Future water resources and droughts in the Atlas Mountains of Morocco under a high-emission climate scenario

Study Region: Morocco, North Africa. This study examines 36 mountainous basins that supply most of the country’s surface water. Study Focus: This study aims to evaluate the potential impacts of climate change on discharge in Morocco. Two hydrological models, World Wide HYPE and GR4J-CemaNeige, were used in combination with outputs from nine bias-corrected regional climate models. Future discharge was projected under the high-emission RCP8.5 scenario for the mid-century (2040–2060) and late-century (2070–2100). By implementing a state-of-the-art modeling approach on numerous representative sites, the study provides a robust framework for assessing changes in hydrological processes and water availability. New Hydrological Insights for the Region: This research identifies critical changes in snow dynamics, with peak snow storage projected to decrease by over 50 % due to rising temperatures. Consequently, the contribution of snowmelt to discharge will significantly diminish. These snow-related shifts are heading to an average reduction in discharge of −55 % by the late century (2070–2100). This reduction is primarily driven by significant decreases in precipitation (up to −43 %) combined with substantial increases in potential evapotranspiration (up to +38 %). Additionally, hydrological droughts are expected to become more frequent and prolonged, underscoring the urgent need for adaptive water management strategies specifically designed to address basin-specific characteristics. • Severe droughts ahead: Duration and frequency will double under RCP8.5. • Rivers at risk: Projected discharge losses could reach 80 % by 2100. • Increased evaporation: ETP increases up to 38 %, intensifying water scarcity. • Arid zones are the most impacted: Drier basins face longer and more frequent droughts. • Declining snow storage: Peak snow storage is projected to decrease by over 50 %.