Global distribution of physical water scarcity by major river basin, 2011. fao.org

Water scarcity is growing and salinization and pollution of groundwater and degradation of water bodies and water-related ecosystems are rising, the State of the World’s Land and Water Resources for Food and Agriculture (SOLAW) reports. Large inland water bodies are under pressure from a combination of reduced inflows and higher nutrient loading — the excessive build up of nutrients like nitrogen and phosphorus. Many rivers do not reach their natural end points and wetlands are disappearing. In key cereal producing areas around the world, intensive groundwater withdrawals are drawing down aquifer storage and removing the accessible groundwater buffers that rural communities have come to rely on. “Because of the dependence of many key food production systems on groundwater, declining aquifer levels and continued abstraction of non-renewable groundwater present a growing risk to local and global food production,” FAO’s report cautions.

Agricultural Systems At Risk: Human Pressure On Land And Water [pdf]