Published by City Farmer, Canada's Office of Urban Agriculture


Why Urban Agriculture?

Notes for the IDRC Development Forum on
Cities Feeding People: A Growth Industry
Vancouver, BC
20 May, 1997

William E. Rees, PhD
University of British Columbia
School of Community and Regional Planning
6333 Memorial Road Vancouver, BC V6S 1Z2
Phone: (604) 822-2937 Fax: (604) 822-3787
William Rees

Why Urban Agriculture?


These notes introduce the context and rationale for renewed interest in urban agriculture in both high-income and less developed countries around the world. Urban agriculture includes any activity associated with growing crops and some forms of livestock in or very near cities for local consumption, either by the producers themselves or by others when the food is marketed. Agriculture in cities plays an important role in population health, local economies, and community development wherever it flourishes. While more common in cities of the developing world as a matter of necessity, interest in city farming - and the need for it - is increasing in the cities of the North.


We live in an increasingly urban world. Seventy-five percent of the people in so-called industrialized countries already live in towns and cities and urbanization has become a global phenomenon in the last half-century. The resultant mass movement of people from farms and rural villages everywhere constitutes the greatest human migration in history. It seems likely that fully half of the human family will be city dwellers by the year 2000.

While urbanization is usually thought of as a demographic or economic phenomenon, it also has major ecological consequences. More importantly, from the perspective of ecosystems integrity, cities significantly alter natural biogeochemical cycles of vital nutrients and other chemical resources. Removing people and livestock far from the land that supports them prevents the economic recycling of phosphorus, nitrogen, other nutrients and organic matter back onto farm- and forest lands. In short, as a consequence of urbanization, what were once local, cyclically integrated ecological production systems, have become global, horizontally disintegrated throughput systems. For example, instead of being returned to the land, Vancouver's daily appropriation of Saskatchewan mineral nutrients goes straight out to sea.

As a result of this process, agricultural soils are degraded - more than half the natural nutrients and organic matter from much of Canada's once rich-prairie soils have been lost in a century of mechanized export agriculture - and we are forced to substitute non-renewable artificial fertilizer for the once renewable real thing. All of this calls for much improved accounting for the hidden costs of cities, of transportation, and of mechanized agriculture, and a redefinition of economic efficiency to include biophysical factors (Rees and Wacketnagel 1996).

A major socio-cultural consequence of urbanization is that people are first spatially and then psychologically distanced from the land that supports them. To many urban dwellers, even food, that most vital of basic needs, is increasingly dissociated from its origins in the sun and soil. Once the final product for market, food at the farmgate today is only raw material for an elaborate - and mostly urban - processing industry. Indeed, most wealth generated by the food sector in the North is in value-added processing, packaging, transportation, and retailing, effectively trivializing farming per se as economic activity and way of life. Little wonder that food and farming occupies a diminished place in the consciousness of city folk everywhere in the "developed" world.

Rich Country Paradox

Urbanites' alienation from the land is abetted by the fact that in Canada our 390,575 farm operators comprised only 1.4% of the population in 1991. Farm operators plus household members totaled only 3% of the population, down from a peak of 31% in 1931 (Harrison and Cloutier 1995). In the United States, by 1988 only three million individuals (2% of the population) owned farmland and 44% of these owners leased out rather than worked their land. The two million farms and actual farm operators represented only 1.3% of the population (USDA 1994). Similarly, in Britain, agriculture employs only 2.2% of the people. These data explain how many urban North Americans and Europeans can live their entire lives without meeting a farmer or anyone else engaged in primary agriculture.

To make matters worse, in our industrial culture, short-term economic logic and the language of efficiency has come to override most other values and considerations in both public and private life. In these circumstances, far from being treated with special reverence, food-lands have been thoroughly commodified. To many academic analysts and land-owners alike, agricultural land is just another tradable good and farming must compete for it with other uses. So it is that some of the world's finest agricultural lands now earn higher economic returns as parking lots and shopping centers sprawling around the suburbs of cities everywhere.

Thus, we have a paradox. Food is vital to survival, and the availability of cheap, high-quality food is taken for granted by most people in high income countries, yet agriculture has been thoroughly marginalized both in the national landscape in the modern consciousness (Rees 1997). In these circumstances, most Northern urban dwellers' idea of "urban agriculture" is the back-yard gardens of a few people who like to grow tomatoes and other table vegetables as a hobby. Very few are able to envisage either the need for, or the potential benefits of, urban agriculture as a serious activity.

