The Impact of Climate Change on Coastal Erosion: A Case of Bonny and Okrika Communities in Rivers State, Nigeria.

Abstract

Coastal erosion is a major environmental and disaster-risk concern in the Niger Delta, where low elevation, tidal channels, mangrove ecosystems, rapid development and hydrocarbon-related activities interact with climatic and geomorphic processes. This paper examines the impact of climate change on coastal erosion in Bonny and Okrika, Rivers State, Nigeria, using a secondary-data and geospatial evidence-synthesis design. Evidence was assembled from peer-reviewed shoreline-change studies, climate assessments, GIS-based coastal-vulnerability studies and recent Bonny-specific remote-sensing research. The evidence shows that global mean sea level increased by 0.20 m between 1901 and 2018 and that the rate rose from 1.3 mm yr−1 during 1901–1971 to 3.7 mm yr−1 during 2006–2018. Niger Delta shoreline studies demonstrate strong spatial heterogeneity: Afolabi and Darby (2022) found nearly equal shares of erosion and accretion across the wider delta, while recent Bonny-specific work reported net land loss over 2000–2020. A 2024 Rivers State vulnerability assessment ranked Bonny as the most vulnerable assessed coastal area and Okrika third. The paper argues that climate change is a risk multiplier rather than a standalone cause: sea-level rise operates together with subsidence, altered sediment supply, dredging, reclamation, mangrove loss, infrastructure and urbanisation. A publication-grade research protocol is proposed using Landsat/Sentinel-2, DSAS, MNDWI, DEMs, GNSS/InSAR and field validation to quantify shoreline retreat and relative sea-level effects. The study recommends integrated coastal-zone management, mangrove restoration, coastal setbacks, continuous geospatial monitoring, climate-resilient infrastructure and risk-based decisions between protection, accommodation and managed retreat.