African Sea Levels Rising Faster Than Global Average, Study Finds
Satellite data spanning three decades shows sea levels around Africa are rising at a rate that exceeds the global average, heightening risks for the continent’s extensive coastal populations. A new analysis of ocean height measurements from 1993 to 2024 indicates that African marine waters have increased by approximately 11.26 centimetres over the period, with an average annual rise of 3.54 millimetres—slightly above the global mean of 3.45 mm/yr.
The research, led by oceanographer and geophysicist Franck Ghomsi of the University of Cape Town’s Nansen Tutu Centre, identifies a concerning acceleration in the pace of rise, particularly in specific regional hotspots. This long-term trend is driven primarily by ocean warming—which causes water to expand—and the addition of meltwater from ice sheets, both consequences of human-induced climate change.
The Western Indian Ocean, near Mozambique, Madagascar, and the Comoros, shows the highest acceleration at 0.16 mm per year squared, with a current trend of 3.88 mm/yr. The Eastern Central Atlantic, including the Gulf of Guinea and waters off West African nations like Senegal and Nigeria, follows closely at 3.90 mm/yr. These areas experience both the fastest rise and the sharpest acceleration, marking them as priority zones for monitoring and adaptation planning.
The study also isolated the impact of short-term climate cycles. The 2023-2024 El Niño event, combined with other oceanic patterns, produced the largest recorded sea level spike in African waters—an anomaly of 27 millimetres. Thermal expansion from exceptionally warm surface waters accounted for over 70% of this extreme rise. Crucially, this spike occurred atop an already elevated baseline, meaning each new event builds on decades of prior increase. In one year alone, the Western Indian Ocean surged by 3.87 centimetres, nearly one-third of its total rise since 1993.
Africa’s 38 coastal nations are home to over 200 million people living near the shore. The steady encroachment of the sea threatens these communities with increased flooding, coastal erosion, and saltwater intrusion into freshwater and agricultural land. Rising and warming seas also disrupt vital fisheries, impacting food security and livelihoods for millions.
Addressing the crisis requires a two-pronged approach. Globally, drastic reductions in carbon emissions are essential to slow ocean warming. Regionally, African nations need expanded ocean monitoring for early warnings and investment in coastal protection, including nature-based solutions like mangrove restoration. Initiatives such as the World Bank-supported West Africa Coastal Areas Management Program offer models for coordinated infrastructure and policy responses.
The findings underscore that the “normal” sea level today is already centimetres higher than a generation ago. Without sustained global climate action and targeted local adaptation, the swelling ocean will continue to reshape Africa’s vulnerable coastlines.
