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Dr. Tee L. Guidotti



Assessing the Health of Urban Ecosystems

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Dr. Tee L. Guidotti, Chair
Dept. of Environmental and Occupational Health
School of Public Health and Health Services


Sustainable development is a widely-discussed alternative to currently unsustainable economic development patterns. It is all the more attractive because it may be cast in terms compatible with the market economy. However, there must be a social dimension to the concept, a vision, for it to become a viable alternative to unrestrained economic growth. The Earth is no longer a self-regulating planetary system. Its future will depend on human action and the continuation of natural ecosystems will be achieved because people want them to be preserved. Acceptance of sustainable development by society may depend on cultural values and even spiritual notions about the relationship of humankind to the Earth. This is why the otherwise quasi-religious concepts often expressed in the environmental movement, such as the Gaia hypothesis, have value as metaphor even if they do not necessarily express literal fact. Sustainable development is often described in terms that suggest a static, less technology-dependent, and culturally more homogeous regionalized society. However, sustainable development cannot be stagnation. People will not accept a view of sustainable development that recreates a technologically more advanced version of a basic peasant society, especially if they have only recently developed economically. For societies to accept sustainable development and to continue to grow within, the new way of living must accept cultural diversity, encourage individual expression, allow social change, offer opportunity, and examine values. There must be ways to permit opportunity and growth without ecological compromise. Achieving sustainable development may therefore be linked with policies emphasizing community, the value of information, originality in ideas, and the arts.

There is no doubt that the issue of global ecological changes is one of the most potent in the movement toward ecological sustainability and economic reconstruction. It may even represent the next great challenge to the adaptability of the market economy. However, sustainable development needs to be thought through beyond its ecological and economic dimensions. It needs, in short, a vision.

Sustainable development is a concept critical to understanding proposals for solutions to the problem of large-scale ecological degradation and resource depletion in the context of personal freedom and the adaptability of markets. Briefly, the concept, as elaborated in the Brundtland report, involves establishing an economic structure that ideally consumes only as much as the natural environment produces and emits only as much as the natural environment can absorb. This is accomplished by reducing consumption and the scale of economic development, recycling materials, and reusing as much product as possible. This economic structure is sustainable in the sense that it can be sustained from one generation to another. It would differ from traditional peasant societies, which have been the only sustainable economic systems in the past to support large populations through many centuries, in being much more efficient in the use of resources, innovative, and based to a large extent on information management. There is a cultural dimension to moving toward this type of society, however. To accommodate and manage a sustainable economic system, the social structure would also have to change. Large-scale urban centres would be nonsustainable; traditional values that promote stability may be more supportive of sustainability than cosmopolitan, urban, entrepreneurial values. There is a question of whether the environmental heterogeneity and social pluralism of modern urban society, which many people feel tends to promote creativity (and also conflict) could be accommodated in such a system. It is often assumed that most communities under such a regime would be small, resource-efficient, and directly linked (either economically or through information on the state of its base) to a resource base in a way that would maintain some control over the exploitation of resources, a reversal of current demographic patterns.

Once the implications of sustainable development are traced through their social ramifications, it becomes clear that nothing less than a thorough restructuring of society would accommodate a sustainable economic structure. Issues of equity and community control over these resources and decision-making with respect to their distribution obviously arise. The concept of sustainable development is closely linked, in the minds of many, with that of community empowerment and a host of related issues related to social justice and cultural expression. There are other, less direct links that take the form of doctrines of ethical stewardship of resources, sharing the bounty of the Earth with all mankind, perceptions of the Earth as a veritable being or "Gaia" analogous to a mother to us all and not to be injured, making the world better for future generations, and many others.

An Alternative View

The Earth is no longer a self-correcting natural system. The planet now requires human intervention to stabilize its most basic functions and to reconstruct the degraded systems on which life ultimately depends. Even the remaining wild areas of the world, unexploited by humankind, are in almost every case preserved by human action, in the form of reserves or juridical restraint on allowable activities.

