Record-Low SOI Signals 'Very Strong' El Niño, Threatening African Economies

Why Forecasters Are Sounding the Alarm on a 2026-2027 Super El Niño

The Australian Bureau of Meteorology has issued a stark warning: the El Niño forming in the tropical Pacific is on course to be one of the strongest on record. Its main yardstick, the Southern Oscillation Index (SOI), plummeted to -29.1 in July – a reading not seen in over forty years and far below the -7 threshold that typically marks an El Niño event. The Bureau notes that most climate models now point to a peak at or above the highest levels observed since 1950.

The SOI captures the air-pressure seesaw between Tahiti and Darwin, and a deeply negative value signals that easterly trade winds are weakening or reversing, allowing warm water to pool off South America. According to Oxford Economics Africa, the reading means the 2026–2027 El Niño could rank among the strongest ever measured. Sea-surface temperatures in the central Pacific are already more than 2 °C above average, a hallmark of a ‘very strong’ event.

For Africa, the consequences are likely to be extreme. El Niño tends to deliver floods to East Africa while plunging Southern Africa and the Sahel into drought. This time the risk is amplified by a positive Indian Ocean Dipole – a neighbouring climate pattern that further dries the Sahel and southern regions. During the last comparable event in 2023/24, maize production cratered by more than 50% in several nations, prompting multiple governments to declare national disasters.

Oxford Economics Africa warns that near-term growth prospects across the Sahel, Southern and East Africa will be weakened as the disrupted rains depress agricultural output, water supply and hydropower generation. Coming on top of already elevated global energy and fertiliser prices, the shock threatens to push food import bills higher and trigger fresh demands for government subsidies and international disaster relief.

What a 'Godzilla' El Niño Means for Africa's Food, Growth and Stability

The SOI reading of -29.1 is not just an abstract climate statistic; it is a powerful leading indicator of economic strain. When the index slumps this far, the historical correlation with drought in Southern Africa and flood damage in Kenya, Tanzania and Ethiopia is painfully strong. The current forecast comes at a uniquely vulnerable moment, with many African states still rebuilding fiscal buffers from the last El Niño and facing stubbornly high costs for imported fertiliser and fuel.

The Agricultural Transmission Mechanism

Rain-fed smallholder farming accounts for a large share of employment and food production across the continent. A sharp decline in rainfall in the Sahel and Southern Africa will cut yields of staples such as maize and sorghum, forcing governments to turn to international markets just as global grain prices remain elevated. Conversely, torrential rain in East Africa can wash away crops, roads and bridges, isolating communities and disrupting supply chains. The World Meteorological Organization’s warning that a positive Indian Ocean Dipole will reinforce these patterns makes a twin shock – drought in the south, floods in the east – the base case.

Compounding Price Pressures

The El Niño arrives at a time when the global energy complex is still tight, keeping fertiliser production expensive. Nitrogen-based fertilisers, critical for maize cultivation, have not returned to pre-crisis levels in many African markets. A poor harvest will therefore collide with high input costs, leaving farmers with less income and governments with larger food-import bills. Oxford Economics Africa makes clear that this double hit is likely to stoke both consumer inflation and fiscal demands for subsidies, at a time when many African central banks are trying to ease monetary policy.

Wider Economic and Humanitarian Fallout

Beyond the farm gate, the disruption to hydropower – a mainstay of electricity supply in countries such as Zambia and Ethiopia – could force a switch to diesel or imported power, raising costs for businesses. Lost agricultural incomes also dampen rural demand, dragging on retail and services sectors. On the humanitarian side, the memory of 2023/24 is fresh: several countries declared disasters only after maize harvests were halved. A repeat this season would strain already stretched aid budgets and could exacerbate food insecurity in fragile states.

How Governments, Businesses and Investors Can Brace for Impact

For governments in Southern Africa and the Sahel:

• Activate drought contingency plans now, prepositioning grain reserves based on the floor of a 50% maize production decline last seen in 2023/24.
• Secure early financing from development finance institutions and multilaterals to avoid having to cut other spending when food import bills spike.
• Review water allocation and hydro-dam management to safeguard power generation through the dry spell, particularly in nations where hydropower exceeds 30% of grid supply.

For East African authorities:

• Accelerate drainage and flood-defence works in urban centres and key transport corridors, anticipating the flooding that typically accompanies a strong El Niño compounded by a positive Indian Ocean Dipole.
• Prepare public health surveillance for waterborne disease outbreaks that often follow flood events.

For businesses and investors with African supply chains:

• Stress-test sourcing plans for maize, sorghum and regional logistics services, assuming a repeat of the 2023/24 supply disruption.
• Hedge foreign-currency exposure where food-import bills are likely to balloon, as a sudden surge in demand for dollars to pay for grain can trigger abrupt depreciation.
• Monitor announcements from weather-sensitive insurers and African sovereign credit issuers, where rating actions could follow a worsening drought outlook.