Predicting Standardized Precipitation Evapotranspiration Index for FadaN’Gourma by 2050 Using CMPI-6 Outputs under SSPs Scenarios

Extreme weather events, such as floods and droughts, are expected to rise significantlyworldwide as a result of climate change. Investigating future drought patterns is therefore a key approach for elaborating anticipatory water resources management responses to climate change. In this paper, future meteorological drought conditions are investigated based on the SPEI (Standardised Precipitation Evapotranspiration Index). This study makes use of observed and projected data. The simulated data were retrieved from the CMIP6 (Coupled Model Intercomparison Project Phase 6) over the period 2025-2050, and the Delta change method was adopted to remove the bias in the dataset. Then SPEI at various scales has been estimated under four future scenarios (SSP1-2.6, SSP2-4.5, SSP3-7.0 and SSP5-8.5). The trend analysis of the projected SPEI was performed at p< 0.05 using the MMK (Modified Mann-Kendall) test in order to detect the statistically significant trend of the drought against the null hypothesis of no trend. Results show large variability in the magnitude of drought in the past and future. Based on SPEI at 24 months accumulation, the result shows that under SSP1-2.6, the basin will experience a wet period during the first decade (SPEI = 0.60), the second decade will be dry (SPEI24 = -0.43). The remaining years will be also dry (SPEI = -0.34). Under SSP2-4.5, SSP3-7.0 and SSP5-8.5 scenarios, the district will experience a wet period during the first two decades with SPEI ranging from 0.38 to 0.59. This wet period will be followed by a dry period under these scenarios ranging from -0.14 to -0.06. Overall, under SSPs scenarios, two main periods characterized by a rainfall recovery spanning from followed by a moderately prolonged drought are identified within the study area. The findings of this study may provide valuable information for developing proactive measures to reduce water insecurity in FadaN’Gourma through effective drought mitigation.