Now that there are hardly any farmers left to migrate from the cornfields to the city, farms themselves are poised to make the big move. That, at least, is Dickson Despommier's premise in The Vertical Farm: Feeding the World in the 21st Century. The medical ecologist, recently retired from Columbia University's School of Public Health, envisions a utopian future where plastic skyscrapers rise out of "squalid urban blight" to produce bumper crops of high-tech veggies and turn even our filthiest municipalities into "the functional urban equivalent of a natural ecosystem."
Like many purveyors of urban agriculture, Despommier thinks we should be producing our food closer to where we eat it. Don't expect to find him reconnecting with America's agrarian past by shoveling the dung of Williamsburg hipsters onto heirloom kale in some vacant city lot, though. Despommier instead embraces a techno-progressive approach that out-industrializes the Big Ag factory farms that locavores typically loathe. For him, transparent buildings made out of self-cleaning plastic, sterile grow rooms with double-locking doors, and genetically modified plants that can detect and warn against verboten pathogens are the keys to environmental sustainability and healthier food.
According to Despommier, traditional agricultural production requires too much land, too much water, and far too many pesticides, herbicides, and fertilizers. Irrigating farmland consumes 70 percent of our fresh water, he writes, and the runoff that results from this irrigation "is by far the world's most damaging source of pollution." Forsaking synthetic pesticides, herbicides, and fertilizers is one response to this problem, but organic farming produces less food than chemical farming does, and Despommier argues that even chemical farming won't be able to yield enough food for the world as it adds another three billion hungry mouths during the next 40 years. To feed them using current techniques, he asserts, we'd need a land mass the size of Brazil, and in his estimation "that amount of additional arable land simply does not exist."
Of course, we could deploy our arable land more efficiently, planting crops for human beings instead of livestock and ethanol. But Despommier has another solution in mind: controlled indoor agriculture, verticalized and situated in our cities.
In Despommier's vertical farms, vegetables and fruits would be grown hydroponically. There would be lettuce on one floor, green beans on another, peppers in the penthouse. Hydroponics and a related technology called aeroponics use 70 percent to 95 percent less water than conventional farming does. Growing crops indoors allows for year-round production and guards against weather-related crop failure. Building vertical farms in the cities, where most food is ultimately consumed, would conserve fossil fuels needed for transport, curtail spoilage, and allow for the reforestation of land currently devoted to agriculture, thus offsetting carbon emissions and increasing biodiversity.
Despommier conceived of vertical farms in 1999, and with the help of his graduate students at Columbia he has been refining the idea ever since. At his website (verticalfarm.com), architectural renderings submitted by fellow visionaries tend to show massive, futuristic structures, but in his book he describes plans for a prototype of more modest dimensions: It would be five stories tall, with a footprint equal to one-eighth of a city block. In ideal locations, he believes, sunlight could provide all the energy needed to grow crops, and photovoltaics could power any necessary electrical equipment. Buildings would be constructed from aluminum framing and large panels of a lightweight, transparent plastic called ETFE. Pests and pathogens would be excluded via "filtered air supplies, secure locks, and workers who must change their clothes before entering." Recycled municipal wastewater would irrigate the crops. Solid wastes and inedible plant matter could generate additional power if needed. "If New York's 8 million citizens decided to pool their fecal resource and generate electricity by incinerating it, they could realize an astounding 900 million kilowatts of electricity per year," Despommier writes.
Alas, not everyone places such faith in the burning shit of Manhattan. While Despommier's ideas have attracted substantial attention, they have also generated substantial skepticism. Can sunlight alone provide enough energy to grow plants on multiple floors, even if the building is highly transparent and situated and shaped to take maximum advantage of the sun's progression across the sky? If LEDs or other forms of artificial lighting typically used in hydroponic operations are necessary, how much will this add to the cost? Can massive urban greenhouses function without pesticides when marijuana growers with modest hydroponic setups seem to spend most of their waking hours battling fungus gnats? Is it prudent to build vertical farms in the middle of the city, where even down-market real estate goes for a premium compared to Kansas farmland, given that food miles have relatively little impact on greenhouse gas emissions? Can vertical farm revenues match the costs of erecting a plastic skyscraper, or even cover the rent for commercial real estate in Manhattan?
Despite such questions, Despommier's ideas already have inspired entrepreneurs around the globe. So far those pursuing projects under the "vertical farm" rubric have yet to embark on any projects as wide in scope as Despommier imagines. Instead they are setting up operations in urban warehouses or other already existing buildings. Their verticality tends to be limited to stacked hydroponic trays, not multiple floors. They are using artificial light sources as well as the sun.
In Surrey, British Columbia, a company called TerraSphere runs a facility that has started selling spinach and lettuce to a local chain of natural food stores called Choices Market. A British zoo uses equipment supplied by a company called Valcent to produce greens for its animals. And in Chicago, a developer named John Edel is turning a former meatpacking plant into a vertical farm that will grow organic produce and serve as a space for small food-processing businesses and a brewery.
On all four stories, the facility, which Edel has dubbed The Plant, will use aquaponics: Fish will be raised in tanks, their waste will fertilize hydroponically grown produce, and the produce will filter water for the fish. Edel is also building an anaerobic digester that will use waste materials generated by The Plant to power its heat and power systems. Its old-school industrial brick facade may lack the stunning sci-fi pop of some vertical farm designs, but inside the building an innovative new approach to agriculture is taking root.