Urban farming has always been a slightly quixotic endeavor. From the small animal farm that was perched on the roof of the Upper West Side’s Ansonia apartment building in the early 1900s (fresh eggs delivered by bellhop!) to community gardens threatened by real-estate development, the dream of preserving a little of the country in the city is a utopian one. But nobody has ever dreamed as big as Dr. Dickson Despommier, a professor of environmental sciences and microbiology at Columbia University, who believes that “vertical farm” skyscrapers could help fight global warming.

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 six 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.

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.

1. The Solar Panel
Most of the vertical farm’s energy is supplied by the pellet power system (see over). This solar panel rotates to follow the sun and would drive the interior cooling system, which is used most when the sun’s heat is greatest.

2. The Wind Spire
An alternative (or a complement) to solar power, conceived by an engineering professor at Cleveland State University. Conventional windmills are too large for cities; the wind spire uses small blades to turn air upward, like a screw.

3. The Glass Panels
A clear coating of titanium oxide collects pollutants and prevents rain from beading; the rain slides down the glass, maximizing light and cleaning the pollutants. Troughs collect runoff for filtration.

4. The Control Room
The vertical-farm environment is regulated from here, allowing for year-round, 24-hour crop cultivation.

5. The Architecture
Inspired by the Capitol Records building in Hollywood. Circular design uses space most efficiently and allows maximum light into the center. Modular floors stack like poker chips for flexibility.

6. The Crops
The vertical farm could grow fruits, vegetables, grains, and even fish, poultry, and pigs. Enough, Despommier estimates, to feed 50,000 people annually.

The vertical farm doesn’t just grow crops indoors; it also generates its own power from waste and cleans up sewage water.

1. The Evapotranspiration Recovery System
Nestled inside the ceiling of each floor, its pipes collect moisture, which can be bottled and sold.

2. The Pipes
Work much like a cold bottle of Coke that “sweats” on a hot day: Super-cool fluid attracts plant water vapors, which are then collected as they drip off (similar systems are in use on a small scale). Despommier estimates that one vertical farm could capture 60 million gallons of water a year.

3. Black-Water Treatment System
Wastewater taken from the city’s sewage system is treated through a series of filters, then sterilized, yielding gray water—which is not drinkable but can be used for irrigation. (Currently, the city throws 1.4 billion gallons of treated wastewater into the rivers each day.) The Solaire building in Battery Park City already uses a system like this.

4. The Crop Picker
Monitors fruits and vegetables with an electronic eye. Current technology, called a Reflectometer, uses color detection to test ripeness.

5. The Field
Maximization of space is critical, so in this rendering there are two layers of crops (and some hanging tomatoes). If small crops are planted, there might be up to ten layers per floor.

6. The Pool
Runoff from irrigation is collected here and piped to a filtration system.

7. The Feeder
Like an ink-jet printer, this dual-purpose mechanism directs programmed amounts of water and light to individual crops.

8. The Pellet Power System
Another source of power for the vertical farm, it turns nonedible plant matter (like corn husks, for example) into fuel. Could also process waste from New York’s 18,000 restaurants.

9 to 11. The Pellets
Plant waste is processed into powder (9), then condensed into clean-burning fuel pellets (10), which become steam power (11). At least 60 pellet mills in North America already produce more than 600,000 tons of fuel annually, and a 3,400-square-foot house in Idaho uses pellets to generate its own electricity.

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Could vertical farming be the future?

Rice on the seventh floor. Wheat on the twelfth. And enough food within an 18-story tower to feed a small city of 50,000.

Vertical farms, where staple crops could be grown in environmentally friendly skyscrapers, exist today only in futuristic designs and on optimistic Web sites. Despite concerns over sky-high costs, however, an environmental health expert in New York is convinced the world has the know-how to make the concept a reality — and the imperative to do so quickly.

With a raft of studies suggesting farmers will be hard-pressed to feed the extra 3 billion people swelling the world’s ranks by the year 2050, Columbia University professor Dickson Despommier believes a new model of agriculture is vital to avoid an impending catastrophe.

“The reason why we need vertical farming is that horizontal farming is failing,” he said. If current practices don’t change by mid-century, he points outs, an area bigger than Brazil would need to become farmland just to keep pace with the demand.

Working the soil has always been an uncertain venture, and Despommier argues that the price of crop failure is growing ever steeper as the global population mushrooms. “The world,” he said, “is running out of resources faster than what it can replace.”

Critics like Bruce Bugbee, a professor of crop physiology at Utah State University in Logan, see improvements in how future farmlands are managed as more practical and cost-effective. To Despommier, though, the world already has the need and the technology to dramatically improve yields and reliability by adjusting its point of view: from out to up.

