoor workers and people without adequate cooling.
• Water-related diseases: Water shortages may force households to use unsafe sources, increasing the risk of diseases such as cholera and typhoid.
• Malaria and other vector-borne diseases: Changes in rainfall and temperature can affect mosquito breeding and disease transmission, although the direction and scale of the effect vary by location.
• Respiratory problems: Dry, dusty conditions can worsen symptoms for people with asthma and other respiratory illnesses.

These risks depend on local environmental conditions, access to healthcare, water and sanitation services, and public health preparedness.

10. Economic Pressure and Climate-Related Migration

When drought or irregular rainfall damages crops, reduces livestock productivity and weakens rural incomes, some households may move temporarily or permanently in search of work, food or more reliable living conditions.

Migration towards urban centres such as Lagos, Port Harcourt and Abuja can increase demand for housing, water, transport and other public services. However, migration decisions are complex and may also reflect insecurity, employment opportunities, education and other social or economic pressures.