COASTAL VULNERABILITY ASSESSMENTS AND ADAPTATION TO CLIMATE CHANGE AND EXTREME EVENTS ALONG THE GULF OF GUINEA

Abstract

The Gulf of Guinea (GoG) of West Africa had been the most climate-vulnerable region to coastal hazards due to its low-lying terrain, frequent occurrences of extreme events as a result of climate change. Coastal flooding, Storm surges and Marine heat waves are among the hazards posed to millions of inhabitants living along the GoG, thereby displacing people from their homes. The aim of the study was to assess the vulnerability of the Gulfof- Guinea (GOG) to changing change and extreme events towards regional adaptation. Therefore, this study experienced the trends and spatial patterns of climatic variables were assessed over the period 1851 – 2020 while projected (2021-2060) impacts from climate change on coastal systems were estimated. Four coupled model intercomparison project phase 6 (CMIP6) Global Climate Models (GCMs) under respectively concentration pathway (RCP8.5) emission scenarios were adopted in this study. The daily and monthly downscaled archived climatic datasets were retrieved online for rainfall, runoff, sea surface temperature, significant wave height and swells, u-v wind components, as well as sea level heights. The results from the climate change scenarios predict an increase in rainfall across all future periods and under both emission scenarios, with the highest projected increase during the last three decades of the century. Under the RCP 8.5 emission scenario, the rainfall in Lagos, Badagry and environs was projected to increase by about 4.1% with expected number of extreme flooding occurrences mostly in the months of July, September and October. Other coastal communities are also expected to record relatively high land surface temperature during the months of January – March and windy storms between July-September. The 12-month Standard Precipitation Index (SPI) under the RCP 8.5 emission scenarios predicted an exceedance in the extreme wet viii threshold (i.e., SPI > 2) during all future periods (2021-2060) and across major parts within the region. In addition, the social survey conducted in twelve cities across the four countries (Ghana. Togo, Benin Republic and Nigeria) resulted into a total number of 594 out of the 600 copies distributed during the survey. The results from the outputs then suggested that households were vulnerable to climate change induced extreme events, currently with low coping capacity. On the socio-economic importance of the inhabitants along the coastal communities, the respondents affirmed that the various communities had in one time experienced the impacts of the storm surges, flooding and marine heat waves, despite their various level of educational awareness. Residents along the river banks, lagoons, creeks and those near the estuaries near often experience increased frequencies of coastal flooding, with great impacts and severe damages to lives and properties. Hence, the integrated coastal vulnerability index (ICVI) map over the region had showed how a consistent coastal vulnerability analysis and methodology may serve to collect, analyze and visualize coastal features and support risk management strategies. Furthermore, discrepancies existed between global and regional climate models on the projected change considered and their characteristics over the region. The study findings suggest an increasing risk of coastal hazards within the projected periods. The findings could be useful to policymakers for the formulation and planning of coastal hazard mitigation and adaptation measures.