The Earth is no longer, if it ever was, a self-regulating planetary system returning to balance by the actions of its intrinsic processes of control. Rather, human activity has destabilized the planet to the point that the romantic "Gaia hypothesis", if it were ever true, now belongs to the past. It could be said that the Earth has always been a dynamic system, ever-changing in the evolution of life and the response to physical forces in the solar system, but over relatively short periods of its history, on the order of millions of years, it has sustained itself within a relatively fixed pattern of climate and life zones. What is different today is that the pace of change, even in the shortest of planetary time frames, has been accelerated by human activity, intentional intervention for the benefit of one dominant species. The planet cannot regulate itself reliably in the face of such rapid change. For better or for worse, human beings have so altered the planetary structure that they must now take even greater control of the situation to prevent further destabilization. This means assuming responsibility for restoring, not just preserving, ecosystems and other lost elements of the planetary fabric.

Conversely, the manifestations of ecological problems are all fundamentally interrelated and inseparable from societal values:

1. Global ecological changes (global warming, ozone depletion, acid deposition, resource depletion), as a consequence of overutilization of resources and overproduction of product and byproduct;

2. Population growth, migration, and refugee flight, increasing local and global pressures with an amplified effect where technology is most extractive and inefficient (polluting);

3. Economic development, energy demand, and generational expectations for standard of living which drive the economic system to provide more materially at the expense of resources and environmental stability;

4. Poverty, the culture of dependency, and the redistribution of resources, feeding the inequities that drive demand and make short-term expediency easier than long-term resource conservation;

5. Urbanization, the concentration of resources and economic activity, and the impact of human settlements on a large scale, which may have the effect of regionally concentrating the adverse effects of human activity but may also provide opportunities for more efficient resource utilization;

6. Cultural views of the world and the degree to which world-view dictates the vision of what is and is not possible politically and what actions are more or less likely to succeed in environmental reconstruction and management.

The material culture of society, expressed in economics, and ethical systems are inextricably intertwined in issues of equity and respect for the natural earth. Because treating the environment respectfully is an effective strategy for sustaining the yield of renewable resources, it is not surprising that most indigenous cultures incorporate religious or philosophical beliefs to the effect that the Earth is a provider, a sentient being, and an ancestor. To act in ways that do no harm to the planet is a highly adaptive and desirable code of behaviour when a relatively static population depends on a sustained yield of food and fibre. In the absence of an articulated theory of resources and material distribution, a traditional society incorporates these adaptive biocentric ways of thinking into religious belief systems, including the concept of Earth (or Gaea, Gaia, or Erde) as nurturing Mother. In such a society, sustainable development would mean (if it were meaningful as a separate thematic strand in the culture) sustaining the Earth as well as all its creatures, including its human communities.

A society based on growth, however, separates from this value in the optimistic belief that technological ingenuity and artificial constraints (such as pricing) can protect resources from becoming ultimately inaccessible for human use; since the values are recast in humanistic and anthropocentric terms, utility for humankind becomes the dominant reason for conserving resources. In this view, sustainable development is mostly about sustaining yield indefinitely and conserving resources systematically for future exploitation.

There is at present a conflict within society over which worldview will prevail. The "human utility" or "best use" view is much more compatible with the presently dominant growth-oriented economically motivated society. Even the notion of resource conservation fits well into this context because it can be translated into serving future markets. The "biocentric" or "highest use" worldview is paradoxically much more traditional but discordant with present dominant values; one strategy for replacing the dominant values is to appeal to traditional wisdom, intuitive understanding, and quasi-religious symbolism. The present-day environmental movement borrows heavily on these traditional values in an effort to recreate a biocentric ethic as the dominant worldview. The biocentric worldview is an essential tenet of the vanguard of the environmental movement, the proponents of "deep ecology". An example is the promotion of the "Gaia hypothesis". Besides having merit as a literal construct the hypothesis is useful as a means of personalizing responsibility for environmental damage. One cannot "hurt" an inanimate object, although it can be damaged for use for a given purpose; one can "hurt" a living being, even of planetary dimensions.

