The sedimentation crisis poses significant risks to global water security, potentially affecting over 2 billion people and a quarter of the world's irrigated land. Reservoirs in arid regions are especially at risk, with nearly three-quarters expected to become functionally dead by 2060. In Namibia, over 99% of dams are in danger, while Australia's fragile soils and vegetation clearing exacerbate the problem. The study warns that climate change could accelerate sedimentation rates due to increased rainfall, further straining water supplies for a growing global population.