for National Geographic News
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.
"[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.
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