By 2050, 80% of the earth’s population will live in cities and 3 billion more people will need to be fed. The simple fact is we are running out of available land to grow enough food to feed them. If we can’t grow our cities outward to find more arable land, the only solution is to grow them upwards. This may change the way we design cities forever.
The problem is real and immediate. Even by most conservative estimates of demographic trends, population growth will require more land than is available to grow enough food to feed them using traditional farming practices. Over 80% of the earth’s land suitable for raising crops is already in use according to the UN’s Food and Agriculture Organization (FAO) and while much of this land has been laid waste by poor agricultural management practices, even its recovery will not be sufficient.
Urban agriculture is not new. Throughout the ages, city dwellers have grown food in whatever free space was available or in rooftop gardens. In ancient Rome and in Persia aqueducts carried mountain water to support intensive city-based food production. Visitors to the ruins of Machu Picchu still marvel on how water was used and reused to grow vegetables in this inhospitable mountain fortress. Victory gardens during World Wars 1 and 2 were used to grow fruit, vegetables and herbs in the US, Canada, and UK to reduce pressure on food production needed to support war efforts.
Today, rising food prices and growing urban poverty have sparked a new interest in community gardening in many cities, where abandoned inner city properties have been turned into productive food growing assets. Urban farming has taken root in Detroit, New York, Vancouver, and many other cities around the world.
Many have asked, could we make our cities more sustainable - even food self-sufficient - if the need to grow food locally was included into every stage of urban design and new building construction - from drawing board to decor?
The answer is simply that, while it will help, it will not be enough. A whole new concept of urban land use for farming will be required to accommodate another 3 billion people, and an entirely new approach to indoor farming using cutting-edge technologies must be invented.
This is where the concept of the vertical farm comes in.
The Vertical Farm
The vertical farm is a theoretical construct whose time has arrived, for to fail to produce them in quantity for the world at-large in the near future will surely exacerbate the race for the limited amount of remaining natural resources of an already stressed out planet, creating an intolerable social climate, notes Dickson Despommier of the Department of Environmental Health Sciences Mailman School of Public Health, Columbia University in an essay on The Vertical Farm.
Despommier noted in another article that he told his students to 'forget about money, space and time, and design a building that will feed and hydrate 50,000 people a year.' I wanted individuals to eat 2,000 calories a day and drink water created by evapotranspiration' he said.
That is where the idea took root and the design parameters of the vertical farm began to take shape. It is estimated that one vertical farm with an architectural footprint of one square city block and rising up to 30 stories (approximately 3 million square feet) could provide enough nutrition (at 2,000 calories/day/person) to comfortably accommodate the needs of 10,000 people employing technologies currently available.
Greater yields per square foot are theoretically possible, though additional research will be required in hydrobiology, engineering, industrial microbiology, plant and animal genetics, architecture and design, public health, waste management, physics, and urban planning.
The vertical farm could grow fruits, vegetables, grains, and even fish, poultry, and pigs. But more than growing crops indoors, it would also generate its own power from waste and clean up its own sewage water for reuse. Cities already have the density and infrastructure needed to support sky farming, and super-green skyscrapers could supply not just food but energy, creating a truly self-sustaining environment.
Despommier estimate one acre of vertical farm could be equivalent to as many as ten to twenty traditional soil-based acres, depending upon which crop species is considered. And growing food close to home would lower significantly the amount of fossil fuels needed to deliver it to the consumer, not to mention that required for ploughing, applying fertilizer, seeding, weeding, harvesting, etc..
The concept of faming in three dimensions could eliminate many of the external natural processes that confound the production of food, since crops will be grown indoors under carefully selected and well-monitored conditions, insuring an optimal growth rate for each species of plant and animal year round.
The advantages of vertical farming include:
- Year-round crop production
- Elimination of agricultural runoff
- Significant reduction of fossil fuels for farm machines and crop transportion
- Better use of abandoned or unused properties
- No weather related crop failures
- Improved sustainability for urban centers
- Conversion of black or gray water to drinking water
- Provision of energy back to the grid via methane generation
- Creation of new urban employment opportunities
- Reduction of infection transmission risks
- Control of vermin by using restaurant waste for methane generation
Many vertical farm designs have been brought forward; a veritable feast of vertical farm concepts is available at 'The Living Skyscraper: Farming the Urban Skyline' produced by Blake Kurasek of the Graduate School of Architecture, University of Illinois at Urbana-Champaign.
An example of a Sky Farm proposed by Gordon Graff for downtown Toronto’s theatre district is shown below. It has 58 floors, 2.7 million square feet of floor area and 8 million square feet of growing area, which can produce as much as a thousand acre farm, feeding 35,000 people per year.
Entrepreneurs in Las Vegas announced plans earlier this year for the world’s first 30 story farm, and various proposals have been brought forward for New York, Seattle (mixed farm-residential design), and Toronto.
In reality, a vertical farm is more likely to appear first in a country where arable land is already in short supply, such as Japan, Iceland, or Dubai. Despommier is convinced the first vertical farm will exist within fifteen years - and oil money could very well build it.
Simple, but not easy
The simplicity of the concept and its potential advantages do not outweigh other issues associated with urban agriculture, including those which are overlaid with social equity concerns. Urban agriculture is often focussed on meeting the needs of the urban poor. In developing countries most urban agricultural production is for self-consumption.
Marshalling the investment capital and the technologies needed to create a viable (and profitable) vertical farm is every bit as complicated as securing financing and basic inputs for traditional agriculture, except the existing panoply of farm and crop subsidies likely would not come into play. Adding the social equity dimension (i.e. feeding the urban poor) raises many more bottom line issues that could discourage many investors.
City Governments can help
City governments have an important role to play to make urban agriculture a reality. Through such means as tax relief, equity partnerships, access to free land, supportive zoning changes, relaxation of by-law restrictions, etc., as well as assuming responsibility for collateral side issues such as poverty reduction and social equity, city governments can set the stage for demonstration projects that would be needed to prove the conceptual and technical feasibility of vertical farming.
Just as many cities are now acting to facilitate waste-to-energy demonstration projects (e.g. for example Plasco Energy received property-tax exemptions from the City of Ottawa, which is a partner in a test waste-to-energy plant to be tested in that city), so too will adjustments be required to bring a full scale demonstration vertical farm project into being.
The City of Vancouver has taken an important first step in promoting urban agriculture. Though not on the scale of high rise farms, plans for the redevelopment of the Southeast False Creek area of the city include regulatory and zoning changes designed to promote community-based food production. See the related Case Study.
The Urban Revolution
The concept of cities feeding people goes far beyond questions of technical feasibility and urban land management. To feed an additional 3 billion people, most of who will be living in cities, will require nothing less than a revolution in our concepts of urban form and in the economic systems that support agriculture, energy, transportation, housing, industry and social welfare.
Even Despommier acknowledges this. 'The first buildings would have to be subsidized, with energy incentives and tax incentives, 'he says. 'We’re talking about the equivalent of engineering a Saturn rocket.'
Despommier has been contacted by scientists and venture capitalists from the Netherlands to Dubai who are interested in establishing a Center for Urban Sustainable Agriculture. He estimates it could take a working group of agricultural economists, architects, engineers, agronomists, and urban planners five to ten years to figure out how to marry high-tech agricultural practices with the latest sustainable building technology.
But before we see blocks of vertical farms in cities and towns around the world, much more work is required. The greening of our cities is inevitable, but it will not come easily. Hopefully the urban revolution will not be as destructive to the environment as was the industrial revolution of the 18th and 19th centuries.