Sguigaa et al. (2026) Retrospective Analysis and Future Projections of Bioclimatic Indices Under Climate Change: The Case of Azilal Province, Morocco

Identification

• Journal: BIO Web of Conferences
• Year: 2026
• Date: 2026-01-01
• Authors: Ayoub Sguigaa, Saïd Moukrim, Saïd Lahssini, Abdellatif Khattabi
• DOI: 10.1051/bioconf/202621503004

Research Groups

• National School of Forest Engineers (ENFI), Salé, Morocco
• Mohammed V University in Rabat (UM5R), Rabat, Morocco

Short Summary

This study analyzes historical (1983-2016) and projected (2015-2100) bioclimatic changes, water balance, and thermal extremes in Azilal Province, Morocco, under CMIP6 SSP2-4.5 and SSP5-8.5 scenarios, revealing significant warming, increasing aridity, and an expansion of "Dry/DTR↑" bioclimatic regimes.

Objective

• To quantify past trends (1983-2016) and future projections (2015-2100) of temperature, precipitation, dryness, drought, and the evolution of bioclimatic regimes in Azilal Province, Morocco, using historical data and downscaled CMIP6 projections under SSP2-4.5 and SSP5-8.5 scenarios.

Study Configuration

• Spatial Scale: Azilal Province, High Atlas, Morocco.
• Temporal Scale: Historical analysis (1983-2016); Future projections (2015-2100) with operational horizons: near term (2021-2040), mid term (2041-2060), and long term (2081-2100).

Methodology and Data

• Models used: Three CMIP6 models (CNRM-CM6-1, GFDL-ESM4, MRI-ESM2-0) downscaled using NEX-GDDP-CMIP6.
• Data sources:
  • Historical: CHIRPS v2 (rainfall), CHIRTS (daily temperature Tmax/Tmin) for 1983-2016.
  • Future: Downscaled CMIP6 projections under SSP2-4.5 and SSP5-8.5 scenarios.
  • Climate indices calculated: Reference evapotranspiration (ET0) using Hargreaves-Samani, Climatic Moisture Index (CMI), UNEP Aridity Index (AI), Gaussen criterion for dry season length, Standardized Precipitation Index (SPI), Standardized Precipitation Evapotranspiration Index (SPEI), and ETCCDI thermal extremes.
  • Statistical methods: Mann-Kendall test for trends, Theil-Sen estimator for slopes, k-means clustering for bioclimatic regimes.

Main Results

• Historical Warming (1983-2016): Mean annual temperature increased by +1 °C, with Tmax increasing faster (+0.44 °C per decade) than Tmin (+0.30 °C per decade). Hot extremes significantly increased: days > 35 °C (+13.8% per decade) and days > 40 °C (+41.6% per decade).
• Historical Precipitation (1983-2016): Annual precipitation (average 520 mm per year) showed high variability but no significant trend.
• Future Temperature Projections (2015-2100): Mean annual temperature is projected to increase by +3 to +4 °C under SSP2-4.5 and +5 to +7 °C under SSP5-8.5 by 2100 (relative to 1995-2014).
• Future Precipitation Projections (2015-2100): Median annual precipitation is projected to decrease by 20-30% by 2100 under SSP5-8.5, with deficits becoming more frequent after 2040 (SSP2-4.5) or earlier (SSP5-8.5).
• Aridification and Water Balance: Climatic Moisture Index (CMI) is projected to decrease further, reaching -1.35 to -1.50 m per year under SSP2-4.5 and -1.55 to -1.70 m per year under SSP5-8.5 by 2100. SPEI-12 shows a pronounced negative drift, indicating more persistent deficits, particularly under SSP5-8.5.
• Dry Season Length: Projected to increase from approximately six months to 11-12 months per year by the end of the century under both scenarios.
• Bioclimatic Regimes: Two main regimes identified: "Wet/DTR↓" and "Dry/DTR↑". The "Dry/DTR↑" regime (characterized by lower precipitation of wettest month and higher mean diurnal temperature range) is projected to expand to 50-60% of the province by 2100 under SSP5-8.5.
• Combined Signal: The region faces rising exposure to heat and water scarcity, with implications for land, forest, and water resource management.

Contributions

• This study provides a unique, scenario-consistent approach by jointly combining bioclimatic regimes, hydroclimatic water balance diagnostics, and indicators of extreme heat and drought for the Azilal Province, which was previously understudied in this integrated manner.
• It establishes a province-scale baseline for climate trends, extremes, and water balance, offering objective insights for territorial planning and adaptation strategies in a climate change hotspot.
• The identification and projected expansion of distinct bioclimatic regimes ("Wet/DTR↓" and "Dry/DTR↑") offer a practical management key for differentiated silvicultural paths and water resource planning.

Funding

• [No explicit funding section or acknowledgment found in the provided text.]

Citation

@article{Sguigaa2026Retrospective,
  author = {Sguigaa, Ayoub and Moukrim, Saïd and Lahssini, Saïd and Khattabi, Abdellatif},
  title = {Retrospective Analysis and Future Projections of Bioclimatic Indices Under Climate Change: The Case of Azilal Province, Morocco},
  journal = {BIO Web of Conferences},
  year = {2026},
  doi = {10.1051/bioconf/202621503004},
  url = {https://doi.org/10.1051/bioconf/202621503004}
}