The Impact of Climate Change and Sea Level Rise in the Nigerian Coastal Environment

Abstract

The study was carried out to assess the impact of climate change and sea level rise around the Nigerian coastal environment. Tidal data (2013,2015,2017-2021) from semidiurnal tides for six stations (Apapa, Benin, Akassa, Bonny, Brass, Calabar) and Mean Sea Level data (1989-1992) for Bonny were analyzed for trends using Mann-Kendall test (non-parametric) and Sen’s slope for the purpose of forecasting future variations. The Mann-Kendall Zs values for the stations indicated a statistically significant trend in Bonny, Calabar, Akassa and Brass stations during High Waters(evening) with Akassa station having the strongest trend. The p-value for the stations during High Waters(evening) also indicates the presence of a trend in the same four stations. Apapa and Brass stations displayed higher Sens’s slopes of 0.00013 and 0.00014 respectively while Bonny and Calabar stations displayed lower Sen’s slopes of -0.00057 and -0.00056 respectively. The analysis of the monthly Mean Sea Level for Bonny estuary gave a Z value of 0.217 and positive Sen Slope value of 0.0045m resulting to a non- significant trend although, indicating a tendency for the sea level to rise over time at the rate of 45mm per annum. The results suggest a statistically significant trend in sea level. These observations can affect both the livelihood and natural environment of coastal areas causing widespread elevation in oceanic levels, and perhaps lead to coastal strain and infiltration of saltwater. Hence, it is imperative to adopt mitigation and adaptation measures like reduction of greenhouse gas emissions, construction of seawalls and restoration of wetlands.