- Email: [email protected]
In search of sustainable human settlements
Ecological Economics 40 (2002) 151– 155 www.elsevier.com/locate/ecolecon
SPECIAL SECTION: ECONOMICS OF URBAN SUSTAINABILITY
In search of sustainable human settlements Prefatory remarks Roberta Capello a,*, Peter Nijkamp b b
a Department of Economics, Politecnico di Milano, Piazza Leonardo da Vinci 32, 20133 Milan, Italy Department of Spatial Economics, Free Uni6ersity, De Boelelaan 1105, 1081 HV Amsterdam, The Netherlands
Needs satisfaction under a regime of scarce goods is the pivotal interest of economics. The last part of the 20th century has shown the emergence of a new type of scarcity, viz. a healthy environment to work and live in. This new scarcity is reflected in the decline in air, water and soil quality as well as in a general decline in biodiversity. The unpriced nature of many environmental goods makes it difficult to incorporate the environment in the normal calculation schemes of rational market behaviour (see Tietenberg, 1995). It is noteworthy that environmental externalities are no longer esoteric events in a normal market system; they have even become a usual feature. The worldwide decay in environmental quality conditions and the gradual depletion of natural resources has become a dominant theme for research and public policy in the last part of the 20th century. The global interest in environmental matters is partly caused by the increased pressure that a mounting population and increased production exert on the earth’s natural resource base. In addition, as personal incomes rise and leisure time becomes more freely available in the developed world, concern with * Corresponding author. E-mail address: [email protected] (R. Capello).
more immediate human needs has been accompanied by an interest in preservation and conservation for future generations and in other regions of our world. We observe an increasing interest in quality —next to quantity —as an important constituent of individual and collective welfare in which the environment assumes a prominent position on the Maslow needs hierarchy (see also Button et al., 1999). Clearly, the issue of environmental degradation is not new in human history. Plato in his Kritias was complaining about human activity that had turned the landscape of Attica into a skeleton and a wasteland. And ancient cities also demonstrated a clear awareness of the risks of environmental quality decline. We also know about environmental regulation in medieval European cities that aimed to control the use of coal burning or the noise annoyance caused by horse-drawn carriages. And the early stage of the industrial revolution demonstrated an abundance of urban environmental quality degradation and related policy concern. But in our era the size and the intensity of resource use and of related environmental decay have taken such massive forms that the stability and sustainability of many ecosystems —both locally and globally —is threatened. This has stimulated the launching of the concept of sus-
0921-8009/02/$ - see front matter © 2002 Elsevier Science B.V. All rights reserved. PII: S 0 9 2 1 - 8 0 0 9 ( 0 1 ) 0 0 2 5 1 - 8
152
R. Capello, P. Nijkamp / Ecological Economics 40 (2002) 151–155
tainable development in research and policy making at the end of the 1980s as well as the international research interest in biodiversity loss and climate change risks during the 1990s and beyond. In a few decades time, an overwhelming amount of research effort and research findings on environmental and resource issues can be observed. Environmental and resource economics has generated new insights into environmental policy design, natural resource management, transboundary pollution issues, and international agreements and policy co-ordination. Both theoretical and empirical knowledge has been generated at a surprisingly rapid pace. This also applies at a lower scale to urban environmental issues. Clearly, environmental issues have a surprising diversity, ranging from local to global levels. After the avalanche of interest in global environmental issues (see e.g. the Bruntland Report or the Report of the World Commission on Environment and Development WCED, 1987), the awareness has grown that many environmental problems have a local origin, not that global environmental decay often manifests itself at a local level. Thus, there is a simultaneous need for local action and global reflection. Consequently, cities may act as focal points for creative environmental strategies (see also Stanners and Bourdeau, 1995). There are convincing reasons why a well focused environmental policy at the urban level is a valuable activity in the framework of the worldwide mission for improving environmental quality. First, there is the obvious reason that most production, consumption and transportation activities in a country take place in urban areas. It is noteworthy that in most countries the level of urbanisation is still increasing, not only in prosperous regions but also in less favoured regions. Thus, a clear focus on urban quality of life may enhance the effectiveness of resource and environmental strategies in many countries. Next, decentralisation of environmental and resource policy has become a major device in current policy-making in most Western countries. The city is, of course, a natural institutional decision unit in this context, as it covers a well-focused study area without running the risk of a heterogeneous pol-
