Long before the BP oil spill swept its noxious curtain over the Gulf of Mexico, a less-publicized manmade environmental disaster lurked beneath its waters. This was a so-called dead zone, an area of water where most ocean-dwelling creatures could not survive because of its low oxygen content.
The dead zone was caused by fertilizer, excess amounts gathered up in the runoff from farm fields in the American Midwest. In the course of time, this nutrient soup makes its way down the Mississippi and into the gulf. Once it settles in the Gulf it causes the growth of oxygen-devouring algae to go spiraling off the charts. Sadly, it’s not unique. Similar dead zones can be found in the waters off many of the world’s major estuaries.
Modern farming practices aimed at maximizing yields require heavy application of agricultural chemicals: fertilizer, herbicides, and pesticides. Agriculture burns 20% of the motor fuel used annually in the United States. It is, according to statistics quoted in The Vertical Farm by Dr. Dickson Despommier, the primary source of pollution in the United States. Agriculture also accounts for 70% of the world’s annual consumption of freshwater.
Despommier contends that these practices are not only wasteful but also unsustainable. At the same time, over the next forty years, the demands on agriculture will increase as we struggle to feed a world population expected to feed an additional three billion people. As it is, Despommier points out, a billion or so “go to sleep hungry each night”.
Dr. Dickson Despommier has spent 38 years as professor of microbiology and public health in environmental health sciences at Columbia University. He claims to have “hatched” the idea for the vertical farm in 1991, and since then, has worked on it with the assistance of several of his classes. He believes that he has come up with a way to feed everyone and, at the same time, lower agriculture’s environmental impact. Essentially, it amounts to completely reconfiguring farming as it exists today. Instead of farms that sprawl across hundreds of acres, he envisions crops growing in vertically stacked greenhouses, essentially agricultural high-rises. He summons some persuasive arguments in defense of this idea.
First, vertical farms could be situated almost anywhere. Ideally, they would be built in the heart of cities, only a few blocks away from the dinner tables of consumers. No need to burn vast amounts of fossil fuel trucking produce halfway across the nation. As a bonus, vertical farms could even have a positive impact on urban air quality, taking in carbon dioxide and emitting oxygen.
Secondly, vertical farms could be much more productive than traditional farms. Plants growing within the enclosed environment would be protected from the droughts, storms, pests, and plant-withering diseases. Vertical farms would also enjoy an extended growing season that would permit them to produce several crops a year instead of just one. Despommier believes this would not only allow vertical farms to compete successfully with traditional agriculture, but to one day supplant it.
Despommier dreams of a world where traditional farms are redundant along with their polluting practices. Farm fields, no longer needed for growing crops, would be allowed to return to their natural state.
Vertical farms would also consume far less water than traditional farming. Although based on hydroponics, they would use water much more efficiently. Certainly, they would require far less water than the vast quantities currently lavished on irrigation. Aeroponics, a more recent innovation, essentially grows plants by spraying nutrient-laden water onto their roots. An aeroponic facility could save as much as 70% of the water required by conventional agriculture.
In addition, vertical farms could operate very well on reclaimed waste water rather than drinking water. Potentially, they could purify waste water through transpiration, producing potable water as a byproduct. Vertical farms could easily be integrated into urban waste management systems, purifying water from sewage plant outflow and running on energy supplied by burning solid waste.
The relatively low water requirement of vertical farms makes them an especially attractive prospect for agriculture in desert environments, such as in much of the Middle East, where, up till now, large-scale farming has been impossible. Chemical nutrients would be required, but in far lower quantities than traditional farming since there would be little or no waste. Furthermore, the nutrients could be custom-tailored to the needs of specific crops, as could climate. A single vertical farm might house several different environments, each perfectly suited to specific crops.
As radical as Despommier's notion may seem, only the idea of vertical construction is really new. Almost all of the technologies required presently exist. Hydroponics have been in use since the 1930s, and many commercial greenhouses currently grow hydroponic crops for market.
Given Dr. Despommier’s scientific background we might expect this book to be a dry recitation of facts and figures, but nothing could be further from the case. Despommier writes passionately, argues, at times, even stridently. Statistics that are obvious favorites he quotes several times. The focus shifts rapidly to different locations in time and space as he seeks to summarize the impact of agriculture on local natural environments. He points out how often these impacts result in disastrous consequences disastrous for the human populations that depend on agriculture for survival.
Somewhat disappointingly, the author appears to focus more on the history of agriculture than on the vertical farms themselves. Even then, the focus is more on the environmental justification for vertical farms than on their economics. We are given possibilities rather than fully realized ideas. The author’s intention appears to be to get people thinking about vertical farms, rather than providing all the answers.
The major question the book leaves unanswered is can we afford to build vertical farms on costly urban real estate. In other words, can they compete effectively with existing agriculture? Farms are located in the country because land is cheap there. Agriculture exists as it does because, despite all of the expenses incurred for fuel and agricultural chemicals, it produces profits. In short, unless positive economic reasons for building vertical farms can be found, they won’t be built.
The economics of the future, however, could be very much on Dr. Despommier’s side. More and more expensive agri-chemicals will be needed just to maintain present crop yields, let alone growing enough food to feed an exploding population. Fertilizer costs will soar as raw material deposits are depleted. Even now, the cost of chemical fertilizers is beyond reach in many parts of the world. Farmers there are compelled to make due with human and animal waste, creating attendant health problems.
To date, no vertical farms have been constructed. What remains is to build some test facilities and see if they work. You can see what they might look like online at the vertical farm website. For now, at least Despommier’s idea seems to have engaged the architectural imagination.