Résumé
ABSTRACT Water resources are becoming increasingly scarce in the Mediterranean Basin due to climate change. Through a systematic review of 262 catchment‐based Mediterranean studies, we provide improved and detailed indications that runoff is projected to decrease by 19%, with increasing severity towards the end of the century and with increasing emission scenarios (up to −39%). We also show negative consequences for other water resources (soil moisture, aquifer recharge, irrigation demand), hydrological extremes (low flows), and water and soil quality (nutrient concentration, soil salinity, soil erosion), with negative impacts on rainfed and irrigated agriculture in the Mediterranean Basin. To protect water security, climate change adaptation aiming at more efficient water use and water retention in soils will be needed. While these adaptation measures have the potential to reverse the impacts of climate change, they may reduce downstream water availability and may be insufficient under extreme climate conditions.