icy structure with many horizontally organised planning agencies (and related competence questions). Thus, the involvement of one identifiable decision-making agency at the urban level is of major importance and may enhance the institutional effectiveness of environmental and energy planning. A related obvious advantage may be direct local involvement, based on a bottom-up strategy for new environmental management and energy saving programmes (for instance, in the case of district heating). This may increase the support of the general public for changes in resource use, consumption or life styles. Finally, in terms of efficiency of data gathering and/or availability, the city is usually a more suitable statistical unit providing systematic data sets on environmental, energy and socio-economic indicators. Clearly, environmental problems are not an exclusive subject matter for economic analysis. They are issues that call for a multidisciplinary approach, ranging from economics to urban planning, and from biology to ecology. There are, in fact, many ways for a simultaneous analytical treatment of economics and environment. Since the 1960s a great many attempts have been made to link the economy to the ecology (Costanza et al., 1997). An important contribution to the integration of economics and ecology began simply with a reflection on the principles of the materials balance for resources (extracted or collected, transformed, consumed and emitted) and on the need to take account of an economic viewpoint of such processes (Ayres et al., 1999). Several attempts have also been made to build economic and social accounting systems that could incorporate the measurement of economic welfare and performance together with the measurement of environmental indicators and performances. The integration of economics with ecology has also been approached from the viewpoint of landuse where economic and ecological processes have the most disruptive effects— and of urban environments. In addition, the interaction between economics and ecology has been dealt with for situations with global risks and uncertainties (Turner et al., 1999). All such contributions have also a great relevance for urban sustainability
R. Capello, P. Nijkamp / Ecological Economics 40 (2002) 151–155
issues in terms of both research and policy making. The aim of this special issue of Ecological Economics on ‘The Economics of Urban Sustainability’ is not to provide a collection of works covering critical aspects of urban environmental economics. Its aim is rather to present some refreshing contributions to the subject, in order to provide new insights into some of the most fascinating and prominent issues in urban sustainability. The special issue is organised around five papers. Despite their differences in terms of scope, approaches and issues treated, the first three papers have a common element, centring around urban size and urban dynamics. The first paper, by Verhoef and Nijkamp, offers a theory on urban sustainability from the perspective of externalities. The authors develop a general spatial equilibrium model of a monocentric city, in which two types of externalities occur. On the one hand, pollution in the industrial centre leads to a spatially differentiated deterioration of the environmental quality in the residential area. On the other hand, the existence of the city is explained by agglomeration economies, represented as simple Marshallian external benefits in production. The resulting urban patterns may be diverse and complex. The authors investigate free-market versus first-best and second-best optimal spatial equilibria, and conclude that the pursuit of environmental goals may sometimes come at the expense of reduced agglomeration economies, but may actually sometimes also stimulate these economies. The second paper, by Capello and Faggian, starts from the consideration that, since urban size plays an important role in the possibility of shaping the quality of urban living conditions, the study of urban dynamics and of its determinants is vital to ensure environmental quality in the city. The awareness of the existence of cyclical patterns in urban dynamics is useful for the formulation of environmental policies enabling a steady state equilibrium to be reached in terms of sustainability by flattening out the cyclical waves. A number of quantitative models for the interpretation of urban growth is also provided; these models are related to the well-known ecological prey-preda-
153
