KNOWLEDGE SHEET 6 T H E E F F E C T S O F C L I M AT E C H A N G E O N C O A S TA L E R O S I O N I N W E S T A F R I C A KNOWLEDGE SHEET 6 The Effects of Climate Change on Coastal Erosion in West Africa T he effects of climate change—from changing precipitation patterns to rising seas—will exacerbate the coastal erosion already affecting West Africa, increasing the exposure and vulnerability of the people and assets located there. Given the importance of the coastal zone to the region as a whole, it is critical that policymakers consider the effects of future climate change in the decisions they make today. Challenges Many factors, both natural and human related, drive KEY CLIMATE IMPACTS ON COASTAL coastal erosion. The main causes are the depositing and EROSION removal of sediment, which occur via natural processes, such as coastal drift and river discharge. • Rising sea levels, intensifying storm surge, and extreme precipitation are likely to accentuate Human activity can exacerbate erosion in multiple ways. coastal erosion events, with significant socio- It can affect the removal of sediment, through direct economic impacts. extraction or the creation of surfaces that disrupt the natural processes. Much more important is the disruptive • Changing precipitation patterns could decrease effect on the supply of sediment, caused largely by dams, the overall rainfall volumes in West Africa, which interrupt the natural flow of rivers, preventing sed- which would further reduce the flow of rivers in iment from reaching coastal areas. The decline in coastal the region, thus leading to a decrease in sed- mangrove populations, which trap sediment where it is imentation deposits, in turn causing increased needed also contribute to coastal erosion, and climate erosion rates. change can affect natural resources such as these through • The combination of higher temperatures, changing temperatures, increasing salinity of groundwater increasing salinity of coastal estuaries and and coastal estuaries, and alterations in river dynamics. groundwater resources, and alterations in river dynamics from changes in rainfall may continue The combination of these factors has led to severe land to exacerbate the loss of natural ecosystems and and shoreline loss. The socioeconomic impacts are massive, resources located along the coast. because coastal areas are home to millions of people and billions of dollars of infrastructure. In addition, rising sea levels, intensifying storm surge, and extreme precipitation are likely to accentuate coastal erosion events. will not be uniform across regions, however, because By 2100 average sea levels are projected to rise 0.26–0.63 of factors such as land subsidence. Sea levels along the meters in low-emissions scenarios and 0.33–0.82 meters West African coast are expected to rise faster than the in high-emission scenarios (IPCC 2013). Sea-level rise global average (UEMOA 2010). In addition, changing KNOWLEDGE SHEET 6 T H E E F F E C T S O F C L I M AT E C H A N G E O N C O A S TA L E R O S I O N I N W E S T A F R I C A precipitation patterns could decrease annual rainfall in the increasing stress on natural resources. Climate change region, reducing river flows and the concomitant delivery could exacerbate these trends, as droughts inland—which of sediment to coastal areas. are expected to become more frequent and intense as a result of higher temperatures and changing precipitation Population growth, urbanization, and migration have patterns—drive rural populations from the hinterland led to the concentration of populations, infrastructure, toward the urban centers of the coast in search of eco- and economic assets in the coastal areas of West Africa, nomic opportunity. Solutions In thinking about the resilience measures available to Development of long-term land use plans that account address the challenges facing West African coastal areas, for climate change and direct development away from it helps to use a conceptual framework. One intuitive areas with high exposure to climate-related hazards will method for doing so groups potential measures into be critical. Coupled with conservation efforts, particularly five categories: for mangrove forests, this will help reduce coastal erosion. • policy development and planning Regional cooperation is challenging, but it has been successful in many places, particularly where the issue • hard measures (infrastructure) addressed presented an existential challenge to the coun- • soft measures (including ecosystem and community- tries affected. Efforts to build trust and coordinate efforts based adaptation) will help policymakers protect the lives and livelihoods of the people in the region and allow their countries to build • capacity building on the development gains made in recent years rather than see them rolled back as a result of climate change. • knowledge management and climate information services REFERENCES Resilience measures can be integrated into programs and investments by modifying the intervention to account for IPCC (Intergovernmental Panel on Climate Change). climate change—by scaling up monitoring systems for 2013. “Summary for Policymakers.” In Climate Change climate events or changing the design of infrastructure 2013: The Physical Science Basis. Contribution of to account for future floods, for example. Working Group I to the Fifth Assessment Report of the Intergovernmental Panel on Climate Change. Local adaptation actions are important to the communities Cambridge: Cambridge University Press. they serve, but they are a piece of a much bigger puzzle. UEMOA (West African Economic and Monetary Union). Long-term resilience needs to be addressed at the national 2010. Regional Shoreline Monitoring Study and Drawing and regional levels, because activities in one part of the up of a Management Scheme for the West African region can affect areas elsewhere. Coastal Area. Regional Diagnostic. The West Africa Coastal Areas Management Program (WACA) is a convening platform that aims to assist West African countries to sustainably manage their coastal areas and enhance socio-economic resilience to the effects of climate change. The program also seeks to facilitate access to technical expertise and financial resources for participating countries. www.worldbank.org/waca 3/2016