Sabino Catrilaf, a Mapuche farmer, irrigates his Chilean lettuce field—pouring both water and energy resources into food production. Increasingly, human demands for water and food are straining energy supplies—and vice versa, a water-energy-food nexus of interdependence. (See "In Rotterdam, Shining a Light on the Linked Stresses For Water, Food, and Energy.")
Farmers use huge amounts of electricity to tap underground water sources and pump fluids to their fields. Subsidized by governments, many are using too much power, producing too many emissions, and depleting finite ground water at an unsustainable rate. (See "Growing Food Demand Strains Energy, Water Supplies.")
When crops like corn are used as energy sources, the tight ties within this nexus grow stronger still—and threats to one aspect can quickly cascade to impact the others. (See "Drought Withers U.S. Corn Crop, Heats Debate on Ethanol.")
But other synergies between water and energy may lead to creative, sustainable solutions. Scientists are working to tap the energy that's currently poured down our drains in the form of hot laundry, shower, and dishwasher waste. Some experts estimate that enough energy to power 30 million American homes—about 350 billion kilowatt-hours—is sent down the sewers each year. (See "Waste Wattage: Cities Aim to Flush Heat Energy Out of Sewers.")
Test your knowledge of the nexus by taking this quiz: "What You Don't Know About Food, Water, and Energy"