National Geographic : 2011 Mar
INDUSTRIAL FARMING Almería Province, Spain EDWARD BURTYNSKY On the arid plains of southern Spain, produce is grown under the world's largest array of greenhouses and trucked north. Greenhouses use water and nutrients efficiently and produce all year---tomatoes in winter, for instance. But globally the challenge is grain and meat, not tomatoes. It takes 38 percent of Earth's ice-free surface to feed seven billion people today, and two billion more are expected by 2050.