Vertical farms offer a number of advantages. Roughly 150 of these buildings, each 30 stories tall, could potentially give the entire population of New York City a sustainable supply of food.
With a total population fast approaching 8 billion, world food demand has continued to climb. At the same time, however, the increasingly dire effects of climate change, as well as other environmental factors, are now having a serious impact. Droughts, desertification and the growing unpredictability of rainfall are reducing crop yields in many countries, while shrinking fossil fuel reserves are making large-scale commercial farming ever more costly. Decades of heavy pesticide use and excess irrigation have also played a role. The United States, for example, has been losing almost 3 tons of topsoil per acre, per year. This is between 10 and 40 times the rate at which it can be naturally replenished – a trend that, if allowed to continue, would mean all topsoil disappearing by 2070.As this predicament worsens and food prices soar, the world is now approaching a genuine, major crisis.
Amid the deepening sense of urgency and panic, a number of potential solutions have emerged. One such innovation has been the appearance of vertical farms. These condense the enormous resources and land area required for traditional farming into a single vertical structure, with crops being stacked on top of each other like the floors of a building. Singapore opened the world's first commercial vertical farm in 2012. By the mid-2020s, they have become widespread, with most major urban areas using them in one form or another.
Vertical farms offer a number of advantages. An urban site of just 1.32 hectares, for example, can produce the same food quantity as 420 hectares (1,052 acres) of conventional farming, feeding tens of thousands of people. Roughly 150 of these buildings, each 30 stories tall, could potentially give the entire population of New York City a sustainable supply of food. Genetically modified crops have increased in use recently and these are particularly well-suited to the enclosed, tightly-controlled environments within a vertical farm. Another benefit is that food can then be sold in the same place as it is grown. Farming locally in urban centres greatly reduces the energy costs associated with transporting and storing food, while giving city dwellers access to fresher and more organic produce.
Another major advantage of vertical farming is its sustainability. Most structures are primarily powered on site, using a combination of solar panels and wind turbines. Glass panels coated in titanium oxide cover the buildings, protecting the plants inside from any outside pollution or contaminants. These are also designed in accordance with the floor plan to maximise natural light. Any other necessary light can be provided artificially. The crops themselves are usually grown through hydroponics and aeroponics, substantially reducing the amount of space, soil, water and fertiliser required.
Computers and automation are relied upon to intelligently manage and control the distribution of these resources. Programmed systems on each level control water sprayers, lights and room temperature. These are adjusted according to the species of plant and are used to simulate weather variations, seasons and day/night cycles. Some of the more advanced towers even use robots to tend to crops. Excess water lost through evapotranspiration is recaptured via condensers in the ceiling of each level, while any runoff is funneled into nearby tanks. This water is then reused, creating a self-contained irrigation loop. Any water still needed for the system can be filtered out of the city's sewage system.
Vertical farms also offer environmental benefits. The tightly controlled system contained in each structure conserves and recycles not just water – but also soil and fertilisers such as phosphorus, making the total ecological footprint orders of magnitude smaller than older methods of agriculture. On top of that, the reduced reliance on arable land helps to discourage deforestation and habitat destruction. Vertical farms can also be used to generate electricity, with any inedible organic material transformed into biofuel, via methane digesters.
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