Analysis of current and future climate variability and drought recurrence in Benin, West Africa

Abstract

West Africa's climate is complex and highly variable. This study investigates the climatic patterns of Benin during the current period (1980–2014) and projected future periods (2050, 2099). Three Shared Socioeconomic Pathways (SSPs) from the Coupled Model Inter-comparison Project (CMIP6) models were used: the optimistic (SSP126), medium (SSP245), and pessimistic (SSP585) scenarios. Model performance was evaluated using the Kling–Gupta efficiency (KGE), and climate trends were analyzed using the Mann–Kendall test. Extreme precipitation indices – R20mm, RX1day, RX5days, and CDD – were employed to characterize precipitation extremes, and Standardized Precipitation Index (SPI) for drought recurrence. Model temperatures, very consistent with observations (KGE > 0.7), revealed an upward trend over the current period (0.17 °C/decade) and an amplification toward the end of the century (0.44 °C/decade, SSP585). Precipitation also showed an upward trend during the current period (4.18 mm/year), but this could be reversed in certain areas/periods or scenarios. Furthermore, the current period is dominated by the wet years vs. dry years at the end of the century (59.56% for SPI 12 months using SSP245). The current climate is characterized by upward trends for R20mm, RX1day, and RX5days. SSP245 shows that it will be more intense at the end of the century. It is therefore necessary to determine and highlight the impacts of climate change on ecosystems.