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Agriculture faces a conundrum: populations needing food are increasing and the necessary land and water resources to produce crops are not. What to do?
The perplexing situation was addressed recently in an article in the November Scientific American, titled, “Growing Skyscrapers: The Rise of Vertical Farms.” Author Dickson Despommier says an insufficient supply of arable land is available to feed a projected 9.5 million population by 2050. Agricultural practices causing environmental harm contribute to the problem.
His solution is to grow food indoors in glass high-rises; he figures that a 30-story structure located on one square block could be as agriculturally productive as 2,400 outdoor acres, with less spoilage. Crops could be grown year-round on these vertical farms under rigorously controlled conditions.
He is proposing an agricultural revolution with an urban twist: high-rise vertical farms would be located in urban areas on now vacant lots and multi-story greenhouses constructed on rooftops. Food would be grown using non-mechanized farming techniques and relying on recycled urban wastewater in areas with the greatest demand, thus reducing transportation costs. This means less fossil fuels consumed and less emissions. Urban life would become more sustainable.
Techniques for growing crops in-doors — drip irrigation, aeroponics and hydroponics— have been successfully applied throughout the world. Despommier singles out for special notice the 318-acre Eurofresh Farms located in Arizona that produces bountiful and varied crops 12 months a year.
He mentions the Southwest with its abundant sunshine as being especially hospitable to vertical farming. He would modify his structures in the region to two or three stories, 50 to 100 yards wide and miles long to maximize natural sunlight for growing and photovoltaics for power.
Despommier also describes the paths best not to take. He says that intensive, highly mechanized industrial farming capable of producing a greater yield of genetically-modified crops fertilized by agrochemicals is not the answer. Nor is the further deforestation of land to produce farmland. Both have severe environmental consequences.
Despommier summarizes: “Vertical farming could revolutionize how we feed ourselves and the rising population to come.”
For another, more here-and-now perspective of Arizona agriculture and its future water needs see above sidebar. It notes a recent CAST issue paper (Council for Agricultural Science and Technology) titled “Water, People, and the Future: Water Availability for Agriculture in the United States.”