Present and Future Extreme Coastal Water Levels and Flooding Extents on Nigeria's Mahin Mud Coast

In the context of global warming marked by rising sea levels and extreme meteorological events, it is imperative to gain a comprehensive understanding of coastal vulnerability to flooding, as this knowledge is essential for safeguarding both communities and ecosystems. Using high-resolution satellite-derived digital elevation models and global ocean reanalysis, the degree to which a part of Nigeria's Mahin mud coast in the Gulf of Guinea of the North Atlantic Ocean is vulnerable to coastal flooding is assessed. The results show that the study area is at risk of being affected by both present and future extreme coastal flooding events, which poses a significant threat to coastal integrity and stability. It faces potential deterioration in coastal flooding due to future SLR consequences. Mean ECWLs are projected to increase from 1.6 m in 1993-2015 (present) to 2.1 and 2.2 m by 2050, with further acceleration to 2.4 and 2.85 m by 2100, under SSP2-4.5 and SSP5-8.5, respectively. This increases the risk of extreme coastal water levels, with land submerged by 125 km² and 170 km² under SSP2-4.5 and SSP5-8.5 climate scenarios by 2100. The study area's exposure to ECWF increased from 2181 to 2312 buildings in 2050 and 3003 in 2100 under SSP2-4.5 and SSP5-8.5, with potential exposure increasing from 24,856 to 128,083 people in 2100 under SSP5-8.5, highlighting the area's high vulnerability to sea level rise. It is therefore crucial to develop a sustainable strategy to protect the mud coast from degradation and promote sustainable development, thereby mitigating the present and future coastal retrogradation.