The ruins of Tipasa in Algeria, home to vestiges of the ancient Punic and Roman civilisation, and the North Sinai Archaeological Sites Zone that cleared the way for the military expeditions of Egyptian pharaohs on their way to Canaan and Asia, are in danger.
They are among 56 heritage sites on the African coast exposed to a one-in-100 year coastal extreme event, driven by climate change, according to a new study published this month in Nature Climate Change.
An international team of climate risk and heritage experts, including Nicholas Simpson of the African Climate and Development Initiative at the University of Cape Town, has, for the first time, provided a comprehensive assessment of exposure of African cultural and natural heritage sites to extreme sea levels and erosion associated with accelerating sea level rise.
In a year-long effort, the experts identified and mapped the physical boundary of 284 African coastal heritage sites — 213 natural and 71 cultural.
The team noted how, in contrast to other continents, few studies have assessed climate change risks along the 300 000km African coastline, which spans 39 countries. “Even sparser is information about the future of the continent’s cultural and natural heritage sites, many of which are found in the coastal zone. Heritage sites have important cultural, ecological, historical, social and economic value. Yet climate change hazards such as river floods,heatwaves and wildfires threaten heritage globally.”
Multiple heritage sites, including World Heritage Sites of Outstanding Universal Value, are located in the low-lying coastal zone.
“Sea levels have been rising at a faster rate over the past three decades compared with the 20th century, a process that is expected to gather pace through the 21st century. Together with changing weather patterns, this is expected to intensify coastal flooding and coastal erosion, exacerbating damages to coastal zone assets,” the experts said.
The number of sites threatened by a 100-year coastal extreme event is projected to more than triple under moderate emissions, reaching 191 by 2050, according to the study. Several countries are projected to have all their coastal heritage sites exposed to the 100-year coastal extreme event by the end of the century, regardless of the scenario. This includes Cameroon, Republic of the Congo, Djibouti, Western Sahara, Libya, Mozambique, Mauritania and Namibia.
“Under the worst-case scenario, this is also true for Côte d’Ivoire, Cabo Verde, Sudan and Tanzania. This is very concerning because none of these countries currently demonstrate adequate management or adaptive capacity to anticipate or establish heritage protections commensurate with the severity of these hazards,” the study said.
Small island heritage sites such as Kunta Kinteh Island in The Gambia and the Aldabra Atoll, which is part of the Outer Islands of the Seychelles and is the world’s second-largest coral atoll, are particularly at risk. Both could see significant amounts of their extent exposed by 2100 under high carbon emissions “raising questions of their survivability under climate change”.
Africa is home to some of the most diverse cultural and biocultural heritage in the world, internationally recognised for its uniqueness and “outstanding universal value”.
“Heritage sites have continuously served as ‘living’ heritage and therefore are deeply interwoven with the people’s identity and tradition, are essential for social wellbeing, safeguarding traditional knowledge and livelihoods, and constituting a prerequisite for sustainable development,” the experts said. “Yet, we find that one of five coastal African heritage sites are already at risk from a 1-in-100-year extreme sea level event, a number that is projected to almost quadruple by the end of the century.”
How much area a heritage site can lose to flooding and erosion and still maintain its cultural, ecological, indigenous and economic value is a critical question for all protected areas and World Heritage Sites, and demands site-specific local studies, the authors assert.
“The same applies to the capacity of natural coastal systems to adapt and absorb other external shocks, such as changes in salinity, which remains unknown. Anthropogenic [human-caused] modification of coastal processes will also affect natural systems’ responses to shoreline change,” said the study.
The number of highly exposed sites can be reduced by 25% if climate mitigation successfully reduces greenhouse gas emissions from a high-emissions pathway to a moderate emissions pathway by 2050.
“As understanding of climate risk to heritage grows, there is potential for these exposure findings to raise public concern and mobilise rapid and ambitious greenhouse gas mitigation to reduce overall risk and potential loss and damage,” the experts said.
Their findings help prioritise sites at risk and highlight the need for immediate protective action for African Heritage Sites, the design of which requires in-depth assessments of vulnerability and adaptation options, according to the study.
“Urgent climate change adaptation for heritage sites in Africa includes improving governance and management approaches; site-specific vulnerability assessments; exposure monitoring and protection strategies including ecosystem-based adaptation.”