It is not clear that the biocentric worldview will completely replace the dominant anthropocentric worldview in the move toward some form of sustainable development. There is the obvious problem of inertia involved in changing all social institutions more or less simultaneously. There is also the nagging problem that alternative, stable and biocentric social orders do not necessarily appear very attractive to most of the world's citizens, particularly those only now emerging from traditional village societies. For all of its enormous disadvantages, contemporary urban culture has great advantages in terms of social and material efficiency, individual opportunity, cultural expression, and ingenuity. A return to historic Western models means to some a return to the Middle Ages and earlier (an impression heightened by the Druidic references in much of the literature of "deep ecology"), with the risk of social stagnation as a price for material stability and ecological responsibility. To societies only now emerging from predominantly peasant and village systems of social organization, the prospect of a return must seem almost chilling. To date, deep ecology has been more successful in articulating a vision of harmonious coexistence with nature on a vastly reduced scale of society than in articulating an alternative vision of a dynamic society in which intellectual and information growth replaces material and economic growth. Perhaps this will come in due time.

Implications for Society and Sustainable Development

To be fair, it is not clear that in the future contemporary urban society will maintain the historic level of opportunity and cultural expression associated with urban culture, either. Umberto Eco speaks convincingly of a return to the Middle Ages in a different sense, in concepts of progress, in attitude and cultural forms. The standardization of commerce and architecture, reductions in employment opportunities, and the obliteration of regional differences from popular culture that would accompany a retrogressive form of sustainable development may be seen by many as resulting in a much more homogenous, simplified, and impoverished form of urban life. What is more likely to occur is a synthesis, in the form of an adoption of sustainable development as a general economic basis, with some social tolerance of limited short-term ecological destruction as long as reconstruction is generally restoring the quality of the environment overall. In other words, if the world seems to be well on its way to restoring equilibrium, most people will probably accept limitations on opportunity in their individual lives and would at the same time tolerate limited environmental exploitation (such as mining) if considerable ends (a significant enhancement in human utility) appeared to justify modest means (limited impact followed by reclamation but nonetheless inevitably some adverse effects). Whether this synthesis is stable or transitional depends in part on whether it is seen by people as an improvement or regression in social terms and whether technology can mitigate environmental impacts to an acceptable degree.

Technology, of course, plays a major role in causing many of these environmental problems. In a sense, especially if agricultural technology is considered, technology was necessary for humankind to achieve unsustainable development. It is popular to speak of problems for which there are no technical solutions and the need for a more fundamental change in society. It is not surprising that there should exist problems with technology, because technology is inherently a systematic balancing of forces and interconversion of energy (mechanical, electrical, chemical, etc.) to achieve a desired goal. As such, technological processes are always subject to inefficiencies, since the conversion of energy can never be 100% (indeed in most technological applications it is seldom as high as 40%). There will always be material and energy waste and continual tradeoffs between desirable and undesirable results. Forces that balance one another in one way do not necessarily balance in another desirable way: cars with more power produce more air pollution, increased production efficiency may cause unemployment, and the siting of a pulp and paper plant may not be appropriate ecologically in spite of economic advantages.

At best, technology only offers the range of alternatives, a toolbox of tools available to be used. The final decision which tool to use is a decision of purpose and intention. Technology is neither panacea nor villainy but an instrument. Sustainable development cannot occur without technological innovation unless human society is to devolve back to a tribal or foraging state.

Whatever worldview eventually predominates, or whether a synthesis occurs, it is fundamental to successful environmental reconstruction that the public believe that large-scale changes in the global environment are not inevitable. There must be a will to change. For such change to take place, it is essential that peoples of the world believe that change is possible and likely to succeed. This means that the twin enemies of survival are fatalism and pessimism.

Long-lasting change requires social and cultural change. Through collective action, governments and societies may change the presently destructive course of environmental degradation. The human economic and social systems that depend on environmental exploitation cannot merely be swept aside, but must be replaced by an alternative social order. To succeed, and to be worthy of succeeding, this social order must be humane, effective in responding to social needs, equitable in the distribution of goods, and historically stable. This means answers for the perennial problems of poverty, development, and social justice.

Although there is much to justify a pessimistic view of the world's prospects, we have actually come far in the search for a new way of living. Recent decades have brought a much more detailed view of the environment, rising awareness on the part of people in the developing world, more tolerant values in accepting other cultures, and technological developments that provide tools for constructive application.

Although human beings are responsible for our present unsustainable situation, there can be no solution without accommodating human needs. "Sustainable" must include the sustainment of an evolving and opportunity-rich social environment, preferably heterogenous in character with urban nodes as well as Arcadian hinterland and villages, or it is likely in some future generation to be cast off again as restrictive and stultifying.

