Retrospective Analysis and Future Projections of Bioclimatic Indices Under Climate Change: The Case of Azilal Province, Morocco

We examine the bioclimatic changes, water balance and thermal extremes in Azilal Province, Morocco using a combination of historical daily temperature and precipitation records (1983-2016) and downscaled climate model intercomparison projections (CMTP6) (2015-2100) in the context of SSP2-4.5 and SSP5-8.5. Over the period 1983-2016, mean annual temperature increases by +1 °C (faster for Tmax (+0.44 °C decade −1 ) than for Tmin (+0.30 °C decade −1 )). Annual precipitation is highly variable and does not show any significant trend, yet the future trend projected is a median 20-30% decrease by 2100 for SSP5-8.5. Moisture Diagnostics show a trend of increasing aridity CMI & SPEI show a strengthening climatic water deficit CMI < -1.5m year −1 by 2100 for SSP5-8.5. Heat extremes increase in strength (days > 35 °C +13.8% per decade) and there is an increase in drought frequency in projections mainly due to increasing evaporative demand. A clustering based on the regimes "Wet/DTR↓" and "Dry/DTR↑" is identified with the regime of "Dry/DTR↑" increasing to 50-60% f the province by 2100 under SSP5-8.5. The combined signal brings up the issue of rising exposure to heat and water scarcity.