Water scarcity, insufficient freshwater resources to meet the human and environmental demands of a given area. Water scarcity is inextricably linked to human rights, and sufficient access to safe drinking water is a priority for global development. However, given the challenges of population growth, profligate use, growing pollution, and changes in weather patterns due to global warming, many countries and major cities worldwide, both wealthy and poor, faced increasing water scarcity in the 21st century.
There are two general types of water scarcity: physical and economic. Physical, or absolute, water scarcity is the result of a region’s demand outpacing the limited water resources found there. According to the Food and Agricultural Organization (FAO) of the United Nations, around 1.2 billion people live in areas of physical scarcity; many of these people live in arid or semi-arid regions. Physical water scarcity can be seasonal; an estimated two-thirds of the world’s population lives in areas subject to seasonal water scarcity at least one month of the year. The number of people affected by physical water scarcity is expected to grow as populations increase and as weather patterns become more unpredictable and extreme.
Economic water scarcity is due to a lack of water infrastructure in general or to the poor management of water resources where infrastructure is in place. The FAO estimates that more than 1.6 billion people face economic water shortage. In areas with economic water scarcity, there usually is sufficient water to meet human and environmental needs, but access is limited. Mismanagement or underdevelopment may mean that accessible water is polluted or unsanitary for human consumption. Economic water scarcity can also result from unregulated water use for agriculture or industry, often at the expense of the general population. Finally, major inefficiencies in water use, usually due to the economic undervaluing of water as a finite natural resource, can contribute to water scarcity.