Sea Level Rise and Sustainability of the Nigerian Coastal Zone

Abstract

Globally, sea levels have risen in the last century, and various projections suggest substantial increases in sea level due to climate change in this century. In Nigeria, there are no up-to-date sea level rise (SLR) assessments for the coast. Much of the Nigerian coast is low lying with the consequence that a 1 to 3 metres rise in sea level, which may result from eustatic or climate change, will have a catastrophic effect on the human activities in these regions. This study examines the consequences of continued sea level rise with a focus on erosion and inundation for the Nigerian coast and considers the coastal management practices of coastal partnerships (CPs). The Nigerian coast has been delineated according to distinct geomorphological units, which include the Barrier, Mud, Delta and Strand coasts. The Bruun model has been used to compute shoreline recession along the Nigerian coast with the exception of the Mud coast. A Geographic Information System (GIS) was used to develop inundation models and examine the impact scenarios that SLR will have on critical elements, which include land, population, economic activity (Gross Domestic Product), urban extent, agriculture and wetlands with the aid of high quality spatially disaggregated global data. A case study approach was used to assess the management practices of Pro-Natural International Nigeria; Niger Delta Wetland Centre, Niger Delta Development Commission; and Flood Erosion and Coastal Zone Management, Rivers State with the aid of a suite of systemic sustainability appraisal indices. Results indicate that shoreline recession will be mild along the coast while substantial loss due to inundation of the critical elements is expected for all the scenarios considered. The sustainability assessment indicates that the CPs did not meet the required standard for sustainability, however there was evidence of constructive management in some of them. This study has been able to provide up-to-date baseline data concerning the vulnerability of the coast to SLR for the four coastal systems in Nigeria. The coastal sustainability assessment, which is the first ever in Nigeria, reflects the need for corrective measures in the management practices of the CPs to achieve a sustainable coast in the light of coastal hazards.