Urban Farming: Crops Grown Right Downtown?


Until now, the agricultural industry could keep up well enough -- otherwise swelling population figures would have leveled off long ago. But scientists warn that agricultural productivity has its limits. What's more, much of the land on which the world's food is grown has become exhausted or no longer usable. Likewise, there is not an endless supply of areas that can be converted to agricultural use.

By 2050, the UN predicts that the global population will surpass 9 billion people. Given current agricultural productivity rates, the Vertical Farm Project estimates that an agricultural area equal in size to roughly half of South America will be needed to feed this larger population.

Vertical farming has the potential to solve this problem. The term "vertical farming" was coined in 1915 by American geologist Gilbert Ellis Bailey. Architects and scientists have repeatedly looked into the idea since then, especially toward the end of the 20th century. In 1999, Dickson Despommier, a professor emeritus of environmental health sciences and microbiology at New York's Columbia University seized upon the idea together with his students. After having grown tired of his depressing lectures on the state of the world, his students finally protested and asked Despommier to work with them on a more positive project.

From the initial idea of "rooftop farming," the cultivation of plants on flat roofs, the class developed a high-rise concept. The students calculated that rooftop-based rice growing would be able to feed, at most, 2 percent of Manhattan's population. "If it can't be done using rooftops, why don't we just grow the crops inside the buildings?" Despommier asked himself. "We already know how to cultivate and water plants indoors."

With its many empty high-rise buildings, Manhattan was the perfect location to develop the idea. Despommier's students calculated that a single 30-story vertical farm could feed some 50,000 people. And, theoretically, 160 of these structures could provide all of New York with food year-round, without being at the mercy of cold snaps and dry spells.

The Power Problem

Despite these promising calculations, such high-rise farms still only exist as small-scale models. Critics don't expect this to change anytime soon. Agricultural researcher Stan Cox of the Kansas-based Land Institute sees vertical farming as more of a project for dreamy young architecture students than a practical solution to potential shortages in the global food supply.

The main problem is light -- in particular, the fact that sunlight has to be replaced by LEDs. According to Cox's calculations, if you wanted to replace all of the wheat cultivation in the US for an entire year using vertical farming, you would need eight times the amount of electricity generated by all the power plants in the US over a single year -- and that's just for powering the lighting.

It gets even more difficult if you intend to rely exclusively on renewable energies to supply this power, as Despommier hopes to do. At the moment, renewable energy sources only generate about 2 percent of all power in the US. Accordingly, the sector would have to be expanded 400-fold to create enough energy to illuminate indoor wheat crops for an entire year. Despommier seems to have fallen in love with an idea, Cox says, without considering the difficulties of its actual implementation.

Getting Closer to Reality

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