Tuesday, September 6, 2011

Sky Farming

By 2025, the world’s population will swell from 6.6 billion to 8 billion people. Climate simulations predict sustained drought for the American Midwest and giant swathes of farmland in Africa and Asia. Is mathematician Thomas Malthus’s 200-year-old prediction, that human growth will one day outpace agriculture, finally coming to pass? Advances in farming technology have kept us fed so far, but the planet’s resources are tapped.
The choice is clear—rethink how we grow food, or starve. Environmental scientist Dickson Despommier of Columbia University and other scientists propose a radical solution: Transplant farms into city skyscrapers. These towers would use soil-free hydroponic farming to slash demand for energy (they’ll be powered by a process that converts sewage into electricity) while producing more food. Farming skyward would also free up farmland for trees, which would help remove carbon dioxide from the atmosphere. Even better, vertical farms would grow food near where it would be eaten, thus cutting not only the cost but the emissions of transportation. If you include emissions from the oil burned to cultivate and ship crops and livestock in addition to, yes, methane from farm-animal flatulence, agriculture churns out nearly 14 percent of the world’s greenhouse-gas emissions.
Imagine a cluster of 30-story towers on Governors Island or in Hudson Yards producing fruit, vegetables, and grains while also generating clean energy and purifying wastewater. Roughly 150 such buildings, Despommier estimates, could feed the entire city of New York for a year. Using current green building systems, a vertical farm could be self-sustaining and even produce a net output of clean water and energy.

Despommier began developing the vertical-farming concept years ago (his research can be found at verticalfarm .com), and he has been contacted by scientists and venture capitalists from the Netherlands to Dubai who are interested in establishing a Center for Urban Sustainable Agriculture, either independently or within Columbia. He estimates it could take a working group of agricultural economists, architects, engineers, agronomists, and urban planners five to ten years to figure out how to marry high-tech agricultural practices with the latest sustainable building technology.

You can’t buy vertically grown groceries just yet. Most urban farming efforts have been small-scale experiments run in neighborhood parks. Despommier’s vision is bigger: a $200-million, 30-story tower covering an entire city block, stuffed with enough fruit, vegetables and chickens to feed 50,000 people. “With waste in and food out, a vertical farm would be like a perpetual-motion machine that feeds a lot of people,” he says. Most of the technology already exists, he adds, and with some refining, the project could be up and running quickly if granted 0.25 percent of the subsidies paid to American farmers in the past decade—a piddling $500 million.

What does this have to do with climate change? The professor believes that only by allowing significant portions of the Earth’s farmland to return to forest do we have a real chance of stabilizing climate and weather patterns. Merely reducing energy consumption—the centerpiece of the proposal Al Gore recently presented to Congress—will at best slow global warming. Allowing forests to regrow where crops are now cultivated, he believes, would reduce carbon dioxide in the atmosphere as least as much as more-efficient energy consumption.

There is another reason to develop indoor farming: exploding population growth. By 2050, demographers estimate there will be an additional 3 billion people (a global total of 9.2 billion). If current farming practices are maintained, extra landmass as large as Brazil would have to be cultivated to feed them. Yet nearly all the land that can produce food is already being farmed—even without accounting for the possibility of losing more to rising sea levels and climate change (which could turn arable land into dust bowls).

Depending on the crops being grown, a single vertical farm could allow thousands of farmland acres to be permanently reforested. For the moment, these calculations remain highly speculative, but a real-life example offers a clue: After a strawberry farm in Florida was wiped out by Hurricane Andrew, the owners built a hydroponic farm. By growing strawberries indoors and stacking layers on top of each other, they now produce on one acre of land what used to require 30 acres.

Why build vertical farms in cities? Growing crops in a controlled environment has benefits: no animals to transfer disease through untreated waste; no massive crop failures as a result of weather-related disasters; less likelihood of genetically modified “rogue” strains entering the “natural” plant world. All food could be grown organically, without herbicides, pesticides, or fertilizers, eliminating agricultural runoff. And 80 percent of the world’s population will be living in urban areas by 2050. Cities already have the density and infrastructure needed to support vertical farms, and super-green skyscrapers could supply not just food but energy, creating a truly self-sustaining environment.

Like the Biosphere 2 project in Arizona, a real vertical farm will probably require a utopian philanthropist with deep pockets. In the eighties, Edward Bass spent $200 million of his own money to construct the Biosphere. A smaller and less complex vertical farm would probably cost that much to build today and could be funded by someone from a country where arable land is already in short supply, such as Japan, Iceland, or more likely Dubai. Despommier is convinced the first vertical farm will exist within fifteen years—and the irony is, oil money could very well build it.

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