tor model of Lotka–Volterra, and provide a useful interpretative framework for studying territorial phenomena characterised by strong feed-back mechanisms. Recently, a new and simple model linking per-capita income and urban rents has been developed as a possible interpretative model of urban growth which is characterised by two main advantages: (a) its capacity to overcome some of the limits of the previous preypredator models, such as the necessity to apply the concept of an urban carrying capacity; (b) its purely economic foundation. The paper presents this model and its logic, and provides an empirical analysis of the model, based on the Italian case. An econometric exercise is presented on the relationship between urban population growth and urban rent, based on a database of 95 Italian cities during the period 1963–1996, while allowing for feedback mechanisms between the two variables. This paper presents a first attempt to offer an estimate of this prey-predator model based on real world data. The third paper, by Camagni, Gibelli and Rigamonti, deals with the problem of urban development, and it stresses in particular the importance of the environmental or social costs of urban form, which is increasingly attracting attention in spatial policy. However, the scientific debate in this field is often marked by prejudices and abstract visions; empirical analyses are rather rare. The present study aims at establishing, in the context of a study of the metropolitan area of Milan, whether different patterns of urban expansion may be associated with specific environmental costs— in particular, for land consumption and mobility generation. Different typologies of urban expansion are defined, and an impact index weighting differently journey-to-work trips with reference to mode and time length is built at the municipality level. The statistical analysis confirms the expected ‘wasteful’ character of sprawling development patterns in terms of land consumption, though suggesting that recent urban development is becoming relatively ‘virtuous’ with respect to the past. With reference to the mobility generated, higher environmental impacts were proven to be associated with low densities, sprawling development, more recent urbanisation
154
R. Capello, P. Nijkamp / Ecological Economics 40 (2002) 151–155
processes and residential specialisation of the single municipalities. Public transport seems to be strongly influenced, both in terms of efficiency and competitiveness, by the structural organisation of an urban area: the more dispersed and less structured the development, the lower its level of efficiency and competitiveness and consequently its share of the mobility market. On the contrary, travel times for private transport appear to be weakly correlated with the urban dimension or density in terms of recent housing development, indicating the emergence of new models of lifestyle and mobility that are very different from those of the past. The fourth paper, by Button, deals with the largely debated issue on urban sustainability indicators. It starts from the consideration that cities are complex and dynamic entities. They are also nodes in spatial economic, social and political geographical networks. Furthermore, they are focal points for many of the concerns that characterise current debates about sustainable development. The aim of the paper is to focus on the local environmental effects of urbanisation and to consider ways in which they may be effectively treated within the confines of an isolated city context and more generally when urban areas are seen as part of a wider economic system. Particular attention is focused on information systems of all types and on feedback mechanisms (including automatic mechanisms) which help, in particular, the integration of economic and environmental considerations at the urban level. The underlying question posed by the author is that of deciding on the role that urban indicators (both economic and environmental) can play in assisting to improve the management of cities. The points made are general and conceptual rather than being of a quantitative and empirical nature. The paper does not aim to develop an alternative framework for the existing indicators, which various urban actors use in their efforts to manage urban affairs, but offers a state-of-the-art overview. The fifth paper, by Nijkamp, Rodenburg and Wagtendonk, deals with a critical issue in the context of urban quality of life, that of urban soil pollution. In sustainable city planning, one can
observe in recent years an increasing policy interest in urban environmental quality management in relation to land use. The potential for sustainable land use solutions in urban areas is often severely hampered by the existence of unacceptably high levels of soil pollution. The paper aims to identify the critical success factors for an effective clean-up policy for these areas. After a review of issues, backgrounds and prospects, the paper attempts to offer a qualitative impact assessment model, which encapsulates an expert system for brownfield development in relation to clean-up targets for polluted sites. Next, a comparative case study approach to various soil pollution cases in The Netherlands is carried out to test the feasibility of the above-mentioned analytical framework. A subsequent step consists of the use of modern meta-analytic techniques for comparative research and research