The solution ultimately lies in seeing human society as an integral part of the planet and accepting that human communities must be accommodated in a stable world order. This implies a set of social actions that provide alternatives to both wasteful resource exploitation by industrialized societies and the often intensive resource overutilization by impoverished and less developed societies that leads to soil depletion and deforestation. Part of the answer may be sharing technological answers when they come available. Part of the answer may be a global educational and communications system in which societies have access to not only news but insight and explanation for the behaviour of other peoples. Part of the answer may be political evolution away from the nation-state and toward interdependent communities aggregated into stable regional confederations or trading blocs but preserving local traditions and placing value on local communities. A large part of the answer may be in encouraging personal opportunities that are not resource-intensive, putting the energies of the economic system and the people into community development, health promotion, education, the arts, and popular culture.

Ultimately, the economic system must shift from a basis of sustaining development and production to a basis of sustainable development and selective production. This cannot be achieved by a command economy of the type that so recently failed in the communist bloc. It requires that markets and prices be connected to resource availability in a very direct and explicit way. It also requires that the true cost of transportation, agriculture, and the distribution of goods be reflected in pricing and that people have sufficient resources, sufficient education, and sufficient choices to respond to these price changes with reduced demand or the selection of alternatives long before the resource base becomes damaged. The emphasis must not be on partisan political changes but on structural change to make society responsive to these issues and to diffuse responsibility for environmental reconstruction to the lowest possible level. The emphasis also must not be on the recreation of a peasant society with uniform social organization and orthodox values, but on a new and diffused form of aware and cosmopolitan culture, rich in human opportunities and displacing the need for material exploitation.

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Tee L. Guidotti, MD, MPH, FRCPC, CCBOM
Professor of Occupational and Environmental Medicine
Occupational Health Program
Department of Public Health Sciences
University of Alberta Faculty of Medicine
em guidotti@PHS.Med.UAlberta.CA

Presentated at the First International Symposium on Ecosystem Health and Medicine, Ottawa, 19-23 June 1994.

Disc #15, Address Urbeco.Pap


Urban systems are among the most critical areas of study in the environmental sciences and among the least appreciated. Cities represent a concentration of human activity for efficiency and interaction. Although they may represent processes that are at the root of ecosystem exploitation and degradation, they also hold the potential for minimizing human impact on the surrounding ecosystem if properly managed and integrated. Cultural concepts of ecosystem and human health have been linked with thoughts about cities and human settlements since ancient times. There has been a progression of these concepts through religious ideas, philosophical systems, sanitation, toxic substances, and, most recently, the risk of ecosystem change on a large scale resulting in the collapse of global and regional system that sustain human communities. However, ecosystems are not really destroyed; when ecosystems are pushed to the point of failure, they convert into something else and the human communities that depend on them adapt. The conversion and adaptation may not be desireable or productive, but they occur. Cities are the best examples of this. Urban systems are artificial ecosystems that preserve but subsume the preexisting natural ecosystems. We need a new way of thinking about ecosystems and human health that does not place human beings at the center and that is not driven by effects of individual exposures or perturbations. We also need to appreciate the value as well as the cost of cities. Urban ecosystems have characteristic pathologies. Those that place great stress on natural ecosystems or that are overly stressed in their own carrying capacity are not sustainable. There is an urgent need for valid indicators of "health" in urban ecosystems: one measure may be how well it adapts and the way that it responds to external stresses. This is a behavioural measure, reflecting the viability of the human community.

