APPRAISAL OF CLIMATE CHANGE-INDUCED DISASTERS IN SOUTH WESTERN COAST OF NIGERIA

Abstract

This study appraised the impacts of climate change-induced disasters in Southwestern Coast of Nigeria, with a view to proffering sustainable disaster mitigating strategies in the study areas. The study focused on the coastal areas of Ondo State (Ilaje Local Government Area) and Lagos State (Eti-Osa Local Government Area). The climate change-induced disasters appraised in the study included temperature rise, flooding and coastal erosion. The research was conducted using Questionnaire administration, Geographic Information System (GIS), Archival Climatic data and Sea Level Rise (SLR) data. The study was a survey design that adopted a mixed method that combines qualitative and quantitative approaches and 988 copies of questionnaire were administered to collect data from the study areas using Systematic Sampling. However, only 702 copies were retrieved for analysis. The retrieved copies were analyzed using SPSS 8.1 while the hypotheses were tested using Mann Kendall Trend Analysis and Multivariate Regression Analysis. Temperature and rainfall data were used to investigate the trend of climate variability between 1980 and 2015. Satellite imageries and questionnaire were adopted to examine flood vulnerability and coastal erosion menace. Digital Elevation Model (DEM) and slope maps were generated from the topographical map of the study areas. Landsat TM of 1984, ETM+ 1999/2000 and OLI 2015 of Ilaje and Eti-Osa LGAs were used while all geo-processing operations and analyses were carried out in ILWIS 3.1 and ArcGIS 10.2 software. Overlay of imageries of the study areas at different epochs was done to get the changes in the coastline. The Digital Shoreline Analysis System (DSAS) was used for the coastal erosion analysis, Net Shoreline Movement (NSM) and End Point Rate (EPR) model was also developed to predict the extent of future coastal erosion between 2015 to 2030 in the study areas. Findings revealed that climate change menace was evident in the study areas due to variation in the rainfall and temperature distributions. The study revealed that the study areas were vulnerable to flooding due to its proximity to the Atlantic Ocean with low-lying topography, high rainfall and lack of drainage and high rate of urbanization especially in Eti-Osa LGA. Furthermore, the study revealed that high rate of coastal erosion was pronounced in Ilaje LGA between 1999 to 2015 and in Eti-Osa LGA between 1984 to 2000 while coastline gain was pronounced between 2000 to 2015 in Eti-Osa LGA. The predicted coastal erosion revealed that between 2015 to 2030, coastal erosion would be higher in Ilaje LGA than Eti-Osa LGA. The study revealed that infrastructure have been destroyed and many residents rendered homeless by flooding. Coastal erosion had carried away several buildings, and some dwellers relocated to safer environment. To reduce the effects of climate change and its related disasters in the study areas, recommendations were made. These included re-greening of the coastal communities, mapping of disaster prone communities and exploration of GIS Technology in Disaster Management, adoption of hard and Soft Engineering options for Coast Protection, adherence to Town Planning laws, adequate funding, embarking on waterfront renewal strategy, and relocation.