Figure 3.4 indicates how between 1910 and 1970 the energy inputs to food produced in the USA


Figure 3.4

Figure 3.4 Energy input to food production from farmer to consumer in the USA: the number of calories put into the system to obtain one calorie of food. Probable values used for 1910 to 1937.

increased. Up to about 1920, the amount of energy used to produce and supply food to the consumer roughly equalled the amount of energy released when the food was eaten. By 1970 the amount of energy used to produce food had increased on average by eight times. So for every one unit of energy supplied to a person when eating food, eight times as much energy had gone into produc­ing that food. This is a significant increase in the energy required for food production.

Ratios between the energ...



One of the most effective ways of assessing the envi­ronmental impact of a particular process or product is to find out how much non-renewable energy is required to produce it; this quantity of energy is referred to as embodied energy. The consumption of embodied energy results in the emission of green­house gases, which contribute to global warming and climate change. So embodied energy can be thought of as a shorthand for assessing the climate change potential of a process.

Another important reason for finding out how much energy different processes and products use is to judge how equitably the world’s resources are distributed. In 1985 the per capita carbon diox­ide emissions for someone living in Africa was




Urban agriculture can result in environmental, social and economic benefits. There are three primary environmental benefits from organic urban agricul­ture – preserving biodiversity, tackling waste and reducing the amount of energy used to produce and distribute food.

Modern industrial farming techniques in the countryside have had a devastating effect on bio­diversity. The combination of fertiliser and pesticide use with habitat destruction means that urban envi­ronments are now often more species-rich in fauna and flora than their rural counterparts (Nicholson – Lord, 1987).

Added to this has been the effect of a few large supermarket chains dominating food retailing...



Let’s start by considering how we have reached this state of affairs and why architects, urbanists and plan­ners have a role to play in improving the situation.

In the English speaking world, the publication of Carson’s Silent Spring in 1962 triggered concern over the ecological side effects and health risks posed by industrial agriculture and agribusiness, resulting in chemically dependent farming techniques. Today, many rural areas have been reduced to biologically impoverished wastelands and in Britain, for example, the domination of industrial agriculture is creating an increasingly depopulated landscape.

The increased disconnection between consumers and producers of food means that urban popula­tions have little connection with food production and thus have a limited knowledge of the...



Andre Viljoen, Katrin Bohn and Joe Howe

By agriculture only can commerce be perpetuated; and by Agriculture alone can we live in plenty without intercourse with other nations. This therefore is the great art, which every Government ought to protect, every proprietor to practice, and every inquirer into nature improve.

Dr Samuel Johnson 1709-1784 (Johnson,


By the year 2025, 83 per cent of the expected global population will be living in developing countries. . . . Agriculture has to meet this challenge. . . . Major adjustments are needed in agriculture, environmental and macro­economic policy, at both national and inter­national levels, in developed as well as developing countries, to create conditions for sustainable agriculture and rural development.

Agenda 21 (United Nations Con...



CPULs require land, but in return they will enrich cities by reducing their environmental impact and bringing in spatial qualities until then only associated with rural or natural conditions.

The implementation of CPULs will be a slow process varying with the city under consideration. Each city will have to determine the scale and ambi­tion for CPUL infrastructures. A long-established large city, like London for example, provides less scope for integrating CPULs and/or tracts of pro­ductive urban landscape close to its historic centre than it does close to its fringes (see Chapter 24).

Above all, the new open urban space will need. . . space. Land will have to be allocated, reclaimed, recycled or imaginatively found...



Continuous Productive Urban Landscapes are about urban food growing and local consumption. They will include livestock, but consist largely of vegetation which is locally managed: mainly organic vegetables, fruit and trees, planted in rows, planted in groups, fields, patches, etc. Vegetation will be chosen for its inherent extractable energy (i. e. it can be eaten) or its material quality (i. e. it can be worn), then grown, har­vested, traded and consumed. The main production will be carried out by local occupants who rent the land and work it commercially within an individually defined local framework (see Chapters 17 and 25). Cities that decide to support this concept of organic local farming, trading and seasonal consumption will never be fully self-sufficient in food production...



Katrin Bohn and Andre Viljoen


Overlaying the sustainable concept of Productive Urban Landscapes with the spatial concept of Continuous Landscapes proposes a new urban design strategy which would change the appea­rance of contemporary cities towards an unpre­cedented naturalism. Continuous Productive Urban Landscapes (CPULs) will be open landscapes productive in economical and sociological and environmental terms. They will be placed within an urban-scale landscape concept offering the host city a variety of lifestyle advantages and few, if any, unsustainable drawbacks.

CPULs will be city-traversing open spaces running continuously through the built urban environment, thereby connecting all kinds of existing inner-city open spaces and relating, finally, to the surrounding...



It is now widely acknowledged that CPULs have grown alongside three main urban prerequisites: population stability, successful public transport and borough balance.

London’s population had stabilised since about 2040 at nearly 9 million and both the city’s skyline and the city’s outline had ceased expanding.

This was mainly due to the reduced influx of people into London. Worldwide, there are now consider­ably fewer social, economic and political inequali­ties between countries so that moving for better life conditions has been replaced by moving for richer life experience which happens fairly evenly all over the globe...



The urban strategy that enabled CPULs to happen and to grow to what they are now, in 2045, was called Ecological Intensification (named ‘Carrot City’ by London architects a few years later). In London (as in most European cities), this incremental strategy has been applied since about the year 2005.

Ecological Intensification worked by prioritising envi­ronmental urban layers, which were either connected to open space use, or to implementing sustainable technology and activity patterns. Usually, these environmental layers were then superimposed with other locally appropriate layers, such as economic, social, cultural, historical, etc.

As a result of this process, London has become (and is still becoming) a real ‘Carrot City’: sustain­able, integral, working out of itself, but within its...