Africa’s coastlines hit record sea level surge during 2023–2024 El Niño

Africa’s coastlines are facing a rapidly accelerating crisis, with the 2023–2024El Niñoevent triggering the most significant sea level surge ever recorded in the region – highlighting adangerous new realityfor the continent’s coastal nations. In a study published inCommunications Earth & Environment, researchers from thedepartment of oceanographyat the University of Cape Town (UCT) analysed more than 30 years of satellite data, spanning 1993 to 2024, across the Atlantic Ocean, Indian Ocean, Mediterranean Sea, Red Sea and surrounding waters. While the global impacts of the 2023–2024 El Niño have been widely documented, its effect on Africa’s sea levels has received far less attention.

Early evidence suggests the event coincided with unusually warm ocean temperatures along almost the entire continent. In some parts of West Africa, sea surface temperatures rose by more than 2°C, they said. As the study notes, “nearly the entire coastline of Africa experienced anomalously high sea surface temperatures in 2023–2024”.

These conditions were accompanied by elevated sea levels, intensifying storm surges, driving saltwater into freshwater systems and accelerating coastal erosion. What remained unclear was how much of these extremes can be directly attributed to El Niño and how much reflects other climate systems or the long-term rise in sea levels. The uncertainty is particularly troubling for Africa, where vulnerability is already high, they say.

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Limited monitoring infrastructure, sparse tide gauge coverage and a heavy reliance on marine resources leave coastal communities exposed. The past two years have underscored this risk, with marine heatwaves disrupting fisheries and compounding food and economic insecurity. The researchers said that Africa’s 38 coastal nations are on the frontline of ocean warming, with parts of the Indian Ocean heating faster than the global average.

Without significant emissions cuts, the study warns, the continent risks exceeding 2°C of warming by the end of the century, placing more than 200 million people at risk. They found that regional sea levels have risen by 11.26cm since 1993 — outpacing the global average — and are accelerating at a rate of 0.14mm per year squared, faster than previously documented.

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