The consequences of the IPCC AR5 RCPs 4.5 and 8.5 climate change scenarios on precipitation in West Africa

Abstract

Projected changes in precipitation for the 21st century using Representative Concentration Pathways (RCPs) 4.5 and 8.5 Wm−2 are analysed over a limited domain of West Africa. These analyses are done to help address the challenges of climate change impact assessment over this highly vulnerable region. Thirty general circulation model historical precipitation simulations are evaluated using mean absolute error with optimum value of two standard deviations in CRU data. Relatively skillful models for precipitation simulation over Western West Africa (WWA), Central Guinea Coast (CGC), Eastern Guinea Coast (EGC), Lower Eastern Sahel (LES), and Eastern Sahel (ES) are selected for precipitation projection analysis. LES and ES are expected to be significantly wetter throughout the 21st century with reference to 1985-2004 simulations. Delayed onset at EGC and WWA, false onset at CGC coupled with significant increase in precipitation rate at LES and ES may result in crop failure, displacement and destruction of infrastructure if no adaptation strategy is put in place.