It is in the nature of humans as primates to be social and to live in communities. Our communities face problems common to all species: the need for food, shelter, procreation, and protection. Our culture and capacity to communicate and to learn has added a considerable layer of secondary needs, presenting additional problems of demand and satisfaction. Our solutions to these problems are collective and the systems we have set up to provide for these basic needs are institutionalized in cities. How cities function, the sustainability of these systems, and their meaning for human health is, in my own opinion, one of the most critical areas of study in the environmental sciences and one of the least appreciated. (Guidotti 1972) There is a considerable need for indicators and methods to assess the integrity of ecosystems, both natural and artificial, and the urban systems that sustain human communities. First, however, it is necessary to understand these systems, their capacity to function, and the determinants of their performance. Unfortunately, there is not much interest in urban studies in 1995 compared to 1970. Then, t seemed that sensible urban and regional planning could solve so many intractable urban problems. The dynamics of community had been reintroduced by Jane Jacobs (Jacobs 1984, Jacobs 1961, Redfield and Singer 1969), Mumford (1961), and like minds, and others with different philosophies (Soleri 1984, Doxiadis 1974, Soleri 1969, Sennett 1969, Goodman and Goodman 1960) into what had been rather barren thinking about cities. (Breese and Whitman 1953) Sweden played a disproportionate role in the discussions at the time, because that country at that time believed that it had achieved a level of social security that had largely removed the confounding factors of income inequity and discrimination. (Carlestam 1971, Engstrom et al. 1971) Swedish social scientists appeared to believe that they were examining a new phenomenon, a post-industrial urban environment in which the social determinants of human health could be examined directly. At that time, concepts of urban health and environmental quality were even sufficiently influential to affect legislation in the United States, which in general has been very resistant to such ideas. (Pond 1978) The heyday of planning as a comprehensive approach to understanding and rationalizing urban systems seems to have passed, brought along in its demise by a literature that, while poetic, was usually more strident and ideological than empirical and demanding.

How can we start again to understand the city and its profound but often subtle effects on health and its interaction with natural ecosystems? Perhaps the best place to start is at the beginning, thinking through the issues from first principles and picking and chosing selectively from the literature.

Cities play many roles in human civilization. We are indebted to Jane Jacobs for identifying many more than we may have previously suspected. She has described the role of cities as centres for economic activity and social change, and a cultural crucibles in which the concentration of people and activity allows the necessary critical mass for growth and maturation. Cities offer personal opportunity and have been engines for changing attitudes and cultural development. (Jacobs 1984, Jacobs 1961) There is also a case to be made for cities as a strategy for minimizing human impact on the surrounding ecosystem, paradoxically. Although the experiments and ideas of Soleri (1984, 1969), Doxiades (1977, 1974), Garnier (Wiebenson 1969) and others now seem, after twenty or thirty years of contemplation, to be grand follies, the idea that cities can be designed to concentrate human activity into a restricted scope, achieving maximal efficiency with minimal environmental disruption, remains attractive and unrefuted. Mumford (1961) wrote that "...the concentration of an urban population may create a beneficent ecological pattern, providing soil removal and crop improvement - if based on composting, not wasting." He was writing of medieval cities that reduced the impact on their local ecosystem compared to numerous scattered, poor villages. The problem is partly one of scale and partly one of the efficiency and sustainability of urban systems.

While it is clear that we are not presently designing our cities in this way, it is also clear that with our decentralized, accretional, individually liberal patterns of urban growth we have not really tried. The trick is to achieve a plan without subordinating the values that make urban living attractive. Is it possible, for example, to have a Singapore with personal freedom of expression, or a Hong Kong with opportunities for cultural diversity, and to make both nodes in an efficient system that minimizes the disruptive effect of the inevitable trading systems needed to sustain them?

Ecosystem and Human Health: Historical Concepts

Concepts of the relationship between ecosystem and human health have had a long and involved historical evolution. Hippocrates spoke of "airs, waters, and places," and the importance of correct siting of human settlements, quoting ideas that were probably half religious and half practical. (Mumford 1961) The Chinese system of "feng shui", likewise, guided siting and planning decisions for centuries. Vayda (1969) provides numerous examples of cultural mechanisms by which tribal and traditional societies manage the ecosystem by ritual, kinship relationships and resource allocation, and economic systems, all governed by religion, mythology, or other systems of belief. Mumford (1961) reviewed the entire history of cities, observing that the earliest cities were often patterned after religious ideas and served religious purposes, which happened to be practically useful as well by concentrating human activity. He concluded that the city was patterned after a cultural model of human relationships with other humans and with the material world, not necessarily understood as an ecosystem, that supports human life through production. As these largely hidden, implicit models of urban development progressed, the religious themes were replaced by secular philosophies and pragmatism.

Early cities were probably safer than the surrounding hinterland because of increasing prosperity and better protection. As cities grew, developed increasing problems with waste disposal, fostered an underclass, strained the fresh food distribution system, and became foci of epidemics, the healthiness of urban residents probably declined relative to the peasantry. Following the Industrial Revolution, a public health crisis became apparent in urban life and cities became perceived as pestilential.

