Everybody wants greener cities. It makes sense for a lot of reasons: Greenery helps infiltration and reduces flood problems, it lowers air temperatures and thus alleviates the heat island effect, reduces noise and improves air quality, and when producing food it can bring down transport needs and feed the urban poor. Above all - green is beautiful!
But how far should the greening of the city go? Is there a point when the urban becomes rural and loses its urban advantage? Will not too much greenery contribute to urban sprawl and increase the intra-urban need for transport? Is it wise to use expensively treated drinking water to irrigate plants? And is urban agriculture really feeding the poor, or is it a side-line business of the already well-off?
Urban agriculture can become acutely important in times of crisis, as noted for example in present-day Greece. Newspapers report about people growing food on their balconies, or moving to the countryside, to enjoy a more peaceful life and nutritional security, as well as finding new ways to connect producers and consumers more directly like in the ‘Potato Revolution.’ This becomes a necessity when people lose jobs and incomes, thus facing real difficulties in acquiring enough food for themselves and their dependants.
There is a long urban history of acquiring food outside of markets: Allotment gardening accompanied the early urbanization and industrialization in Europe, with local authorities, charities and industry providing land for families to garden. This was originally conceived as a way to provide supplementary food and income for the urban poor and thereby reduce malnutrition. After the World Wars, urban agriculture has mainly been associated with community and ecological movements, and more recently as a way to combat climate change and to improve quality of life.
Urban agriculture is a prominent feature of many lower-income cities. In Cuba, the collapse of Soviet support along with US trade embargo boosted self-sufficiency and urban agriculture during the 1990s. The movement seems to sustain itself, with popular and private gardens in Havana organically producing around half of the fruits and vegetables consumed in the city. Several cities around the world are claimed to have similarly high shares of vegetable or poultry produced within city limits.
Agriculture, however, requires space. Allotment gardening and similar land uses are facing stark competition for land from commercial and residential uses. Recognizing the importance of urban agriculture for the local economy, researchers at the Ardhi University in Tanzania are calling for zoning laws to set aside land for agriculture within cities. Allotment gardening is seen as a model in many parts of the world.
Another response to the shortage of urban land for greenery has been the green wall or vertical gardening. Swedish Gus Nilsson in Gaborone, Botswana, was behind the development of a system of intensive horticulture for dry tropical areas, based on walls with built-in containers, where tomatoes grow with roof-top harvested rain-water. The green wall trend has been taken to new heights in Mexico City where the (Nissan-sponsored) NGO VERDEMX has installed three eco-sculptures; combining art with environmental benefits like reducing particles and noise (although plants don’t always thrive in the harsh environment of Mexico City’s traffic).
Roof-top gardening is another way to manage the competition for land, and reportedly it has significant effects on the local air temperature. On a typical day, the temperature of Chicago City Hall roof - holding a near 2000 square metre garden with some 20,000 plants - is almost 40°C cooler than neighbouring conventional (tar) roofs. Whereas the Chicago City Hall roof-top garden is not for pedestrians, the re-entry of greenery in built-up areas may have its main value in human comfort and quality of life. (But only as long as accessibility and security can be maintained in a way as to provide a green lung for urban dwellers of all ages and genders!)
As discussed at the beginning: Urban agriculture as a fall-back during times of crisis is unquestionable. It is also claimed that where women have the main responsibility for feeding families, a family garden is crucial for making that non-market contribution to food security in the household. The extent to which it benefits the urban poor can be questioned. Gardens are often more common among the middle- or upper classes: When I lived in Dar es Salaam during the 90s, the Prime Minister’s garden was full of cows, and chicken were traded by professionals at the university as well as UN agencies. Urban agriculture very much appeared to belong to the upper income echelons.
A major benefit of greening the cities nevertheless remains: Beauty. This was wonderfully echoed in Pablo Gutman’s study of the potential of agriculture for self-consumption as a way to improve nutrition among the urban poor in Buenos Aires: The poor woman hesitates to harvest her vegetables “because they look so pretty and smell so nice.” Is this the chief benefit of greening our cities? I believe so!