synthesis in order to trace the drivers of failure or success in brownfield development policy in urban areas. The particular method employed here, rough set analysis, appears to be able to identify the conditions— in terms of packages of drivers— under which such urban policies are likely to be successful. All five contributions call for urban environmental policy in line with what has recently been suggested at various international fora. The 1992 UN conference on Environment and Development (the Rio Conference) pinpointed several strategic policy needs and resulted in Agenda 21 which claimed ‘‘Human beings are at the centre of concern for sustainable de6elopment. They are entitled to a healthy and producti6e life in harmony with nature’’. It was increasingly realised, however, that such an ambitious goal should be fulfilled in close co-operation with local stakeholders. This awareness led in 1997 to the formulation of the worldwide Local Agenda 21 where a plea is made for dedicated local actions that are needed to combine a reduction of environmental decay with an improvement of local socio-economic conditions in both industrialised and Third World countries. The European version of Local Agenda 21 is coined the Charter of European Cities and Towns Towards Sustainability. It regards sustainability as a creative, balance-seeking process extending
R. Capello, P. Nijkamp / Ecological Economics 40 (2002) 151–155
into all areas of local decision-making. It states that sustainable development helps cities and towns to base living patterns on the carrying capacity of nature, while seeking to achieve social justice, sustainable economies and environmental sustainability (see also Mega, 1999). The implementation of such strategies needs, of course, a proper use of policy and achievement indicators. This is also recognised in Agenda 21, where it is claimed that: ‘‘Indicators of sustainable de6elopment need to be de6eloped to pro6ide solid bases for decision making at all le6els and to contribute to a self-regulating sustainability of integrated en6ironment and de6elopment systems’’. Such indicators would be measurable, comparable, transferable, informative, signalling (e.g. early warning systems) and acceptable for policy choices (see Button’s contribution in this volume). Ideally, policy choices should be based on realistic information, while the relevant indicators would have to be geared towards urban sustainability policies. It should be recognised that the tasks posed on the shoulders of cities are immense, but it ought to be stressed as well that cities are in a unique position to develop proper sustainability strategies through the agglomeration advantages originating from their geographical synergy. A major challenge to modern cities is the need to ensure economic, social and ecological sustainability now and in the medium and long-term future. Economies of scale may erode the quality of the urban living environment and the social stability base of the cities so that a well-tuned effort has to be made to reconcile environmental demands with economic goals of the city (see Orishimo, 1982). This task is once more important in a dynamic network environment instigated by the ICT sector, through which a trend toward mega-cities may emerge (see Brotchie et al., 1999). Since cities worldwide go through a process of
155
rapid change, the question is how to ensure continuity in change; in other words, how to use the valuable elements from the past (e.g. culture, science, entrepreneurial spirit) as the basis for a promising future. This resilience behaviour does not come about automatically, but certainly requires an effective sustainable city policy. In doing so, economic (market-based) incentives are needed in order to increase efficiency and to cope with the negative factors of modern city life. Failure to develop an effective balanced urban development policy will reinforce urban sprawl and will highlight inner city problems to a much larger area, thus intensifying negative urban externalities.
References Ayres, R.U., Button, K., Nijkamp, P. (Eds.), 1999. Global Aspects of the Environment, vol. 1 and 2. Edward Elgar, Cheltenham, UK. Brotchie, J., Newton, P., Hall, P., Dickey, J. (Eds.), 1999. East – West Perspective on 21st Century Urban Development. Ashgate, Alderhot, UK. Costanza, R., 1997. In: Costanza, R., Perrings, C., Cleveland, C.J. (Eds.), The Development of Ecological Economics. Edward Elgar, Cheltenham, UK. Mega, V., 1999. Planning the Civilisation of Sustainability, International Conference on ‘Sustainable Development and Spatial Planning in the European Territory’, Athens, May 1999. Orishimo, I., 1982. Urbanisation and Environmental Quality. Kluwer, Dordrecht. Stanners, D., Bourdeau, P. (Eds.), 1995. Europe’s Environment (The Dobrı`s Report). European Environmental Agency, Brussels. Tietenberg, T., 1995. Environmental and Natural Resource Economics. Harper Collins, New York. Turner, R.K., Button, K., Nijkamp, P. (Eds.), 1999. Ecosystems and Nature: Economics, Science and Policy. Edward Elgar, Cheltenham. WCED, 1987. Our Common Future, Oxford University Press, New York.