Poor Country Necessity

The situation in North America and Europe could hardly contrast more with those in many less developed countries. Far from taking their next meal for granted, up to a billion people on Earth today are chronically under-nourished and spend much of their time scrounging for food. As the forces of globalization, structural adjustment, and land use "rationalization" displace increasing numbers of people from the land, and as once rural populations seek employment in the burgeoning cities of the South, the challenge of feeding the new urban millions takes on formidable proportions.

In this light it is hardly surprising that urban agriculture already plays an increasingly vital role in the physical and economic survival of many people in southern countries. In some cities, a fifth to a third of families are engaged in agriculture, and some have no other source of sustenance or income. According to the 1988 census in Tanzania, urban farming was the second largest source of employment in Dar es Salam, providing work for 20% of the adult population. Sixty-four per cent of the residents of Nairobi grow at least some of their own food. In Kathmandu, Nepal, 37% of food producers meet all their household vegetable needs and 11% of animal product needs by their own hand. Even in densely populated Hong Kong , 45% of local vegetable needs are met through intensive cultivation of just six per cent of the local land area (Garnett 1966).

Freeman (1991) documents four major motivations and roles for city farming in the developing world: to satisfy basic hunger; to supplement an excessively starchy diet; to supplement family income; and to reduce expenditures on food to allow other purchases. Despite these dietary and socioeconomic realities, central governments often do not support urban agriculture. Indeed, many ignore or actively discourage it.

Trends to Watch

This neglect may be about to change as agriculture generally enters a new phase world wide. Global food production seems to be stalling even as demand and prices rise at a rate unprecedented in the post WW-II period. Despite rising demand, per capita grain production has actually been in decline since at least the mid-1980s as has the area of grainland available per capita. Indeed, some 86 million ha of severely degraded land (twice the area of Canada's cropland) has been lost to production. Most potentially arable land on Earth is already under cultivation and many authorities believe that farmers in the more productive areas have already got the most out of many technologies that were behind the green revolution (e.g., irrigation, fertilizers, pesticides) (Gardner 1996, Brown, et al. 1997). Meanwhile, global fish catches also seem to have peaked in 1989 at about 100 million tonnes [including by-catch]) and have been steady or in decline ever since (this catch level is near the theoretical maximum sustainable yield of present fisheries). Even without any external shocks, an additional 90 million people per year, together with rising incomes particularly in China and South-East Asia, suggests a tightening relationship between global supplies and demand for food. This situation is already making food less available to millions of impoverished people around the world.

Unfortunately, the future may well be characterized by "external shocks." Evidence that global climate change is underway (rising mean temperatures, increasing frequency and duration of extreme weather events, accelerating meltdown of the Arctic pack-ice, Antarctic ice-shelves, and montane glaciers), and studies showing that ozone depletion is affecting the productivity of southern oceans, increase the already considerable uncertainty associated with global food production. Can we continue to assume that we can increase agricultural output in coming decades with the same facility as in the post-war period? Will it be possible even to maintain production at historic highs in the world's major food producing regions?

These questions, and our inability to answer them confidently, suggest that the sustainability of the world's major cities is more fragile than previously thought. Urban agriculture - food production for cities in and near cities - is one way of reducing the vulnerability of the world's urban populations to global ecological change. City farming should therefore become an element of urban land use and social planning for sustainable development in virtually all countries of the world.

Other Benefits of Urban Agriculture in an Unsustainable World

In addition to helping stabilizing food supplies, urban agriculture in both high-income and developing countries can contribute to global sustainability in many other ways:

Fossil fuel use for transportation generates about a third of global carbon dioxide emissions (a "forcing mechanism" in climate change), and global trade alone accounts for 1/8 of world energy use (Goldsmith 1996). Much international and intra-national transportation is food-related. In the industrial world a typical mouthful of food travels 2000 km from farmgate to consumer. Even in relatively tiny Britain, food related transport accounts for 25% of all trips (Garnett 1996). Thus, local food production for local consumption has considerable potential to reduce the need for transportation and thus the rate of atmospheric CO2 accumulation and possible climate change;

Low-grade waste heat in the cooling water from urban electrical generation facilities can be used to heat and irrigate urban greenhouses increasing both the economic efficiency of energy use and the ecological efficiency of the greenhouse by extending the growing season and productivity;

Locally produced foods require less packaging and refrigeration and other preservation measures thus reducing the packaging waste stream, energy use, and the chemical load in foodstuffs;

Locating food production areas in or near cities makes it possible to consider means to close the nutrient cycles associated with human food production and consumption. Domestic organic waste (including human liquid and solid waste) can be treated, composted, or otherwise processed into soil conditioner and fertilizer and returned to nearby garden and farmland. This produces numerous ecological and economic savings:

  1. It reduces the amount of organic matter and nutrients currently being wasted in landfills or contributing to ground and surface water pollution near cities. This has the side benefit of reducing the rate of methane emission (a major greenhouse gas) from landfills.

