Vertical Farms: The Rise of Vertical Farms

The Problem: Feeding the World

The world's 6.8 billion people use land equal to the size of South America to grow food and raise livestock.
By 2050, with a projected population of 9.5 billion, we will need another Brazil's worth of land if farming continues as it does today.
Present: 6.8 \text{ billion people } + \text{ additional cropland the size of Brazil} = 9.5 \text{ billion people}
That much new, arable land simply does not exist.

Environmental Impact of Traditional Agriculture

Agriculture uses 70% of the world's available freshwater for irrigation, leading to contamination from fertilizers, pesticides, herbicides, and silt, making it unusable for drinking.
Continuing current trends, safe drinking water will become impossible to find in densely populated regions.
Farming consumes huge amounts of fossil fuels—20% of the gasoline and diesel fuel used in the U.S.
This contributes to greenhouse gases and links food prices to fuel prices, doubling the cost of eating in most places worldwide between 2005 and 2008.
Climate change could wipe out farming in California by the end of the century (warned by Secretary of Energy Steven Chu).
Deforestation to generate new farmland accelerates global warming.
Agricultural runoff creates aquatic “dead zones” that turn estuaries and parts of the oceans into barren wastelands.
Foodborne illnesses (e.g., Salmonella, cholera, Escherichia coli, Shigella) and parasitic infections (e.g., malaria, schistosomiasis) cause many deaths worldwide.
Using human feces as fertilizer (common in Southeast Asia, Africa, and Central and South America) spreads parasitic worm infections, affecting 2.5 billion people.

The Vertical Farm Solution

Grow crops indoors under rigorously controlled conditions in vertical farms.
High-rise buildings on vacant city lots and multistory rooftop greenhouses can produce food year-round.
Uses significantly less water, produces little waste, reduces the risk of infectious diseases, and eliminates the need for fossil-fueled machinery or transport from distant rural farms.
Vertical farming could revolutionize how we feed ourselves and the rising population.

Doing No Harm

Growing food on land that used to be intact forests and prairies is killing the planet.
The minimum requirement should be to do no further harm to the earth.
Humans have risen to conquer impossible odds before with technological breakthroughs that bailed us out from Malthusian predictions.

The Need for Ecologically Sustainable Technologies

By the 1980s, it became obvious that farming was stressing the land beyond its capacity to support viable crops.
Agrochemicals destroyed the natural cycles of nutrient renewal that intact ecosystems use to sustain themselves.
We must switch to agricultural technologies that are more ecologically sustainable.
Allowing farmland to revert to its natural grassy or wooded states is the easiest and most direct way to slow climate change through the natural absorption of carbon dioxide.

Examples of Nature's Healing

The demilitarized zone between South and North Korea, created in 1953, is now lush and vibrant, fully recovered.
The once bare corridor separating former East and West Germany is now verdant.
The American dust bowl of the 1930s is once again a highly productive part of the nation’s breadbasket.
New England, which was clear-cut at least three times since the 1700s, is home to large tracts of healthy hardwood and boreal forests.

Indoor Farming Techniques

Indoor farming is already becoming commonplace using three techniques: drip irrigation, aeroponics, and hydroponics.
Drip irrigation: Plants root in troughs of lightweight, inert material (e.g., vermiculite) that can be used for years, and small tubes drip nutrient-laden water precisely at each stem’s base.
Aeroponics: Plants dangle in air infused with water vapor and nutrients, eliminating the need for soil.
Hydroponics: Plants are held in place so their roots lie in soil-less troughs, and water with dissolved nutrients is circulated over them.
During World War II, more than 8,000 tons of fresh vegetables were produced hydroponically on South Pacific islands for Allied forces.
Hydroponic greenhouses provide proof of principles for indoor farming.
Crops can be produced year-round, droughts and floods are avoided, yields are maximized, and human pathogens are minimized.
Allows the grower to select where to locate the business, without concern for outdoor environmental conditions such as soil, precipitation, or temperature profiles.

Eurofresh Farms: A Leading Example

The 318-acre Eurofresh Farms in the Arizona desert produces large quantities of high-quality tomatoes, cucumbers, and peppers 12 months a year hydroponically.
However, these operations sit in semirural areas, where reasonably priced land can be found.
Transporting the food for many miles adds cost, consumes fossil fuels, emits carbon dioxide, and causes significant spoilage.

Vertical Farms in the City

Moving greenhouse farming into taller structures within city limits can solve remaining problems.
Buildings might be 30 stories high, covering an entire city block.
Municipal wastewater would be recycled to provide irrigation water.
Remaining solid waste, along with inedible plant matter, would be incinerated to create steam that turns turbines that generate electricity for the farm.

