SIEMENS

Dickson Despommier, a parasitologist at Columbia University in New York City, has an office on the second floor of a 15-story building overlooking the Hudson River. From here he can see the George Washington Bridge and the wooded cliffs of New Jersey on the opposite bank. Despite his great location, the 70-year-old scientist is dreaming of a very different kind of high-rise.

What Despommier has in mind is the following: a 30-story skyscraper with a transparent facade behind which green colors ranging from pastel to emerald hues shimmer in the sun. Instead of having interior walls, each floor would contain hydroponic fields of wheat, barley, or corn; shelves with lots of vegetable plants and colorful flowerbeds; areas in which chickens would be free to roam; and water tanks for breeding fish or shrimp. Heat and light would come from solar cells, geothermal sources, wind or hydro power, and fertilizer would be obtained from the sewage system and livestock manure.

This is Despommier’s vision of a "vertical farm" that would provide fresh food to thousands of people from a downtown location. And while the idea might seem bold, it actually fits in ideally with the current wave of modern green urban planning, as the skyscrapers would simply add another urban oasis to complement today’s parks. What’s more, people could obtain fresh vegetables, fruit, grains, and poultry every day from such farms, thus eliminating the need to have food shipped in from afar - not to mention from the other side of the globe. "Many environmentally-conscious people say we need to purchase locally produced food - but you can’t get any more local than your own neighborhood," says Despommier.

Despommier has two arguments that support his vertical farm concept. The first involves global population growth. The U. N. estimates that by 2050, more than nine billion people will be living on the planet, the majority of them in cities. This will create the need for almost one billion more hectares of arable land - an area around the size of Brazil.

Second, vertical farms would help to fight climate change in two ways, as Despommier explains: "On the one hand, food produced locally all year round would have a tremendously positive impact on transport and refrigeration costs, as well as on CO₂ emissions. In addition, land currently used for agriculture could be returned to nature, creating giant carbon sinks."

There’s no doubt that Despommier is reaching for the skies, so to speak. Nevertheless, the concept he and his students came up with ten years ago could be feasible. For example, highly efficient greenhouses have existed for some time in places where one might not expect to find them. One such greenhouse, known as Eurofresh, is in the middle of the Arizona desert. At 128 hectares, it’s the largest hydroponic greenhouse in the U.S., and is capable of delivering produce all year round, including 80,000 metric tons of tomatoes annually. The greenhouse also requires around 70 percent less water than a conventional field, while occupying much less space. That’s because in a hydroponic system, water enriched with nutrients is not absorbed by soil but instead provided directly to the plants rooted within a container of soilless material - and where there’s no soil there are fewer pests. Dangerous diseases and parasites are thus less of a problem here than in open fields, which means fewer pesticides are needed as well.

According to Despommier, Eurofresh demonstrates just how much can be grown indoors today using state-of-the-art technology. Still, he criticizes the fact that Eurofresh is located too far from a major metropolitan area and delivers too much of its produce throughout the entire U.S. "Even if you leave out the transport and energy costs, a lot of vegetables spoil en route," he explains. Nevertheless, Despommier envisions his vertical farms as something akin to Eurofresh, except his facilities will be multi-storied and located directly in urban areas.