^{These facts are from “When the World’s Wells Run Dry” by Sandra Postel}

^{· Groundwater overpumping may now be the single biggest threat to food production}

^{· It takes about 1,000 tons of water to produce one ton of grain}

^{· Some 40% of the global harvest comes from 17 % of cropland that is irrigated}

^{· 180 million tons (10%) of the global harvest is being produced by depleting water supplies}

^{· Between 1950 and 1995, world irrigated area increased from 100 to 250 million hectares (1 hectare = 10,000 square meters)}

^{· In 1961, China had 110,000 irrigation wells. By the mid 1980s, they had 2.4 million.}

^{· In grain producing regions in China, the water table is dropping 1 to 1.5 meters per year}

^{· In 1961, India was irrigating 100,000 hectares. In 1985 they were irrigating 11.3 million hectares.}