SPECIAL SECTION: ECONOMICS OF URBAN SUSTAINABILITY
In search of sustainable human settlements Prefatory remarks Roberta Capello a,*, Peter Nijkamp b b
a Department of Economics, Politecnico di Milano, Piazza Leonardo da Vinci 32, 20133 Milan, Italy Department of Spatial Economics, Free Uni6ersity, De Boelelaan 1105, 1081 HV Amsterdam, The Netherlands
Needs satisfaction under a regime of scarce goods is the pivotal interest of economics. The last part of the 20th century has shown the emergence of a new type of scarcity, viz. a healthy environment to work and live in. This new scarcity is reflected in the decline in air, water and soil quality as well as in a general decline in biodiversity. The unpriced nature of many environmental goods makes it difficult to incorporate the environment in the normal calculation schemes of rational market behaviour (see Tietenberg, 1995). It is noteworthy that environmental externalities are no longer esoteric events in a normal market system; they have even become a usual feature. The worldwide decay in environmental quality conditions and the gradual depletion of natural resources has become a dominant theme for research and public policy in the last part of the 20th century. The global interest in environmental matters is partly caused by the increased pressure that a mounting population and increased production exert on the earth’s natural resource base. In addition, as personal incomes rise and leisure time becomes more freely available in the developed world, concern with * Corresponding author. E-mail address: [email protected] (R. Capello).
more immediate human needs has been accompanied by an interest in preservation and conservation for future generations and in other regions of our world. We observe an increasing interest in quality —next to quantity —as an important constituent of individual and collective welfare in which the environment assumes a prominent position on the Maslow needs hierarchy (see also Button et al., 1999). Clearly, the issue of environmental degradation is not new in human history. Plato in his Kritias was complaining about human activity that had turned the landscape of Attica into a skeleton and a wasteland. And ancient cities also demonstrated a clear awareness of the risks of environmental quality decline. We also know about environmental regulation in medieval European cities that aimed to control the use of coal burning or the noise annoyance caused by horse-drawn carriages. And the early stage of the industrial revolution demonstrated an abundance of urban environmental quality degradation and related policy concern. But in our era the size and the intensity of resource use and of related environmental decay have taken such massive forms that the stability and sustainability of many ecosystems —both locally and globally —is threatened. This has stimulated the launching of the concept of sus-
0921-8009/02/$ - see front matter © 2002 Elsevier Science B.V. All rights reserved. PII: S 0 9 2 1 - 8 0 0 9 ( 0 1 ) 0 0 2 5 1 - 8
152
R. Capello, P. Nijkamp / Ecological Economics 40 (2002) 151–155
tainable development in research and policy making at the end of the 1980s as well as the international research interest in biodiversity loss and climate change risks during the 1990s and beyond. In a few decades time, an overwhelming amount of research effort and research findings on environmental and resource issues can be observed. Environmental and resource economics has generated new insights into environmental policy design, natural resource management, transboundary pollution issues, and international agreements and policy co-ordination. Both theoretical and empirical knowledge has been generated at a surprisingly rapid pace. This also applies at a lower scale to urban environmental issues. Clearly, environmental issues have a surprising diversity, ranging from local to global levels. After the avalanche of interest in global environmental issues (see e.g. the Bruntland Report or the Report of the World Commission on Environment and Development WCED, 1987), the awareness has grown that many environmental problems have a local origin, not that global environmental decay often manifests itself at a local level. Thus, there is a simultaneous need for local action and global reflection. Consequently, cities may act as focal points for creative environmental strategies (see also Stanners and Bourdeau, 1995). There are convincing reasons why a well focused environmental policy at the urban level is a valuable activity in the framework of the worldwide mission for improving environmental quality. First, there is the obvious reason that most production, consumption and transportation activities in a country take place in urban areas. It is noteworthy that in most countries the level of urbanisation is still increasing, not only in prosperous regions but also in less favoured regions. Thus, a clear focus on urban quality of life may enhance the effectiveness of resource and environmental strategies in many countries. Next, decentralisation of environmental and resource policy has become a major device in current policy-making in most Western countries. The city is, of course, a natural institutional decision unit in this context, as it covers a well-focused study area without running the risk of a heterogeneous pol-