Prior to the modern germ theory of disease, the doctrine of "miasmas" guided concepts of human health and its relationship to the environment. Then, a series of revolutionary developments occurred that placed these largely intuitive ideas onto an objective, scientific basis. In the mid-nineteenth century, the so-called Sanitary Revolution in Europe introduced a quasi-scientific basis for relating human health to environmental quality and the later demonstration of the existence of pathological microorganisms identified the responsible agents for the type of "contamination", exposure to which resulted in the most common types of epidemic human disease. (Briggs 1968, Weber 1899) At last, a specific and tangible link could be found between the placement and cleanliness of human settlements and human disease. Writers of the day describe the cleanliness of the human environment as the "first and most important point among all considerations" in preventing diseases such as cholera. (Buchner 1876) The germ theory of disease provided a paradigm that appeared to describe the relationship between human health and the environment quite satisfactorily until Rachel Carson drew attention to the role of toxic substances by sounding an alarm over the indiscriminate use of pesticides. (Carson 1962) Toxicology ceased to be a discipline describing the exceptional exposure in unusual circumstances and came to be viewed as the science that describes the normal set of affairs when an organism is bombarded by a continual onslaught of chemical exposures, to which it must adapt or succumb. The issue insofar as urban systems are concerned was then to optimize planning and controls over urban development in such a way as to minimize pollution. (Kaplan 1978; Werczberger 1975) Working through the rather morbid, fearful world view that has resulted from this emphasis on toxic substances has consumed much of the past three decades. There are many reasons to believe that in our haste to sound the alarm over the thoughtless dissemination of toxic substances in the environment, we have created a type of paranoia generalizing to all chemicals, represented at its extreme by the false medical construct of "multiple chemical sensitivity" and by an obsessive chemophobia in society that does not distinguish between ecologically trivial exposures, such as the application of 2,4-D on lawns, and the massively destablizing effects of seeming benign and even necessary economic activity, such as foreign trade. In each case, the world view is firmly centred on humankind and the effects of specific exposures on susceptible people in the larger population.

Recently, our attention has been forcefully drawn to examples of ecosystem change on a large scale and the prospect of collapse of those environmental systems that sustain human communities. (Guidotti 1993, Guidotti and Last 1991) Admittedly, the history of forecasting ecosystem collapse has been almost uniformly a failure. Despite numerous such projections, as, for example, the dire predictions of the Paddock brothers (1967) in the book Famine 1975!, ecosystems do not collapse overnight in ways that we have convinced ourselves to predict. They show much greater robustness that we have previously given them credit for. Indeed, we are coming to realize, largely from contemplation of the implications of global climate change (Guidotti 1993, Guidotti and Last 1991), that when ecosystems are pushed to the point of failure, they convert into something else and the human communities that depend on them convert as well. The huge, dense forests of western Europe are almost forgotten except in Wagnerian operas. The natural terrain of Toronto is carved into a patchwork of municipalities linked by great trading networks to distant sources of goods and services that sustain its completely artificial economy. Newfoundland has been devastated by the clearest example of an ecosystem collapse yet to be found in Canada, when the cod fishery failed apparently through a combination of overfishing and altered ocean environment. An entire province of a major industrial nation is now converted into a dependent state propped up by a larger economy and made manageable by emigration. However, the ecosystems did not disappear. What results is not necessarily desireable or even agreeable, but adaptation does occur and in real time.

Now we are engaged in shaping a new paradigm that is in some ways a return to the older ideas of airs, waters, and places. Can we conceptualize a relationship between human health and the integrity of the ecosystem that does not place individual human beings at the centre and effects that are not necessarily mediated by specific exposures? Is there a relationship between human society and the ecosystem that is not mediated by either adverse exposure (called here "pollution" for convenience) or ecosystem collapse?

The city gives us perhaps the clearest look at how natural and artificial systems are interlinked. The health of urban ecosystems, by definition a mix of natural and artificial systems, gives us a model by which to assess the sustainability of the natural ecosystems that support human settlement.

