Over 190 African heritage sites threatened by rising seas this century

As sea levels rise due to climate change, heritage sites all around the African coast will come under increasing risk of flood damage – including Carthage and sites linked to the Ancient Egyptian civilisation

By Michael Marshall

Rising seas will more than triple the number of African heritage sites exposed to the risk of dangerous coastal floods.

By 2050, over 190 of these locations could be in peril. They include the ancient remains of Carthage in Tunisia – which was the capital of the powerful Carthaginian civilisation in the first millennium BC – and a region of the Egyptian Mediterranean coast rich in archaeological sites connected to the Ancient Egyptian civilisation as well as to the Greeks and Romans.

“Understanding climate risk to heritage is critical,” says Nicholas Simpson at the University of Cape Town in South Africa.

Simpson and his colleagues mapped 213 natural sites and 71 cultural sites on the African coast, which were recognised by the UNESCO World Heritage Centre or the Ramsar Convention on Wetlands of International Importance. “We didn’t know the spatial extent, the actual boundaries of most African heritage sites, believe it or not,” he says.

The team then combined this with a state-of-the-art model of sea level rise, which is one of the main consequences of climate change as warming seawater expands and ice sheets melt. Higher seas mean that major coastal floods, when they come, go higher and reach further inland.

At the moment, 56 of the 284 coastal heritage sites the team mapped would be in danger if a once-in-a-century flood struck. However, by 2050 that number will rise dramatically. Under a moderate emissions scenario, 191 will be at risk, and higher emissions will put 198 in danger.

The threatened sites also include Sabratha, a former Roman town in Libya with a spectacular open-air theatre that the Beatles considered as a venue for their final concert, and Kunta Kinteh Island in the Gambia, which has the remains of a fort used by British slave traders.

Elsewhere, up to 44 per cent of the area of the Curral Velho wetland in Cape Verde could be exposed by 2100, under a high-emissions scenario.

The obvious solution is “hard protection strategies” like concrete sea walls, but these may not be the best approach, says Simpson. In some cases, a better tactic would be “hybrid protections” that rely on wildlife, “so just restoring the broader ecology of the area, restoring salt marshes, seagrasses, mangroves”. Buffer zones around the heritage sites are also an option, he says, as is “recognising the local and indigenous knowledge systems that are there”.

It may not be possible to protect everything, says Simpson, but it is essential to try. “I believe there are solutions to climate change if we think hard enough and work hard enough.”

Journal reference: Nature Climate Change, DOI: 10.1038/s41558-022-01280-1