  2. The use of organic fertilizers reduces the fossil fuel consumption associated with manufacturing and distributing artificial fertilizers, thus conserving energy, further lowering CO2 emissions, and extending the life of phosphate mines.

  3. Organic compost reduces the amount of artificial fertilizer required by farmers while maintaining the organic and nutrient content of the soil. This can reduce the potential for farm-related land and water pollution and helps maintain and stabilize soils against erosion.

  4. Finally, urban nutrient recycling programs may lower both operating costs to farmers and food prices for the consumer.

Urban agriculture can contribute to enhancing biodiversity in at least two ways. First, it enables the continued production of rare varieties of fruits and vegetables that may be exquisitely adapted to local conditions (and therefore less in need of chemical maintenance) but which are being displaced by the increasingly uniform production technologies of trade-oriented commercial agriculture and the exigencies of international marketing. (Britain has, for example, several thousand local apple varieties but only a dozen or so are permitted for trade within the European Community). More generally, domestic gardeners tend to grow a wider variety of fruits and vegetables than large-scale commercial growers, conserving unique cultivars that might otherwise die out. Second, a diversity of near and intra-urban crops and croplands will attract a greater variety of bird and animal life that the same lands in more "normal" urban use (Garnett 1996).

Urban agriculture can spawn or help sustaining a range of new industries and employment opportunities in and near cities. These include compost production and supply; seed, tool and related supply houses; marketing and distribution, including rejuvenated farm markets; farmer-consumer cooperatives; exchange trading systems; and farm work itself.

Urban farming can contribute to the rebirth of civil society and development of community as neighbours cooperate in the establishment, management, and supervision of community-owned or accessible garden plots and in the evolution of related activities as described above. For example,

According to the Trends Research Institute, Americans in 1997 are coming to view many of the country's mainstream socioeconomic and political structures obsolete. One potential consequence of this is "a new urban revival that respects community integrity and is driven by escapees from suburbia and by new immigrants. Urban gardening will be among its most visible manifestations" (The Trends Journal 1997, as cited in Yes, 1997.

For all these reasons, it seems that urban agriculture makes sense on ecological, social, and economic grounds virtually everywhere on Earth. Governments should see it as an idea whose time has come.


Brown, L. 1997. State of the World: 1997. Washington: Worldwatch Institute.

Freeman, D.B. 1991. A City of Farmers: Informal Urban Agriculture in the Open Spaces of Nairobi. Montreal: McGill University Press.

Gardner, G. 1996. Shrinking Field: Cropland Loss in a World of Eight Billion. Worldwatch Paper 131. Washington: worldwatch Institute.

Garnett, T. 1996. Farming the City: The Potential of Urban Agriculture. The Ecologist 26:299-307.

Goldsmith, E. 1996. Global Trade and the Environment. In: J. Mander and E. Goldsmith (eds) The Case Against the Global Economy and for a Turn Toward the Local. San Francisco: Sierra Club.

Harrison, R. And S. Cloutier. 1995. People in Canadian Agriculture. Statistics Canada Cat.# 21-523E Occasional. Ottawa: Ministry of Industry and Science.

Rees, W.E. 1997. Ecological Footprints and the Imperative of Rural Sustainability. In: Ivonne Audirac (ed). Rural Sustainability in America. New York: John Wiley and Sons.

Rees, W.E. and M. Wackernagel. 1996. Urban Ecological Footprints: Why Cities Cannot be Sustainable and Why They are a Key to Sustainability. Environmental Impact Assess Review 16:223-248.

USDA. 1994. Agricultural Resources and Environmental Indicators. Agricultural Handbook No. 705. Washington: United States Department of Agriculture, Economic Research

Yes! 1997. Top Trends '97. Yes! A Journal of Positive Futures. Spring, 1997.

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Revised June 2, 1997

Published by City Farmer
Canada's Office of Urban Agriculture