Water Scarcity
Overview
Water scarcity refers to a state in which the quantity and quality of freshwater needed for human domestic, industrial, and agricultural activity cannot be sufficiently secured. About 97.5% of the water on Earth is seawater, and freshwater accounts for only 2.5%; most of that exists as glaciers and deep groundwater, so the water that is actually readily usable amounts to less than 1% of the total. As population growth, climate change, water pollution, and excessive withdrawal converge, water scarcity has become one of the most serious environmental and economic threats of the 21st century.
Main Content
Definition and Distinctions
Water scarcity is broadly divided into two types. Physical scarcity is the case where the water resources of a given region cannot keep up with demand, while economic scarcity is the case where water exists but the infrastructure, technology, and capital to withdraw, purify, and supply it are lacking. The United Nations classifies a region as under "water stress" when annual renewable freshwater per capita falls below 1,700 m³, as experiencing "water scarcity" below 1,000 m³, and as experiencing "absolute water scarcity" below 500 m³. This indicator, proposed by the Swedish hydrologist Malin Falkenmark, is used today as the standard for international comparison.
Main Causes
- Population growth and urbanization: As the world population surpassed 8 billion, demand for domestic water surged, and concentration in large cities has increased the withdrawal burden on specific river basins.
- Climate change: As the variability of precipitation patterns has grown and the frequency and intensity of droughts have increased, stable supply has become more difficult. The shrinkage of mountain glaciers also affects the flow of major Asian rivers.
- Excessive agricultural water use: About 70% of global freshwater withdrawals are used for agriculture, and inefficient irrigation creates enormous losses.
- Water pollution: Industrial wastewater, agricultural chemicals, and domestic sewage are deepening "qualitative water scarcity" by reducing the water available for use.
- Groundwater over-extraction: This causes aquifer depletion, land subsidence, and saltwater intrusion in coastal areas.
Regional Status
The Middle East and North Africa (MENA) region has the highest water stress in the world, and the Gulf states rely on seawater desalination for most of their freshwater. Sub-Saharan Africa and South Asia show pronounced infrastructure-related water scarcity, while northwestern India and Pakistan face severe groundwater depletion. In Central Asia, the shrinkage of the Aral Sea remains the most representative case. Canada, Brazil, and Russia, by contrast, are relatively abundant, but with wide disparities between regions.
Ripple Effects
Water scarcity is directly tied to food security. If irrigated agriculture contracts, grain production and prices waver, which can lead to political instability. A lack of safe drinking water causes the spread of waterborne diseases and rising child mortality. In addition, the potential for conflict over shared rivers between countries (such as the Nile, the Mekong, and the Tigris–Euphrates) is growing, and the problem of securing cooling water for hydropower and for thermal and nuclear power generation is also intertwined with energy security. On the ecological side, the loss of wetlands and freshwater biodiversity is accelerating.
Response Measures
Representative solutions include seawater desalination, the supply of reclaimed wastewater, irrigation efficiency measures such as drip irrigation, leak management, a shift in consumption based on water footprints, tiered water pricing and the alignment of water prices with reality, and the introduction of smart meters and remote meter reading. Internationally, UN Sustainable Development Goal (SDG) 6, "water and sanitation for all," is the core framework, and cross-border basin cooperation bodies and data-sharing systems are also expanding.
Latest Trends
With the 2023 UN Water Conference held for the first time in 46 years, water rose to the forefront of the international agenda, and countries have since announced national water roadmaps one after another. In 2024–2025, record droughts recurred along the Mediterranean coast (Catalonia in Spain, Sicily in Italy), in the Brazilian Amazon, in the western United States, and in the Horn of Africa, prompting emergency water supply measures. Technologically, improvements in reverse-osmosis membrane efficiency and energy recovery devices have lowered desalination costs, and small solar-powered desalination facilities are being distributed in developing countries. Atmospheric water generators (AWGs) that capture moisture from the air, AI-based detection of leaks in water supply networks, and basin management using digital twins are also spreading rapidly. Meanwhile, as water demand from AI data centers and semiconductor plants surges, the "water–energy–data nexus" has emerged as a new policy issue, and competition to secure the freshwater needed for green hydrogen production has also begun in earnest. At the corporate level, adoption of CDP water reporting and Science-Based Targets for Nature (SBTN) is increasing, and as of 2025 more than half of major global companies include water risk in their financial reporting.
Related Topics
- [[Climate Change]]
- [[Drought]]
- [[Seawater Desalination]]
- [[Water Resource Management]]
- [[Food Security]]
- [[Sustainable Development Goals]]
- [[Groundwater]]