Global water security threatened by rising inequality.
Abstract: The global water-scarcity crisis is fundamentally driven by inequality, yet most forecasts overlook equity as a causal factor, leading to misdiagnosed problems and ineffective solutions. Here we develop a machine-learning-based global water-use forecasting model to project future water use and scarcity under distinct Shared Socioeconomic Pathways representing alternative development trajectories. Drawing on decades of historical data on human adaptation and resource use, the model predicts that by 2050, 6.5 billion people—equivalent to 65.5% of the global population—will face severe water scarcity under a high-challenge fragmentation scenario. By 2100, this figure is projected to rise to 8.0 billion, or 63% of the global population, far exceeding most previous estimates. Our analysis shows that a high inequality pathway directly amplifies water-scarcity risk. Critically, a technology-driven pathway improves aggregate water-use efficiency but concurrently deepens social and spatial inequalities. These findings underscore the need to move beyond purely technological fixes towards integrated, equitable water management, demonstrating that greater justice is inseparable from greater water security.
Sheng, J., Cheng, Q. & Yang, H. Global water security threatened by rising inequality. Nat. Geosci. (2026). https://doi.org/10.1038/s41561-025-01905-y
