Empirical model for the assessment of climate change impacts on spatial pattern of water availability in Nigeria

Abstract

Rising temperatures and changing rainfall patterns due to global warming would affect sustainability in water resources in many regions. This change would impact several sectors, particularly the agricultural and water resources. The major objective of the present study is to model the impacts of climate change on spatial variability in water sustainability of Nigeria. Gauge based gridded rainfall data of global precipitation climatology centre (GPCC) and temperature data of climate research unit (CRU) for the period 1901–2010 and total water storage (TWS) anomaly data of Gravity Recovery and Climate Experiment (GRACE) for the period 2002–2016 were used for this purpose. The concept of reliability-resiliency-vulnerability was used for the assessment of sustainability in water resources. Machine learning models were used for the development of empirical models for the simulation of TWS from GPCC rainfall and CRU temperature. Finally, the multi-model ensemble mean projections of rainfall and temperature of four GCMs namely MRI-CGCM3, HadGEM2-ES, CSIRO-Mk3-6-0 and CESM1-CAM5 were used in the model for the assessment of climate change impact on water sustainability. The results revealed the declination of TWS in Nigeria up to -12 m during the rainy periods in some parts. Spatial assessment of the changes in TWS for the future shows the northeast, southeast and south-south parts would mostly experience decreases in TWS. Water sustainability will be low in these areas and some other parts of the country for the future.