Projected sea surface temperature and sea level rise under different SSP scenarios and coastal vulnerability assessment: case of Nigeria and Benin Republic

The historical and projected changes in sea surface temperature (SST) and sea level rise (SLR) off the coast of Nigeria and Benin Republic and the vulnerability of their coastal areas were assessed in this study. Study uses the HadISST1 of the Met Office Hadley Center observation SST data version 1 at 1° × 1° and the European Space Agency’s ESACCI version 2.0 at 0.25° × 0.25° between 1993 and 2015 and historical Coupled Model Inter-comparison Project Phase 6 (CMIP6) for the bias correction of SST and SLR of MIROC6 of CMIP6 model global climate model using linear scaling method. Spatial and temporal assessments conducted for the near future and far future (FF) under different shared socioeconomic pathways scenarios show SLR projections were highest during September–October-November period and lowest during March–April-May. The highest projected changes in SST of 3.66 °C occurred during June-July–August under SSP 585 in the FF. Projected SSTs are lower near shore compared to outer shore. However, projected SLR are higher near shore, where the SSTs were lower. Average maximum SLR within the study area is expected to be 182 mm while some grids show values of up to 294 mm. Flood vulnerability assessment suggests moderate to low vulnerability classes at the coast with little areas with high vulnerability class. The West coast of Nigeria show low to high classes with small patches of very high class. The highest vulnerability to floods are at the east coast of Nigeria and the lowest at Benin Republic.