Integrating Food Production into Urban Life

Integrating food production into the tapestry of urban life is a giant step toward making urban life sustainable.
New industries will grow, as will urban jobs never before imagined—nursery attendants, growers, and harvesters.

Practical Concerns and Solutions

Economic Viability: Skeptics question the economic viability given inflated property values in cities.
Location: Every large city has plenty of less desirable sites that often go begging for projects.
Examples: Floyd Bennett Air Force Base in Brooklyn, Governor’s Island, and the 33rd Street rail yard in Manhattan.
Graduate students surveyed New York City’s five boroughs and found no fewer than 120 abandoned sites waiting for change.

Simple Math and Vertical Farm Viability

A typical Manhattan block covers about five acres.
Critics say a 30-story building would therefore provide only 150 acres, not much compared with large outdoor farms.
Yet growing occurs year-round.
Combining factors such as multiple growing seasons, plant densities, and layers per floor, a 30-story building covering one city block could produce 2,400 acres of food a year (30 stories * 5 acres * 16).
A one-acre roof atop a hospital or school, planted at only one story, could yield 16 acres of victuals for the commissary inside.

Amplifying Factors

Droughts and floods ruin entire counties of crops yearly, particularly in the American Midwest.
Studies show that 30 percent of what is harvested is lost to spoilage and infestation during storage and transport.
City farms largely eliminate these issues because food would be sold virtually in real time and on location.
Largely eliminates the mega-insults of outdoor farming: fertilizer runoff, fossil-fuel emissions, and loss of trees and grasslands.

Economic Considerations: Energy and Water

In this regard, location is everything.
Vertical farms in Iceland, Italy, New Zealand, southern California, and some parts of East Africa would take advantage of abundant geothermal energy.
Sun-filled desert environments would use two- or three-story structures to maximize natural sunlight for growing and photovoltaics for power.
Regions gifted with steady winds would capture that energy.

Waste as a Resource

The plant waste from harvested crops would be incinerated to create electricity or be converted to biofuel.
Liquid municipal waste (blackwater) is also very valuable.
New York City occupants produce one billion gallons of wastewater every day, which could irrigate vertical farms.
Meanwhile, the solid by-products, rich in energy, could be incinerated as well.
One typical half-pound bowel movement contains 300 kilocalories of energy when incinerated in a bomb calorimeter.
Extrapolating to New York’s eight million people, it is theoretically possible to derive as much as 100 million kilowatt-hours of electricity a year, enough to run four, 30-story farms from bodily wastes alone.

Investment and Profitability

Upfront investment costs will be high, as experimenters learn how to best integrate the various systems needed.
That expense is why smaller prototypes must be built first.
Onsite renewable energy production should not prove more costly than the use of expensive fossil fuel for big rigs.
Produce to be less expensive than current supermarket prices, which should be attainable largely because locally grown food does not need to be shipped very far.

Desire and Action

Architects, engineers, designers, and mainstream organizations have increasingly taken note.
Many developers, investors, mayors, and city planners have become advocates and have indicated a strong desire to actually build a prototype high-rise farm.
Have been approached by planners in New York City, Portland, Ore., Los Angeles, Las Vegas, Seattle, Surrey, British Columbia, Toronto, Paris, Bangalore, Dubai, Abu Dhabi, Incheon, Shanghai, and Beijing.
The Illinois Institute of Technology is now crafting a detailed plan for Chicago.

Avoiding Past Mistakes

The infamous Biosphere II closed-ecosystem project outside Tucson, Ariz., first inhabited by eight people in 1991, is the best example of an approach not to take.
It was too large a building, with no validated pilot projects, and a total unawareness about how much oxygen the curing cement of the massive foundation would absorb.
If vertical farming is to succeed, planners must avoid the mistakes of this and other nonscientific misadventures.

Promising News

According to leading experts in ecoengineering, such as Peter Head, CEO of sustainability for Arup, an international design and engineering firm, no new technologies are needed to build a large, efficient, urban vertical farm.

Hydroponics, Aeroponics, and Drip Irrigation

Drip Irrigation:
- Plants grow in troughs of lightweight, inert material (e.g., vermiculite).
- Small tubing drips nutrient-laden water precisely at each stem's base.
- Good for grains (wheat, corn).
Hydroponics:
- Plants are held in place so their roots lie in open troughs.
- Water with dissolved nutrients is continually circulated over them.
- Good for many vegetables (tomatoes, spinach) and berries.
Aeroponics:
- Plants are held in place so their roots dangle in air that is infused with water vapor and nutrients.
- Good for root crops (potatoes, carrots).