icy structure with many horizontally organised planning agencies (and related competence questions). Thus, the involvement of one identifiable decision-making agency at the urban level is of major importance and may enhance the institutional effectiveness of environmental and energy planning. A related obvious advantage may be direct local involvement, based on a bottom-up strategy for new environmental management and energy saving programmes (for instance, in the case of district heating). This may increase the support of the general public for changes in resource use, consumption or life styles. Finally, in terms of efficiency of data gathering and/or availability, the city is usually a more suitable statistical unit providing systematic data sets on environmental, energy and socio-economic indicators. Clearly, environmental problems are not an exclusive subject matter for economic analysis. They are issues that call for a multidisciplinary approach, ranging from economics to urban planning, and from biology to ecology. There are, in fact, many ways for a simultaneous analytical treatment of economics and environment. Since the 1960s a great many attempts have been made to link the economy to the ecology (Costanza et al., 1997). An important contribution to the integration of economics and ecology began simply with a reflection on the principles of the materials balance for resources (extracted or collected, transformed, consumed and emitted) and on the need to take account of an economic viewpoint of such processes (Ayres et al., 1999). Several attempts have also been made to build economic and social accounting systems that could incorporate the measurement of economic welfare and performance together with the measurement of environmental indicators and performances. The integration of economics with ecology has also been approached from the viewpoint of landuse where economic and ecological processes have the most disruptive effects— and of urban environments. In addition, the interaction between economics and ecology has been dealt with for situations with global risks and uncertainties (Turner et al., 1999). All such contributions have also a great relevance for urban sustainability
R. Capello, P. Nijkamp / Ecological Economics 40 (2002) 151–155
issues in terms of both research and policy making. The aim of this special issue of Ecological Economics on ‘The Economics of Urban Sustainability’ is not to provide a collection of works covering critical aspects of urban environmental economics. Its aim is rather to present some refreshing contributions to the subject, in order to provide new insights into some of the most fascinating and prominent issues in urban sustainability. The special issue is organised around five papers. Despite their differences in terms of scope, approaches and issues treated, the first three papers have a common element, centring around urban size and urban dynamics. The first paper, by Verhoef and Nijkamp, offers a theory on urban sustainability from the perspective of externalities. The authors develop a general spatial equilibrium model of a monocentric city, in which two types of externalities occur. On the one hand, pollution in the industrial centre leads to a spatially differentiated deterioration of the environmental quality in the residential area. On the other hand, the existence of the city is explained by agglomeration economies, represented as simple Marshallian external benefits in production. The resulting urban patterns may be diverse and complex. The authors investigate free-market versus first-best and second-best optimal spatial equilibria, and conclude that the pursuit of environmental goals may sometimes come at the expense of reduced agglomeration economies, but may actually sometimes also stimulate these economies. The second paper, by Capello and Faggian, starts from the consideration that, since urban size plays an important role in the possibility of shaping the quality of urban living conditions, the study of urban dynamics and of its determinants is vital to ensure environmental quality in the city. The awareness of the existence of cyclical patterns in urban dynamics is useful for the formulation of environmental policies enabling a steady state equilibrium to be reached in terms of sustainability by flattening out the cyclical waves. A number of quantitative models for the interpretation of urban growth is also provided; these models are related to the well-known ecological prey-preda-
153
