DESIGNING URBAN AGRICULTURE FOR. SUSTAINABLE CITIES

With a vision and a strategy the 21st century city will be green, a healthy place for all and will generate zero net pollution. This book offers a vision and a strategy.

Productive urban landscapes have two huge challenges to address: CO2 emissions are projected to increase by two-thirds in the next 20 years, and as the global food production increases so does the number of people going hungry, with the number of urban hungry soaring.

The symbiotic relationship between a productive landscape and the human settlement system is as old as civilization. During the past 200 years that millennium-old positive relationship deteriorated into a further and further separation of town and landscape. The good news is that during the past quarter-century the agricul­ture industry has turned a corner towards greater integration with our modern cities.

One of the earliest archeological evidences of CPULs (4,000 years ago) are the semi-desert towns of Persia. Underground aqueducts brought mountain water to oases where intensive food production was conducted, substantially based on the use of urban waste within the settlement.

A marvellous example in history is Machu Picchu in Peru. The Spaniards did not discover this nutritionally self-reliant city for 100 years. Scarce water was reused time and again, step-by-step down the mountain. Biointensive vegetable beds were designed to catch the afternoon sun and stretch the season. Water and land crops were brought together to resist the frequent mountain frost. There are many such stories from all corners of the earth.

The industrial revolution brought the railroads, chemical fertilizers, petroleum fuel, tinned food and refrigera­tion and a separation of the food system from where we live. Socially this converted to the creation of the ‘city slicker’ and of the ‘country bumpkin’. Ecologically it brought many dreadful patterns of sickness, worst today in the Himalayan city of Katmandu.

Our current industrial and agricultural systems transport by ship, rail, truck and plane over 80 percent of all extracted natural resources to four percent of the Earth’s land and on that urban four percent convert over 80 percent of it to waste and pollution. The interpretation ‘waste is food’ enables us to conceive of operating sys­tems that utilize waste (heat, sewage, waste-water runoff, organic solids, construction debris, etc.) to green the city and feed the urban population of the globe by closing now-open nutrient cycles.

In the later 1970s there emerged reports of a resurgence of agriculture in the city from (alphabetically) Bogota, Dubai, Lusaka, Madrid, Manila, Moscow, New York, Vancouver and from many corners of the globe. A United Nations survey of 20 countries around-the-world and library research conducted in 1991-1993 con­cluded that there was the beginning of a new urban-based food system evolving worldwide.

This book is a 21st century breakthrough in defining an urban design/planning conceptual approach to re­incorporating a productive landscape, including agriculture, into the human settlement (CPULs). As reported in the chapter ‘Food in Time’ in the previous hundred years there were several such models created including famously: Le Courbusier, Paul & Percival Goodman, Ian McHarg, Louis Mumford, and Frank Lloyd Wright. We have both history and great creative minds to guide our hands to this gigantic task.

Agriculture, reaching from fish farming to ornamental shrubs, is moving to the mostly urban market and becoming less centralized in a few corporations. The potential for CPULs it seems to me is eminently work­able based on two characteristics of 21st century cities: constant renewal and constant de-densification.

Cities today are constantly renewing themselves. Yesterday’s factory sites, shopping malls, and housing estates are collapsing and standing idle for a decade or two or three. These sites, which are idle on an interim basis, are a foundational element in the locally-based food system and the ecologically sustainable (green) city.

The emerging 21st century city can be identified as ‘the Edgeless City’. The concepts of city boundary, green – belt, and suburb are all obsolete. The city that was focussed on the river, the seaport, the railyard, and the limited access highway intersection are all obsolete. Cities are becoming formless, edgeless and seemingly endless. In Africa the city extends from Abidjan to Lagos, in Asia from Kobe-Osaka to Tokyo-Chiba, in North America from Portland Maine to Norfolk Virginia, and in Europe from Barcelona to Genoa.

Once enlightened by the CPUL concept our eyes can see possibilities everywhere: the waste heat from supermarket refrigeration is a source of energy for food production, flood plains are productive if producing crops and costly if used for housing, fruit and vegetable production on rooftops saves heating and cooling costs, reduces air pollution and enables fresh cuisine, a security fence is a potential for productive and orna­mental vines.

Greening the 21st century city will improve our health, stabilize our economy and bring us all closer together as we meet in the garden.

Jac Smit, AICP