Overview

• Under a high‑emissions pathway, about 35% of drought‑risk regions are projected to face a first day‑zero drought within roughly 15 years.
• The most exposed areas include the Mediterranean basin, southern Africa, and parts of North America such as California and Texas.
• By century’s end, up to 750 million people could encounter extreme water scarcity, including about 470 million residents of cities.
• The study estimates that around 14% of large reservoirs in Mediterranean countries such as Spain, Greece, Turkey, Algeria and Morocco could run dry during their first day‑zero event.
• Researchers define day‑zero droughts through combined deficits in rainfall, river flows and evaporation alongside unadapted withdrawals, and they urge water savings, reuse, expanded storage and efficiency improvements.