High-Rise Farms: The Future of Food?
for National Geographic News
|June 30, 2009|
Salads of the future may still be served in bowls, but their ingredients might be grown in skyscrapers.
That's the hope of scientists and architects who are erecting a unique strategy to feed a swelling population on a planet with finite farmland. (Find out more about sustainable agriculture.)
"In another 40 years, there'll be another three billion people. That's the problem," said Dickson Despommier, a professor of public health at Columbia University in New York. "We have to find another way to feed them."
One solution, Despommier believes, is to grow everything from salad greens to staple grains year-round in high-rise buildings at the hearts of urban centers.
This so-called vertical farming could put food within easy reach for billions of people while reducing carbon emissions from shipping crops across continents and oceans, he notes.
(See pictures of glass pyramids, towers of greenhouse pods, and other possible designs for vertical farms.)
"[The concept] is based on technologies already in use throughout the world, mainly high-tech greenhouses," Despommier said.
For example, many existing greenhouses use hydroponics, a technique for growing crops in smaller spaces using nutrient-enriched water instead of soil.
But for now high-rise farming remains just an idea. One challenge is how to stack the greenhouses so that layers of crops get enough light to be grown in a vertical structure, Despommier notes.
That's one of the reasons Bruce Bugbee, a crop physiologist at Utah State University in Logan, is critical of high-rise farming. He says the concept is too expensive to implement and would be a colossal waste of electricity.
"We're talking gigawatts of power, just huge amounts of power [to grow crops indoors], compared to free sunlight outside," he said.
(Related: "Energy Conservation" in National Geographic magazine.)
Typical office light is only about one percent as intense as the full sunlight needed to grow crops, Bugbee notes.
"People get confused about the amount of light needed to get plant yield versus the amount of light needed to keep people happy and productive and healthy," he said. "They are roughly a hundred-fold different."
Despommier counters that architects are already designing buildings to harvest the maximum amount of natural light.
What's more, by incorporating new energy sources such as hydrothermal and wind power, these buildings don't necessarily have to look like typical skyscrapers.
Another consideration is creating a vertical farm design that would be economically viable.
Despommier said he is particularly intrigued by Eco-Laboratory, created by Seattle, Washington-based architectural firm Weber Thompson.
Other proposed buildings, which can be solely farms or mixes of farms and houses, would reach up to 60 stories high.
But the Eco-Lab complex would be just 12 stories tall and would mix residences with gardens that produce food for the local neighborhood.
"This was [an] attempt at something that seemed viable to a developer," said project designer Myer Harrell.
Residents might tend the crops and own equity in their production, or they might assign the work to outside agricultural firms and later purchase the crops at a local market.
Selling the housing at market rate and proceeds from the farmers' market could generate significant funds.
For example, Harrell said, sales of tomatoes and lettuces grown in the high-rise's hydroponic gardens could total about a million U.S. dollars a year, based on revenue minus the base production costs.
The market viability of Eco-Lab, Harrell noted, distinguishes it from taller vertical farm proposals.
"Those [designs] have merit, but it would be difficult for us to see this idea jump to a larger scale right away," he said.
Harrell believes breaking ground on Eco-Laboratory or a similar scaled-down building could be feasible within the next few years. Even the burst housing bubble and global recession, he noted, may work to the concept's advantage, as people become more interested in self-sufficiency such as growing their own food.
(Related video: "Urban Farming Blooms in London".)
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The need for vertical farms is most urgent in Southeast Asian countries, Columbia University's Despommier said. Many of those places have seen increasing crop failures due to extreme weather and disease amid surging population growth.
(Related: "Food of the Future to Be More Diverse?")
Indoor farming eliminates vagaries of the weather, he said. And even if disease destroys a harvest, the next crop can be planted immediately.
Bugbee, the vertical farming critic, has another solution to feed Earth's swelling population: Eat less meat. This would free up land currently grazed by livestock to be sown with food crops.
"That," he said, "is a rock-solid principle if you are looking for a way to be environmentally responsible."
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