The global average sea level is expected to rise by up to half a metre by 2050 and up to two metres by 2100. This is due to the expansion of seawater from increasing temperatures caused by global warming and melting glaciers and ice sheets, which cover 10% of the Earth’s surface.
Many of Africa’s largest and most densely populated cities, including Lagos, Abidjan and Accra, are located along its low-lying West Coast. They are vulnerable to climate change impacts such as coastal flooding and pollution, which cost the continent around US$4 billion in annual economic losses. These rapidly expanding littoral metropolises are threatened by land mass erosion, coastal flooding and storm surges caused by rising sea levels.
These cities contribute significantly to the region’s economy, generating 56% of its gross domestic product, according to a 2020 World Bank report. They also offer vast wetlands, marine resources, opportunities for tourism, and oil and gas reserves.
The prospects for sustainable development along West Africa’s coast are complicated. The population trajectory is forecasted to exceed anywhere else in Africa. It will be accompanied by rapid coastal urbanisation, heightened demand for water and land, and destructive activities like sand extraction – all as sea levels rise.
The Intergovernmental Panel on Climate Change’s (IPCC) Sixth Assessment Report suggests that by 2030, around 116 million Africans could live in densely populated, low-lying coastal areas. The IPCC warns that while coordinated action is needed to address rising sea levels, not enough tangible adaptation measures have been implemented.
The Africa Climate Mobility Initiative converts sea level projections into estimates of potential population exposure to guide policy interventions. These projections must be mainstreamed into various levels of policymaking to be implemented. If adaptation measures aren’t implemented, Africa could face annual damages costs of up to US$10 billion from flooding alone by 2100.
West Africa’s coastline averages about 300 metres above the sea along the Atlantic Ocean, with few mountains, putting these countries at risk. In Ghana, rising sea levels threaten coastal communities in low-lying areas such as Accra, Keta and Takoradi. Senegal’s coastal communities, such as Saint-Louis, Dakar and Ziguinchor, are also vulnerable.
Once sea levels rise, these communities could be displaced by inundation and erosion, losing homes, infrastructure and agricultural land. This exacerbates socio-economic inequalities and public health crises emanating from damage to drainage systems. Implementing long-term solutions, including improved urban planning, resilient infrastructure and planned relocation where adaptation isn’t possible, is crucial to ensure the safety of affected areas.
The impact of rising sea levels is both an environmental and an economic problem. Coastal infrastructure such as ports is critical for the region’s economy, as it supports tourism, fisheries and trade. The World Bank estimates that Côte d’Ivoire lost up to US$2 billion – nearly 5% of the country’s gross domestic product – in damages from rising sea levels in 2019 alone.
Changing coastal ecosystems due to rising sea levels also adversely affect fish populations, diminishing catch potential, compromising food security and jeopardising coastal communities’ socio-economic stability.