• Sea levels off African coasts have risen at a rate four times faster since 2010 than in the 1990s, driven mainly by ice-sheet melt.
• About 80% of the rise comes from added water rather than thermal expansion, a pattern that differs from the global average.
• Up to 117 million Africans could face impacts from a 0.3-meter sea-level rise by 2030, despite Africa producing only about 4% of global CO₂ emissions.

Sea levels off Africa’s coasts have increased at a pace four times faster since the 2010s than during the 1990s, driven largely by melting ice sheets, according to a scientific report published on December 15, 2025, in Communications Earth & Environment.

The study shows that Africa, despite contributing only about 4% of global carbon dioxide emissions, faces accelerating coastal risks that underline the need for increased international climate finance and technology transfers to support local adaptation efforts.

The report, titled “Accelerating sea level rise in Africa and its large marine ecosystems since the 1990s,” analyzes African marine ecosystems over a 31-year period from 1993 to 2023 using satellite altimetry data.

Researchers from Africa and Western countries found that average sea level along Africa’s coasts rose by about 10.2 centimeters over the period, equivalent to an annual average of 3.31 millimeters. This figure broadly matches the global average, but Africa shows a sharper acceleration beginning around 2010.

During the 1993–2002 decade, sea levels rose by an average of about 0.96 millimeters per year. The pace then increased to an average of 2.93 millimeters per year between 2003 and 2012.

The 2013–2023 period recorded an average rise of 4.34 millimeters per year. This annual pace, four times faster than that of the first decade covered by the study, represents a new baseline rather than a temporary spike, the authors said.

The scientific community broadly recognizes two main drivers of sea-level rise linked to climate change. Sea levels increase either because additional water enters the oceans, mainly from melting ice sheets, or because existing seawater expands as it warms or becomes less saline.

To quantify these effects, the authors tracked temperature and salinity changes at multiple sites using floating instruments. Their analysis shows that thermal expansion accounts for only about 20% of sea-level rise off African coasts.

By contrast, about 80% of the increase over the study period resulted from added water, primarily from ice-sheet melt.

Red Sea and Guinea Current face the steepest increases

Globally, added water and thermal expansion contribute almost equally to sea-level rise. Africa deviates from this pattern because of local oceanographic conditions, including cold-water upwelling that keeps some surface waters cooler and high salinity along the Mediterranean coast, as well as the gravitational and rotational redistribution of meltwater.

Sea-level rise also varies significantly across African regions. The largest increases occurred in the Red Sea and along the Guinea Current, a slow-moving warm current flowing eastward along West Africa’s coast.

The Mediterranean region experienced smaller increases because rising salinity makes its waters denser.

The report warns that rising sea levels pose a major threat to coastal ecosystems and the livelihoods of roughly 250 million people living in Africa’s coastal zones.

The impacts include recurring floods, coastal erosion, biodiversity loss, infrastructure damage, community displacement, and saltwater intrusion into freshwater aquifers.

Vulnerability remains especially acute in densely populated megacities such as Lagos, Alexandria, and Dar es Salaam. In Lagos alone, land subsidence could double flood frequency by 2050, putting more than 12 million residents at risk.

Projections show that up to 117 million Africans could face impacts from a 0.3-meter sea-level rise by 2030. Rapid urbanization and weak coastal planning in many cities amplify these risks and create cascading, interlinked hazards.

Africa’s minimal contribution to global CO₂ emissions contrasts sharply with the scale of the climate impacts it faces. The report argues that accelerating sea-level rise, from less than 1 millimeter per year in the 1990s to more than 4.3 millimeters per year in recent years, suggests that current adaptation strategies may prove insufficient without stronger international support.

This article was initially published in French by Walid Kéfi 

Adapted in English by Ange J.A de BERRY QUENUM