Urban Systems

Urban systems are artificial ecosystems. Figure 1 provides a schema for examining the relationship between urban activities and resulting environmental problems. Its complexity suggests an analogy with the physiology of the body of a giant organism - not Gaia, but perhaps Urba! The key to understanding the schema, however, is to appreciate that urban systems are initially built on the natural ecosystem and rapidly turn it into a subordinate component of an artificial, hybrid system.

The case of Edmonton, Alberta, is instructive because it is a relatively young city that developed on the fringes of Canadian settlement and was rather isolated for many years. The initial community, which came to be centred in a fort, was based on the availability of fur-bearing species because of the rich forest and river ecosystem and the intensely cold climate. As the economy became more complex, the community obtained its technologically advanced manufactured goods by trade and increasingly exploited the natural ecosystem to provide goods for trade, finally ending its dependence on the natural ecosystem altogether by building an artificial economy based on agriculture and energy resources (which played no role in the natural ecosystems). Finally, the modern city is technologically advanced but remains dependent on natural resources economically and is visually attractive primarily because of the remnants of the natural ecosystem that have been preserved within its boundaries. However, no city of 700,000 could survive on the local carrying capacity alone, nor could the local ecosystem be restored as it was in the eighteenth century. (MacGregor 1975) A similar local history has been documented for northern British Columbia and demonstrates numerous parallels. However, as seen through the point of view of native peoples, this history is catastrophic and represents a systematic degradation of the land and its peoples. (Brody, 1988) From some non-native perspectives, this history can be seen as a successful effort to make the ecosystem more productive by using artificial, technological means. From the native and conventional ecological perspective, however, this apparent productivity is an illusion, created by destruction of an already productive ecosystem and the assembly of a community greatly in excess of the carrying capacity.

Although cities consume the natural ecosystem, it is not accurate to say that they destroy it. Rather, it is more accurate to state that they subordinate it, that they create hybrids that incorporate the natural ecosystem into an artificial system, preserving waterways, for example, but changing their purpose to supply water or carry away waste. Obviously, some remnants of the natural ecosystem remain in parks, rights of way, and protected areas, but elements of the old persevere in unexpected ways. Transportation policy, in particular, has a major influence on urban development and local environmental quality, but it can also be profoundly conservative in maintaining old patterns. The unusual and apparently illogical course of Broadway, in New York, has been preserved since the time of settlement from an ancient native footpath and animal migration route. Likewise, the Don Mills Parkway in metro Toronto has preserved a feature of land contour that is no longer obvious since the waterway has been contained.

The Value of Cities

The first step in understanding the city is to consider the need for urban settlements and to appreciate their inevitability. Cities are logical extensions of the primate need to form social groups, an aggregation of people, skills, societies, and relationships that allow efficient transaction of business and that permit unpredictable interactions. They allow a vastly greater number of relationships and potential interactions than low-density settlement patterns. This is why they are nearly universal in all cultures, and why their substitutes (fairs, temporary marketplaces, and inter-village festivals) are found in cultures that do not have permanent cities. Some are too low in population density or resource availability to support permanent settlements. Others are based on hunting and herding, but all have some mechanism to facilitate interaction through density. In a sense, these substitutes are cities that exist in time, not in a place.

Obvious Pathology in Urban Systems

In the 1970's, there was considerable interest in the health implications of urban planning and a concerted effort to identify a comprehensive list of factors that constituted an "hygienic" environment. Table 1 lists some of these factors, taken from the literature of the day. (Kasl 1972, Carlestam 1971, Senn 1970) The majority are either physical factors associated with the structure of the urban environment and its economic activity or social factors resulting from the pattern of settlement. Throughout these studies, there is a sense of the elusive, that the authors are searching for a pattern or a pervasive influence that is ineffable, that cannot be described in strictly physical or social terms. One of the indirect contributions of Jane Jacobs (1961) to the literature on urban planning was to reintroduce the concept of community, the fundamental issue of how we as individuals view ourselves as integrated into the urban society of which we are nominally a part. (Goodman and Goodman 1960) The path not taken in this debate, it seems to be clear in retrospect, was to investigate how the cues and semiotic messages of urban life (Alexander et al., 1977) enhanced the individual resident's feeling of being part of what was going on and therefore reinforced the link to community so essential to our primate instincts, or how these same cues and messages invoked fear and threats to community. For a social animal, isolation from the pack means vulnerability and death. Integration into the pack means safety and opportunity. Could it be that human beings, as primates accustomed to living in tribes, respond physiologically to the information content of these cues and messages and not particularly to their physical structure? Perhaps the key to understanding the link between the urban environment and human health is not in examining the physical characteristics of the city after all but in the perceptions of its residents and the messages that are constantly conveyed to and traded among urban residents.