tor model of Lotka–Volterra, and provide a useful interpretative framework for studying territorial phenomena characterised by strong feed-back mechanisms. Recently, a new and simple model linking per-capita income and urban rents has been developed as a possible interpretative model of urban growth which is characterised by two main advantages: (a) its capacity to overcome some of the limits of the previous preypredator models, such as the necessity to apply the concept of an urban carrying capacity; (b) its purely economic foundation. The paper presents this model and its logic, and provides an empirical analysis of the model, based on the Italian case. An econometric exercise is presented on the relationship between urban population growth and urban rent, based on a database of 95 Italian cities during the period 1963–1996, while allowing for feedback mechanisms between the two variables. This paper presents a first attempt to offer an estimate of this prey-predator model based on real world data. The third paper, by Camagni, Gibelli and Rigamonti, deals with the problem of urban development, and it stresses in particular the importance of the environmental or social costs of urban form, which is increasingly attracting attention in spatial policy. However, the scientific debate in this field is often marked by prejudices and abstract visions; empirical analyses are rather rare. The present study aims at establishing, in the context of a study of the metropolitan area of Milan, whether different patterns of urban expansion may be associated with specific environmental costs— in particular, for land consumption and mobility generation. Different typologies of urban expansion are defined, and an impact index weighting differently journey-to-work trips with reference to mode and time length is built at the municipality level. The statistical analysis confirms the expected ‘wasteful’ character of sprawling development patterns in terms of land consumption, though suggesting that recent urban development is becoming relatively ‘virtuous’ with respect to the past. With reference to the mobility generated, higher environmental impacts were proven to be associated with low densities, sprawling development, more recent urbanisation
154
R. Capello, P. Nijkamp / Ecological Economics 40 (2002) 151–155
processes and residential specialisation of the single municipalities. Public transport seems to be strongly influenced, both in terms of efficiency and competitiveness, by the structural organisation of an urban area: the more dispersed and less structured the development, the lower its level of efficiency and competitiveness and consequently its share of the mobility market. On the contrary, travel times for private transport appear to be weakly correlated with the urban dimension or density in terms of recent housing development, indicating the emergence of new models of lifestyle and mobility that are very different from those of the past. The fourth paper, by Button, deals with the largely debated issue on urban sustainability indicators. It starts from the consideration that cities are complex and dynamic entities. They are also nodes in spatial economic, social and political geographical networks. Furthermore, they are focal points for many of the concerns that characterise current debates about sustainable development. The aim of the paper is to focus on the local environmental effects of urbanisation and to consider ways in which they may be effectively treated within the confines of an isolated city context and more generally when urban areas are seen as part of a wider economic system. Particular attention is focused on information systems of all types and on feedback mechanisms (including automatic mechanisms) which help, in particular, the integration of economic and environmental considerations at the urban level. The underlying question posed by the author is that of deciding on the role that urban indicators (both economic and environmental) can play in assisting to improve the management of cities. The points made are general and conceptual rather than being of a quantitative and empirical nature. The paper does not aim to develop an alternative framework for the existing indicators, which various urban actors use in their efforts to manage urban affairs, but offers a state-of-the-art overview. The fifth paper, by Nijkamp, Rodenburg and Wagtendonk, deals with a critical issue in the context of urban quality of life, that of urban soil pollution. In sustainable city planning, one can
observe in recent years an increasing policy interest in urban environmental quality management in relation to land use. The potential for sustainable land use solutions in urban areas is often severely hampered by the existence of unacceptably high levels of soil pollution. The paper aims to identify the critical success factors for an effective clean-up policy for these areas. After a review of issues, backgrounds and prospects, the paper attempts to offer a qualitative impact assessment model, which encapsulates an expert system for brownfield development in relation to clean-up targets for polluted sites. Next, a comparative case study approach to various soil pollution cases in The Netherlands is carried out to test the feasibility of the above-mentioned analytical framework. A subsequent step consists of the use of modern meta-analytic techniques for comparative research and research synthesis in order to trace the