Change in Climate Indices Using Bias-Adjusted CMIP5 Models: The Case Study of the Fatick Region, Senegal

Abstract

This study analyses change in rainfall and temperature indices by 2035 and 2050 in Senegal, with a focus on the Fatick region. These parameters are crucial for understanding the impacts of anthropogenic climate change on some vital socio-economic sectors such as agriculture and water resources in this region. To this end, a multi model ensemble mean of 21 bias-adjusted global climate models participating in CMIP5 has been used. We considered two Representative Concentration Pathways (RCP4.5 and RCP8.5). The results indicate an increase of 0.7˚C for maximum and minimum temperature by 2035 compared to the reference period (1976 -2005). By 2050, an increase of 1.4˚C (2˚C) is projected for RCP4.5 (RCP8.5). These increases in temperature are statistically significant at the 90% confidence level. Conversely, the mean rainy season length decreases from 95 to 85 days by 2035 and less than 80 days by 2050. These decreases in rainy season length are mainly due to a delayed rainy season onset by 2035 and 2050, with the ensemble mean projecting an onset in the second half of July by 2050 instead of around the middle of June. The changes in both the onset and the length of the rainy season are significant at the 90% confidence level. Our results show a slight decrease in seasonal cumulated total rainfall by 2035 and 2050. However, we note a slight increase in seasonal cumulated extreme rainfall.