Compound hot–dry extremes in Senegal: trends and time of emergence in a warming world

Abstract This study examines the duration, intensity, and frequency of compound hot and dry extremes (CHDEs) in Senegal, together with their time of emergence (ToE), using daily temperature and precipitation from ten NASA Earth Exchange Global Daily Downscaled Projections–Coupled Model Intercomparison Project Phase 6 (NEX-GDDP-CMIP6) models under three Shared Socioeconomic Pathways (SSP1-2.6, SSP2-4.5, and SSP5-8.5). Observations from the Climate Hazards Group Infrared Temperature with Stations dataset for temperature and the Climate Hazards Group InfraRed Precipitation with Stations dataset for precipitation are used for historical evaluation (1985–2014). During this period, CHDE duration reaches up to 4 d in northern Senegal, with maximum intensities of 44 °C–46 °C and frequencies of 3–4 events per year. A slight upward trend in duration is observed, consistent with accelerated warming since the 1980s. The multi-model ensemble reproduces spatial and temporal CHDE patterns reasonably well, though duration and intensity are underestimated in northern Senegal and frequency is overestimated in the northwest coastal zone. Projections indicate substantial increases across all scenarios, with the largest changes under SSP5-8.5, where duration may lengthen by over six days, intensity may exceed historical baseline by 8 °C, and frequency may reach 10–14 events by 2100. The ToE analysis shows that under SSP5-8.5, CHDE intensity and frequency may emerge from historical variability as early as 2025, much earlier than under SSP1-2.6. The early and widespread emergence of CHDEs, particularly in the northern and coastal regions, emphasises the urgent need for robust adaptation strategies and rapid emission reductions. These findings offer crucial insights for climate risk management and can inform national planning efforts to mitigate the escalating threats of compound climate extremes.