Integrated spatio-temporal and environmental modelling of water scarcity in Saudi Arabia using shared socioeconomic pathways

Saudi Arabia, one of the driest nations globally, faces increasing water scarcity due to rapid population growth, urbanization, industrialization, agricultural expansion, and the impacts of climate change and global warming. This study assesses future water demand, supply, and stress in the Kingdom for the years 2030, 2050, and 2080 by applying three combinations of Shared Socioeconomic Pathways (SSPs) and Representative Concentration Pathways (RCPs): SSP 1 RCP 2.6 (optimistic), SSP 3 RCP 7.0 (business as usual), and SSP 5 RCP 8.5 (pessimistic). The analysis includes baseline water depletion, interannual and seasonal variability, groundwater depletion, and water stress trends. Results demonstrate a clear temporal increase in water demand and stress, accompanied by diminishing water supply across all scenarios, with the optimistic scenario yielding the most favourable outcomes. Surprisingly, by 2080, the pessimistic scenario showed lower water demand, higher water supply, and reduced water stress compared to the business-as-usual model, likely driven by a projected decrease in population and cultivated area by century's end. Although water demand distribution remains relatively stable across time and scenarios, significant changes in water supply and stress patterns emerge. These findings suggest that Saudi Arabia will face escalating water scarcity, highlighting the urgent need for effective adaptation and mitigation strategies by policymakers to avert future water crises.