Sea levels around Africa are rising faster than ever before. A new study reveals that 2023 marked a critical turning point. Increasing sea level threatens coastal cities, ecosystems, and millions of people.
Roshin P. Raj and Antonio Bonaduce from the Nansen Center co-authored a study that outlines the changes to the sea level along the African coastline. They utilized high-resolution satellite observations of the past three decades. They found that since 1993, the oceans surrounding the continent have risen with an accelerating pace: from less than 1 millimeter per year in the 1990s to more than 4 millimeters per year over the past decade. Between 2022 and 2023 alone, levels jumped nearly 2 centimeters, which is the second-largest annual increase ever recorded.
What is at stake?
More than 250 million people live along Africa’s coasts, many in rapidly growing cities with limited protection. Rising sea levels endanger homes, infrastructure, freshwater supplies, fisheries, and ecosystems like mangroves and coral reefs. This is no longer a future scenario; changes are unfolding today, with coastlines and coastal populations already feeling the strain.
Why is this happening?
The main driver for sea-level rise is global warming. Oceans absorb over 90% of the excess heat trapped by greenhouse gases, causing seawater to expand. This is called thermal expansion. At the same time, melting glaciers and ice sheets in Greenland and Antarctica add enormous volumes of water. Today, more than 80 percent of Africa’s sea-level rise comes from melting ice, with the remainder reflecting the thermal expansion.
2023 marks a turning point
With global temperatures reaching about 1.3 °C above pre-industrial levels in 2023, the trend shows no sign of slowing. That year stands out as the most extreme sea-level event ever recorded around Africa. Nearly 40% of the surrounding ocean reached record-high levels, marking a clear break from previous patterns. This anomaly was not only large in scale but persistent, even after accounting for global signals. It was driven by strong regional forcing on top of an already accelerating rise. We can expect to see further increases in sea-level rises along the African shores.
Uneven impacts across the continent
Due to global warming, sea-level rise is accelerating along Africa’s coasts, but not in the same way everywhere. Some regions are seeing sharp increases driven by ocean warming, while others are affected more by changes in salinity or the addition of water from melting ice sheets. Local factors such as land subsidence and extreme weather make the picture even more complex. These differences mean that the risks, from flooding and erosion to damage of ecosystems, vary widely across the continent. The study makes one thing clear: adaptation cannot be a one-size-fits-all approach. Each region will need tailored strategies to cope with these growing challenges.
A call for region-specific adaptation
Africa contributes less than 4% of global carbon emissions, yet faces some of the most severe consequences. The study highlights the urgent need for adaptation strategies designed for regional conditions. International support will be crucial to help coastal communities prepare for the not-so-distant future.
Key researchers: Antonio Bonaduce, Roshin P. Raj
