Urban Ecocycles and the Metabolism of Cities

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Sir Richard Rogers argues in his book Cities for a Small Planet for the need to replace our linear approach to pollution and re s o u rce use in cities with ones that emphasizes circular systems. What is needed, he argues, is "a new form of comprehensive holistic urban planning" (Rogers, 1997 p. 30). An extension of our view of cities like forests is to appreciate that they are ultimately composed of a complex flow of inputs and outputs— of energy and resources flowing in, and waste and pollution flowing out. Among European cities, there is a growing body of experience and experimentation in support of a circular view of urban metabolism. This chapter examines some of the most important emerging examples. While no European city (or a city anywhere for that matter) has succeeded in fully implementing a circular vision, there are many exemplary beginnings that o ffer inspiration.

There is an explosion of interest in the idea of ecocycles within European cities and the potential of reorienting production and consumption processes so that these ecocycles are in (better) balance. Thinking in terms of the inputs (e.g., energy and food) and outputs (e.g., waters and carbon emissions) has become a useful frame of reference for local sustainability. The rough calculations for London illustrate the magnitude of these input/output flows and suggest opportunities for reducing throughput and more directly tying inputs and outputs (see Table 8.1). London requires an astounding 2.4 million tonnes of food each year and generates some 60 million tonnes of carbon dioxide (Sustainable London Trust, 1997). In the

Table 8.1. The Metabolism of Greater London and London's Ecological Footprint

The Metabolism of Greater London (population 7,000,000) These figures quantify London's resource use. They are listed here to emphasize the huge potential for greater resource efficiency. London's waste output could be used as a significant resource for new recycling and energy efficiency industries.

1) inputs tonnes per year Total tonnes of fuel, oil, equivalent 20,000,000 Oxygen 40,000,000 Water 1,002,000,000 Food 2,400,000 Timber 1,200,000 Paper 2,200,000 Plastics 2,100,000 Glass 360,000 Cement 1,940,000 Bricks, blocks, sand, and tarmac 6,000,000 Metals (total) 1,200,000

2) wastes

Industrial and demolition wastes 11,400,000

Household, civic, and commerical wastes 3,900,000

Wet, digested sewage sludge 7,500,000

Co2 60,000,000

SO2 400,000

NOx 280,000

London's Ecological Footprint

London's ecological footprint, following the definition by Canadian economist William Rees, consists of the land area required to supply London with food, fibre and wood products, and the area of growing vegetation needed to reabsorb London's carbon dioxide output:


London's surface areas: 390,000

Farmland used: 3 acres/person: 21,000,000

Forest area required by London for wood products = 0.27 acres/person 1,900,000

Land area required for carbon absorption (equal to acreage required for fuel production from biomass) = 3.7 acres/person 26,000,000

Total London ecological footprint:

= 125 times London's surface area 48,900,000

Britain's productive land: 52,000,000

Britain's total surface area: 60,000,000

Source: Herbert Girardet, 1995 and 1996; sources available.

words of a study by the Sustainable London Trust: "London has become used to a linear throughput of resources, utilizing raw materials and then discarding them as waste when we are finished with them. To become more sustainable, London needs to reduce its excessive energy consumption, pursue linear resource flows and in the process reduce its waste output" (Sustainable London Trust, 1997, p. 10).

London has far to go in balancing these ecocycles, but other cities in E u rope have done more. One of the most impressive cities in this region is Stockholm, and indeed the ecocycles idea has an especially high degree of currency in Sweden. The key idea here is that cities must begin to look for ways in which, as in nature, wastes represent productive inputs, or "food," for other processes. The city of Stockholm has made some of the most impressive pro g ress in this area. As Figure 8.1 illustrates, the city, and its various companies dealing with elements of the cycles, are moving in the direction of a more coordinated framework. A number of actions in support of ecocycle balancing have already occurred. These include, for example, the conversion of sewage sludge to fertilizer and its use in food p roduction, and the generation of biogas from sludge. The biogas is used to fuel public vehicles in the city and to fuel a combined heat and power plant. In this way, wastes are returned to residents in the form of district heating.

Stockholm's production of heat and energy takes an ecocycle approach in other ways. Several of its combined heat and power plant are fueled by waste dust from a sawmill in the north of the country, first converting the dust into pellets at a compressing plant (owned by the city) and shipping them by boat (also owned by the city) directly to the plant. The result is the use of a renewable energy source and the conversion of a waste stream into a productive good.

In the administrative organization of the city of Stockholm, an ecocy-cles division was created and headed by Green Party vice-mayor Krister Skanberg. It includes the companies dealing with energy, water, and waste. Skanberg explained how the label just seemed to fit. Concern for p romoting more balanced ecocycles in the city aptly describes many of its initiatives. Few cities anywhere in the world are doing as much in this are a.

Skanberg has also been spearheading efforts to incorporate the principles of the Natural Step program into Stockholm city government. Natural Step, the brainchild of Swedish cancer researcher Karl-Henrick Robert, lays out a series of four system conditions that all companies and organizations concerned with sustainability should strive to respect. Complementary to and supportive of ecocycle balancing, these conditions include the following: (1) that substances from the earth's crust must not be allowed to sys-



City Metabolism

Figure 8.1. Ecocycle balancing in Stockholm

The city of Stockholm is beginning to develop a comprehensive ecocycle balancing strategy in which wastes of one activity become productive inputs for other activities. Shown here are some of the key interconnections being made in Stockholm between the city's energy company, waste management agency, and water department. Source: City of Stockholm, ecocycles division.

