City farming—pigs in the sky?
By Dennis T. Avery
Green visionary, Dixon Despommier, of Columbia University has proposed growing our food in city high-rises, to cut food transport energy use. The bad news is that city farming would be impossibly expensive—as it always has been. The good news: the high-rise farms will never be built.
Another project, the Sky-farm Project was proposed in 2007, as a 58-floor skyscraper that would produce as much food as an 800-acre farm! But the U.S. farms more than 400 million acres of land—equal to 500,000 skyscraper farms! Those sky-towers would cost billions.
Cropland in Iowa costs an average of $6,000 per acre or about $5 million for an 800 acre farm. An acre or so of usable land In Manhattan might cost about the same $5 million, but construction costs would be enormous.
Each floor of each high-rise would have to support either water-soaked soil or the water for hydroponic production. Ten thousand cubic feet of water per floor would weigh 620,000 pounds. Two hundred people plus their office furniture might weigh only 40,000 pounds.
Replacing sunlight with "grow lights" would take an enormous amount of electricity. Bruce Bugbee, a crop physiologist at Utah State says "We're talking gigawatts of power, just huge amounts of power [to grow crops indoors] compared to free sunlight outside." With glass walls, the winter heating would be costly too.
What about city taxes. What about higher labor costs—or would the city folks volunteer to work free?
The proposed Sky-Farm was to produce fruit, vegetables, pigs and chickens. However, you couldn't grow enough feed in greenhouse conditions to support more than a few pigs or chickens, so you'd have to import most of their feed. Think about four pounds of grain for each pound of pork you harvest. Would it really be less expensive to ship millions of tons of grain into downtown New York than to truck in some pork chops?
I wonder how New Yorkers would feel about having mid-town slaughterhouses. Would there be the irony of trucking in grain to raise chickens and hogs in mid-town, trucking the creatures out of town to be slaughtered and processed, then trucking the meat back into town—all to save fuel?
The real irony is that transportation takes only about 3 percent of the energy used in providing our food. Diesel trains and ships are marvelously energy-efficient. Even a well-laden diesel truck doesn't use much more fuel than four autos.
Be thankful the farmers themselves have better alternatives. Computer-controlled center-pivot irrigation is one of the solutions, using half as much water and half as much electricity for pumping—and paying back its costs in five years.
No-till farming cuts soil erosion by up to 95 percent, and doubles the soil moisture in the fields. Thus we could now safely farm the 36 million acres of the Conservation Reserve, which currently produces only a few pheasants for hunters.
U.S. corn yields have increased more than five-fold in the past 80 years, and these higher yields have cut land costs per bushel of food produced. The seed industry is now promising drought-tolerant crops in the coming years, achieved through the low-cost route of biotechnology.
If New York consumers don't think they like biotech, wait until somebody starts building 300 downtown skyscrapers to further congest their narrow streets with huge grain trucks and trailerloads of pigs and chickens headed for slaughter.
Dennis T. Avery, a senior fellow for the Hudson Institute in Washington, DC, is an environmental economist. He was formerly a senior analyst for the Department of State. He is co-author, with S. Fred Singer, of Unstoppable Global Warming Every 1,500Years, Readers may write him at PO Box 202, Churchville, VA 24421 or email to email@example.com