Evaluating the extreme precipitation indices and their impacts in the Volta River Basin in West Africa from a nexus perspective

Changes in global or regional climate in recent decades have significantly impacted various aspects. Africa, with immense concern, is facing the consequences of extreme precipitation on socio-economic activities such as poverty, hydropower generation, and many more. This paper aims to evaluate the precipitation extremes in the Volta River Basin (VRB) in West Africa using the extreme climate indices proposed by the Expert Team on Climate Change Detection and Indices (ETCCDI). The precipitation data for the analysis were obtained from Climate Forecast System Reanalysis (CFSR) for 36 years from 1979 to 2013 at a spatial resolution of 0.5° at the tropics and 0.25° at the equator. The temporal distribution of average precipitation in the basin decreases at the rate of 15 mm per year, while the maximum and minimum temperatures increase at the rate of + 0.066 °C and + 0.019 °C, respectively. In addition, the temporal distribution of precipitation indices showed that the dry days (+ 1.1 days/year) are increasing, and the wet days (− 0.25 days/year) are decreasing. The dry years are more pronounced in the northern region of the basin, while the wet days are more pronounced in the southern. The increasing trend of the dry years and decreasing trend of the wet years will lead to face drought events in the future, affecting rain-fed irrigation productivity and hydropower production thereby affecting the nexus of water, agriculture, and socio-economic. With further increases in the dry events in the basin, adaptive climate measures need to be addressed to minimize climate-related hazards. This could be achieved by conducting nexus-based research considering climate science, social science, economics and the environment.