Once one of the most magnificent cities of the ancient world, Carthage was razed to the ground by the Romans in 146BC. Now its ruins, a Unesco World Heritage site, face new threats wrought by climate change: a rising sea level, increased salinity and intensified wind erosion.
The erosion from saline winds is clearly visible at the Baths of Antoninus, one of the three largest Roman bath complexes ever built and the only one on African soil. Numerous columns are cordoned off for their protection. At the nearby Punic Port site along the coast, which serviced Carthaginian and Roman ships, parts of the port island can be seen crumbling into the sea.
“These monuments are under stress from both time and climate, and protecting them requires close surveillance and timely interventions,” says Lorenzo Nigro, the director of the Archaeological Mission of Sapienza University of Rome to Carthage. “Climate change is today one of the most serious and concrete threats to archaeological heritage, especially in coastal areas of the Mediterranean.”
The issue is beginning to raise the alarm at Unesco. At the 47th session of the World Heritage Committee in July, Audrey Azoulay, Unesco’s director-general, highlighted climate change as one of the great dangers facing global heritage. She cited a recent joint report from Unesco and the World Resources Institute, which found that nearly three-quarters (73%) of World Heritage sites are highly exposed to water-related hazards, such as drought, water stress or coastal flooding.
A major study published in the journal Nature Climate Change in 2022 mapped 284 cultural and natural heritage sites along Africa’s 300,000km coastline. It found that 56 (20%) were already facing risks from coastal flooding and erosion, and this number was expected to triple to more than 190 by 2050 due to rising greenhouse gas emissions. Sea-level rise is caused by global warming melting ice caps and hotter temperatures causing water molecules to expand.
Other African sites at risk, according to the researchers, include Kunta Kinteh Island in The Gambia, one of the first cultural exchange zones between Africa and Europe. It was acquired by the Portuguese in 1456 and became a key site in the slave trade, marking an “important, although painful, period of human history”, according to Unesco.
Another endangered site is the second-century trading port of Sabratha in modern-day Libya, whose magnificent amphitheatre was almost chosen as the location for the final performance by The Beatles, before they opted for the rooftop of their central London headquarters instead.
Military might
Founded by Phoenician settlers in modern-day Tunisia, the Carthaginian republic was one of the longest lived in the ancient Mediterranean. Such was its wealth, sea-faring strength and military might it occupied large swathes of Roman Italy through its most famous military general, Hannibal, who invaded by marching his army —including north African war elephants—over the Alps.
Despite occupying parts of southern Italy for 15 years, Hannibal was unable to conquer Rome. Three separate Punic Wars fought between the two powers consisted of 43 years of active warfare over a 118-year span. They culminated in the three-year siege of Carthage, its destruction by the Romans and the death or enslavement of more than 100,000 Carthaginians. Carthage was eventually rebuilt to become a major centre of Roman Africa. Arab invaders then destroyed it again at the end of the seventh century.
Remains that have stood for more than 2,000 years are now threatened by a new enemy. “At Carthage, mitigation measures are urgently needed,” Nigro says. “In some areas, particularly around the Punic Ports and the Baths of Antoninus, it will likely be necessary to implement a combination of actions: partial reburial of fragile remains, consolidation of Roman masonry—which still demonstrates remarkable resilience—and installation of protective shelters to shield monuments from the most aggressive elements.”
The researchers of the study published in Nature Climate Change, who included 13 academics from the fields of climate change, heritage and coastal engineering, found that if the world can limit greenhouse gas emissions, the impact on these heritage sites can be reduced.
“How we respond to climate change matters for heritage,” says Nicholas Simpson from the University of Cape Town’s African Climate and Development Initiative, one of the authors. “If climate change mitigation reduces greenhouse gas emissions from a high to a moderate pathway by 2050, the number of highly exposed heritage sites can be reduced by 25%.”
Nigro says that combining emissions cuts with practical, on-site adaptation measures is the key to solving the climate-induced heritage emergency. “The international community must face the reality that cultural heritage is on the front line of the climate crisis,” he says. “Governments must of course reduce carbon emissions, but they must also invest significantly more in heritage protection. This includes funding for scientific research, site monitoring, local training in conservation techniques and emergency planning.”
He hopes that the growing body of research will be a wake-up call for the protection of Carthage and similar ancient treasures. “Unesco and other international bodies are already making efforts, but these must be scaled up and better integrated with climate adaptation policies,” Nigro says. “Archaeological heritage is not just a legacy of the past; it is a resource for sustainable development, education and identity. Protecting it from climate change is a global responsibility.”