Figure 8.1. Ecocycle balancing in Stockholm

The city of Stockholm is beginning to develop a comprehensive ecocycle balancing strategy in which wastes of one activity become productive inputs for other activities. Shown here are some of the key interconnections being made in Stockholm between the city's energy company, waste management agency, and water department. Source: City of Stockholm, ecocycles division.

tematically increase in the ecosphere; (2) that substances produced by society must not be allowed to systematically increase in the ecosphere; (3) that the physical basis for productivity and diversity of nature must not be systematically diminished, and (4) that there should be fair and efficient use of resources with respect to meeting human needs (The Natural Step, 1996). (The history and background of the Natural Step is discussed in greater detail in Chapter 11.) Skanberg has been successful in Stockholm, and the system rules of Natural Step have been included word for word in the city's new environmental policy. It is not clear what status this policy will actually have, but Skanberg believes it will be frequently referred to and will help to shape and guide the council's decisions in the future. In his words "Of course the council could decide to forget what it decided, . . . but words have an enormous impact once printed." Skanberg admits that people have been skeptical about the Natural Step program. "Some ask 'Is this a religion or what?'" he says. While the concept has been more often adopted by businesses and corporations, he sees no reason why government should not also embrace it.

Specific evidence of implementation of a Natural Step agenda is premature, but Skánberg points to several recent initiatives that move the city in this direction. One involves his efforts to reform purchasing policies and practices in the city. The companies and offices over which he has some control amount to about 2 billion Swedish kroner, and he believes there are many ways in which these purchase decisions could be made more in line with ecocycle ideas. A set of environmental guidelines has already been prepared to guide purchasing contracts, which lays out both unacceptable impacts or practices, as well as the things that should be discouraged. These guidelines have been given to potential contractors, and Skánberg feels that the message is getting out that those who do business with the city will be scrutinized and held to a high environmental standard.1 The entire city government is now in the midst of examining and inventorying its environmental impacts with the goal of certification under the EU's Eco-Management and Audit (EMAS) program.

One interesting recent pilot program in Stockholm that further shows the potential of the ecocycle idea is a program called "from table to soil" (translated from the Swedish "fran bord till jord"). Under this pilot program, organic wastes are collected from participating restaurants and certain kitchens and are processed through a digester, generating biogas (fertilizer). The fertilizer has been used on farm fields in the production of crops. An evaluation study of the pilot's first year indicates generally favorable results. The study found low levels of contamination in the fertilizer and a high production of biogas. The feeling is that with the results so positive, the program will be extended to the entire community. And, Skánberg would like to have a similar process for household organic wastes (although these wastes are not usually as clean).

Can Vice-Mayor Skánberg ever imagine these kinds of initiatives really and fundamentally bringing the city's ecocycles into balance? In the short term probably not. But in the longer term, he is more optimistic. He predicts that in fifty years the situation will have changed dramatically— instead of 10 percent of the city's cycles in balance and 90 percent out of balance, the reverse may be the case.

Stockholm's experience shows the strong importance of cooperation between and among the different agencies, companies, and branches of city government. Skánberg notes the remarkable transformation in thinking since the green-red coalition came into power in his city. He believes staff in all the departments feel freer and more inclined to think green. A main obstacle in the past has been a kind of conservatism—staff afraid to bring up things, to look for interconnections, to think creatively especially if they expected that their ideas would not be appreciated or met with a positive reaction. There is clearly a new, more positive climate in Stockholm city government, and Skanberg says he gets calls all the time to come and visit the departments and to discuss new ideas.

Stockholm is not the only Swedish municipality pursuing an ecocycles approach. Goteburg, for example, has also received well-deserved attention for its efforts in this area. This port city took an explicit ecobalancing approach to preparing its structural (comprehensive) plan in the early 1990s. Specifically, it prepared "material cycles" (analyses) for water and nitrogen, and later carbon dioxide (Berggrund, 1996). These analyses showed the interconnections and linkages between different community sectors and activities, and the major sources of emissions (in the case of nitrogen). Information about these cycles and elements of the metabolism of the city were then used in engaging citizens and politicians in consultations about the structure plan. "Eco-balancing studies . . . have increased awareness about linkages between land development and material flows and cycles in the city and the local environment. They have educated policymakers and residents about the metabolism of the city and about the imbalances in the city's imports of materials and exports of wastes. These studies have mobilized support for work on sustainability and have provided the opportunity for consideration of ecological cycle issues in urban planning. The future challenge is to develop an eco-balancing tool or model that will have more direct input into the structural planning process" (Berggrund, 1996, p. 96).

The Swedish municipality of Ystad has undertaken its own ecocycles program to create more sustainable relationships between the city and the surrounding countryside, and to identify where it can promote local decentralized approaches to dealing with necessary inputs to and outputs from the city. The ecocycles project there yielded a host of projects, ideas, and planned changes in local practice, including a move toward organic waste treatment, the restoration of biodiversity on municipal lands, promoting and encouraging local food production (including a study of patterns of food production and consumption in the city), and investigation of local farmland producing bioenergy (already 60 percent of the fuel for its district heating system comes from energy crops). Much of the early effort here has been focused on studying these issues and engaging the public in a dialogue about the possibilities for the future (European Academy of the Urban Environment, 1996). So far, a major achievement here has been a "new way of thinking among public officials and a large section of the population ..." now "tries to integrate ecological and environmental aspects and takes a more holistic viewpoint of issues" (European Academy of the Urban Environment, 1996, p. 5).

Examples of other Scandinavian cities pursuing ecocycle balancing strategies can be cited, although few rise to the level of Stockholm's effort. The Swedish town of Eslov, for example, also extracts biogas from sewage and organic wastes and sends this as fuel for a neighborhood heating system. As a result, the cost of waste treatment here is paid for from the sale of the gas. (And, the amount of sewage sludge generated in the process has been dramatically reduced [European Commission, 1996].)

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