The Columbia researcher said his interest in vertical farming is an extension of his long-standing work on disease transmission among humans. Among the laundry list of benefits he cites, Despommier believes vertical farming could help break the transmission cycle of diseases in traditional agricultural settings. But it’s the potential to help solve impending food shortages that really excites him.

A recent exercise conducted by students in his medical ecology class found that a self-sustaining vertical farm able to feed 50,000 people could “fit comfortably within a city block,” rising perhaps 18 stories. With adequate funding, a smaller prototype could be up and running in seven to 10 years, he predicts. Eventually, full-scale versions could be a new feature of city skylines, climbing as high as 30 stories and filled with automated feeders, monitoring devices and harvesting equipment. And, of course, they would feature crops such as wheat, rice, sugar beets and leafy greens grown in mineral nutrient solutions or without any solid substrates at all.

These hydroponic and aeroponic growing techniques, respectively, have benefited from NASA’s strong interest because any long-term venture to the moon or beyond would require the use of self-contained and resource-limited growth chambers. Despommier concedes that current practices must be improved and systems put in place to quickly identify and quarantine plants stricken with pests or disease. “No pun intended, but the bugs need to be worked out of this thing,” he said.

He insists, though, that money is the last major obstacle. To his critics, that hurdle has tripped up past entrepreneurs and may yet be insurmountable. “I can’t be very optimistic about this study,” said Utah State’s Bugbee. “None of this is very new. But it doesn’t mean the whole concept is without merit. It just means the claims are greatly exaggerated.”

Bugbee’s chief objection is the exorbitant power requirement for such a vertical structure.  Plants on the lower floors would require artificial light year-round or expensive mechanical systems to get more light to them. And during a typical winter in northern U.S. cities, he said, average sunlight is only 5 percent to 10 percent of peak summer levels due to sapped intensity and shorter days.

“November, December, January and February are really dark,” Bugbee said. “Plants aren’t limited by the temperature, they’re limited by the light.” High-pressure sodium lights may be a reasonable stand-in for sunlight to maintain plant growth,  he said, but the electric bill is enormous. “Boy have a lot of people gone bankrupt trying hydroponic greenhouses for that reason.”

Nevertheless,  greenhouses such as Arizona’s 265-acre Eurofresh Farms are thriving with their hydroponic tomatoes and seedless cucumbers. Gene Giacomelli, Director of the Controlled Environment Agriculture Program at the University of Arizona in Tucson, said questions of safety, quality and sustainability are pushing agriculture in a host of other directions, including Despommier’s vertical farming idea. “He’s one extreme – a very good one,” Giacomelli said.

Several years ago, Giacomelli and collaborators in Arizona explored another extreme when they won a contract to design and build a growth chamber within a new building at Antarctica’s Amundsen-Scott Research Station. The chamber can be tweaked remotely by scientists back in Arizona but is now largely managed by volunteers at the station.

Besides supplying some much-needed color and light for the research station’s residents during Antarctica’s bleak and bitterly cold winter months, the indoor chamber has yielded a range of crunchy greens, tomatoes, cucumbers, hot and sweet peppers and even cantaloupe. Next year, a student will try to grow watermelon in what is arguably the worlds’ most inhospitable place for a garden. Remarkably, the plot has produced about two-thirds of what top greenhouses in North America can deliver.

“I like to say that we can grow any plant anywhere and any time, but for a price,” Giacomelli said. The catch in Antarctica is that electricity  for the lights and pumps has inflated the cost to about $50 per pound of fresh vegetables . “Now, the local person at the supermarket would say you’re crazy for spending that much money on vegetables,” he said. “But you give that number to NASA and they’d say, ‘Wow, that’s a good number.’”

Transportation costs
Back on Earth, Despommier said urban farms could defray some of their own expense by significantly cutting transportation costs. And as the local food movement gains in popularity with environmentally conscious consumers, he said, what could be more local than vertical farming? Despite a lack of major technological advances, the effort also stands to benefit from small but steady improvements in hydroponics and automated systems to control temperature, humidity and nutrient delivery, according to Giacomelli.

To curb the excessive reliance on electricity, Giacomelli’s own group is planning to experiment with fiber-optic tubes called solar pipes that can capture sunlight from the Antarctic growth chamber’s roof. Meanwhile, Utah State University researchers have developed a clear piece of curved polyethylene that can retain heat in the ground and extend the growing season by up to four months for summer squash and tomatoes.

As for keeping up with global food demand by growing crops such as rice and wheat,  “we’re going to have to get better at farming marginal lands,” Bugbee said, “but it’s still going to be done outside because the sunlight is so cheap — well, free — and the sunlight levels are so high in the summer.”

He agrees that some farming will move toward more controlled environments, especially for high-value crops like fresh herbs that otherwise would be difficult to supply year-round. “Chefs will pay a lot for fresh basil,” Bugbee said, “but we’re not going to feed the world with that.”

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