Projected Changes in Temperature and Precipitation over the Imam Turki bin Abdullah Royal Reserve using CMIP6 Global Climate Models

الملخص

Understanding future climate change is essential for the sustainable management of protected dryland ecosystems. This study assessed projected changes in maximum temperature (Tmax), minimum temperature (Tmin), and annual precipitation across the Imam Turki bin Abdullah (ITBA) Royal Reserve, Saudi Arabia, using the Coupled Model Intercomparison Project Phase 6 (CMIP6) multi-model ensemble under two Shared Socioeconomic Pathways: SSP2-4.5 and SSP5-8.5. Climate projections were analyzed for five representative stations (Al-Jouf, Gassim, Rafha, Hail, and Qaisumah) for the period 2015–2100, with changes also evaluated relative to the historical baseline (1985–2014). Results indicate that temperature is the most robust climate change signal across the ITBA reserve. Under SSP2-4.5, annual Tmax is projected to increase by approximately 2.4–2.6 °C by 2100, while Tmin rises by about 2.8–2.9 °C. Under SSP5-8.5, warming intensifies substantially, with Tmax increasing by 5.7–6.4 °C and Tmin by 6.8–7.2 °C. Tmin increases exceed those of Tmax under both scenarios, indicating a progressive reduction in diurnal temperature range (DTR) and increasing nighttime heat stress. Warming is spatially coherent across all stations, although northern and interior locations generally exhibit slightly stronger increases than southern stations. In contrast, annual precipitation projections show no statistically robust long-term increasing or decreasing trends under either scenario. Projected anomalies remain small, spatially mixed, and highly uncertain, reflecting the dominant influence of natural variability. However, stable precipitation totals do not imply hydroclimatic stability, as rising temperatures are likely to increase evapotranspiration and intensify aridity, drought risk, and water-resource stress. Overall, the findings demonstrate that the reserve is highly vulnerable to future warming, particularly under SSP5-8.5. The results highlight the need for proactive adaptation strategies focused on heat-risk management, ecosystem resilience, sustainable water planning, and climate-resilient infrastructure, while also emphasizing the benefits of emissions mitigation in reducing long-term regional climate risks