Water management is a central responsibility of civil society. Major questions persist regarding practice, policy, and the underlying evidence and methods to inform both. This essay addresses local versus global. When, and to what extent, should a global viewpoint replace, or work in tandem with, enduring localized perspectives?

Although water problems have been traditionally perceived, understood, and acted on locally, recent progress in Earth-system simulation, remote sensing, and analysis of water governance is producing new perspectives on fresh water. The advances reveal previously unrecognized global forces at work driving local-scale problems. The stage is reset for water research and policy-making.