Physical water scarcity

Physical water scarcity occurs when and where there is not enough water to meet both human demands and those of ecosystems to function effectively. Arid regions frequently suffer from physical water scarcity. It also occurs where water seems abundant but resources are over-committed. This can happen where there is overdevelopment of hydraulic infrastructure, often for irrigation or energy generation. Symptoms of physical water scarcity are severe environmental degradation, declining groundwater and water allocations that favour some groups over others.

The term was first defined in a wide-ranging 2007 study on the use of water in agriculture over the previous 50 years. The study was undertaken by a broad partnership of practitioners, researchers and policymakers, overseen by the International Water Management Institute in Sri Lanka, with the aim of finding out if the world has sufficient water resources to produce food for future populations. The study found that more than 1.2 billion people live in areas of physical water scarcity.

The term economic water scarcity was used by the study to define situations where demand for water is not satisfied because of a lack of investment in water or a lack of human capacity to satisfy demand.