drivers of failure or success in brownfield development policy in urban areas. The particular method employed here, rough set analysis, appears to be able to identify the conditions— in terms of packages of drivers— under which such urban policies are likely to be successful. All five contributions call for urban environmental policy in line with what has recently been suggested at various international fora. The 1992 UN conference on Environment and Development (the Rio Conference) pinpointed several strategic policy needs and resulted in Agenda 21 which claimed ‘‘Human beings are at the centre of concern for sustainable de6elopment. They are entitled to a healthy and producti6e life in harmony with nature’’. It was increasingly realised, however, that such an ambitious goal should be fulfilled in close co-operation with local stakeholders. This awareness led in 1997 to the formulation of the worldwide Local Agenda 21 where a plea is made for dedicated local actions that are needed to combine a reduction of environmental decay with an improvement of local socio-economic conditions in both industrialised and Third World countries. The European version of Local Agenda 21 is coined the Charter of European Cities and Towns Towards Sustainability. It regards sustainability as a creative, balance-seeking process extending
R. Capello, P. Nijkamp / Ecological Economics 40 (2002) 151–155
into all areas of local decision-making. It states that sustainable development helps cities and towns to base living patterns on the carrying capacity of nature, while seeking to achieve social justice, sustainable economies and environmental sustainability (see also Mega, 1999). The implementation of such strategies needs, of course, a proper use of policy and achievement indicators. This is also recognised in Agenda 21, where it is claimed that: ‘‘Indicators of sustainable de6elopment need to be de6eloped to pro6ide solid bases for decision making at all le6els and to contribute to a self-regulating sustainability of integrated en6ironment and de6elopment systems’’. Such indicators would be measurable, comparable, transferable, informative, signalling (e.g. early warning systems) and acceptable for policy choices (see Button’s contribution in this volume). Ideally, policy choices should be based on realistic information, while the relevant indicators would have to be geared towards urban sustainability policies. It should be recognised that the tasks posed on the shoulders of cities are immense, but it ought to be stressed as well that cities are in a unique position to develop proper sustainability strategies through the agglomeration advantages originating from their geographical synergy. A major challenge to modern cities is the need to ensure economic, social and ecological sustainability now and in the medium and long-term future. Economies of scale may erode the quality of the urban living environment and the social stability base of the cities so that a well-tuned effort has to be made to reconcile environmental demands with economic goals of the city (see Orishimo, 1982). This task is once more important in a dynamic network environment instigated by the ICT sector, through which a trend toward mega-cities may emerge (see Brotchie et al., 1999). Since cities worldwide go through a process of
155
rapid change, the question is how to ensure continuity in change; in other words, how to use the valuable elements from the past (e.g. culture, science, entrepreneurial spirit) as the basis for a promising future. This resilience behaviour does not come about automatically, but certainly requires an effective sustainable city policy. In doing so, economic (market-based) incentives are needed in order to increase efficiency and to cope with the negative factors of modern city life. Failure to develop an effective balanced urban development policy will reinforce urban sprawl and will highlight inner city problems to a much larger area, thus intensifying negative urban externalities.
References Ayres, R.U., Button, K., Nijkamp, P. (Eds.), 1999. Global Aspects of the Environment, vol. 1 and 2. Edward Elgar, Cheltenham, UK. Brotchie, J., Newton, P., Hall, P., Dickey, J. (Eds.), 1999. East – West Perspective on 21st Century Urban Development. Ashgate, Alderhot, UK. Costanza, R., 1997. In: Costanza, R., Perrings, C., Cleveland, C.J. (Eds.), The Development of Ecological Economics. Edward Elgar, Cheltenham, UK. Mega, V., 1999. Planning the Civilisation of Sustainability, International Conference on ‘Sustainable Development and Spatial Planning in the European Territory’, Athens, May 1999. Orishimo, I., 1982. Urbanisation and Environmental Quality. Kluwer, Dordrecht. Stanners, D., Bourdeau, P. (Eds.), 1995. Europe’s Environment (The Dobrı`s Report). European Environmental Agency, Brussels. Tietenberg, T., 1995. Environmental and Natural Resource Economics. Harper Collins, New York. Turner, R.K., Button, K., Nijkamp, P. (Eds.), 1999. Ecosystems and Nature: Economics, Science and Policy. Edward Elgar, Cheltenham. WCED, 1987. Our Common Future, Oxford University Press, New York.