Crowding is usually considered to be one of the worst features of urban life. A series of studies performed by Calhoun at the U.S. National Institute of Mental Health and others in the 1960's are frequently cited as evidence for the profound distress that occurs when individuals, either rats or humans, are crowded together into dense communities. (Deatherage 1972; Latane et al. 1970, Morrison and Thatcher 1969, Calhoun 1962, Calhoun 1952) These studies showed an apparent deterioration of social structure among rats in a densely crowded environment, resulting in behaviour that included aggression, passivity resembling human anomie, homosexuality, promiscuous coupling by females, and all sorts of other so-called "deviant" behaviours. Comparisons with the inner city were inevitable.

In retrospect, it is clear that this literature was laden with assumptions about what inner city life was like and ignored common social arrangements that did not present analogies, among them evidence of aggressin and deviant behaviour in the middle class and tribal violence in low density environments. Although it is clear that increased density increases the number of potential interactions for any individual, it is far from clear that the frequency of these interactions alone are responsible for intolerable stress that leads to "deviant" behaviour, much of which may be only normal behaviour released from social inhibitions. It is also far from clear that a rural life and the pressures of small-town living are preferable to most people or that they provide more personal opportunity for expression.

Unlike experimental rat populations, human communities are highly structured with mechanisms for individuals regulate or adapt to the frequency of their encounters with others. Increased density is sought by many as an opportunity for stimulation and interaction and tends, all other things being equal, to increase the number of possible opportunities for trade or personal gain for every individual, although not everyone may be in a position to benefit. Thus, for every slum area in New York, there is a Hong Kong and for every Lagos there is a Shanghai, where people expect that their lives will be better and act accordingly. In reaction to simplistic studies of crowding, there has developed a considerable literature that runs counter to the original conclusions of Calhoun and others and that suggests that it is meaningless to isolate crowding from other social factors. (Altman 1975, Baldassare 1979, Freedman 1975, Guest 1979) More persuasive is the observation that bad urban design can be a potent stressor, both on the individual and on the community. (Engstrom et al. 1971) In a poorly functioning urban environment, a considerable amount of energy is required to get through the day, to accomplish one's tasks, to sort through the bombardment of messages and the visual and aural stimuli, and to achieve and maintain personal and family security when the economic system is unreliable or unfair. This may or may not result in obvious clinical disease, but may well express itself in socially-mediated pathology such as family stress or individual pathology such as sociopathic behaviour. For some susceptible individuals, there may well be stress-related clinical disease, such as mental illness, psychosomatic disorders, and substance abuse. Urban systems that are not sustainable, for whatever reason, will create such stresses and will fail to relieve such stresses because of their inadequacy in providing the support systems of a community.

What Constitutes a Healthy Urban Ecosystem?

Urban ecosystems that either place great stress on natural ecosystems or that are overly stressed in their own carrying capacity are not sustainable. Although they may not be in imminent danger of collapse, at least in the style communicated by science fiction and fantasy, they are at risk of conversion into a form that is at least undesirable. At worst, the health and vitality of individual residents of the city and region may be affected and the impact may be disruptive and negative on vast and distant regions required to support the dysfunctional city. One could argue, for example, that a city that has exceeded its sustainable size, such as Toronto, must continue to grow or risk the urban equivalent of death: conversion into a lifeless settlement where survival takes precedence over cultural growth and the economic support systems are inadequate to support more than a rudimentary quality of life. So-called "urban sprawl" has many dimensions and both positive and negative effects. (Popenoe, 1978) In general, the positive effects accrue to the benefit of the individual resident and the negative effects are distributed on the region and city core; this was recognized in the 1970's. Not appreciated in the 1970's, however, was the end-game, in which the centrifugal tendency of a region's growth might reach a critical point at which the urban core would again seem attractive to investment and settlement.

If the city outstrips its sustainable growth, what occurs is not a total collapse, but a decline to a particular level that may be higher or lower depending on the local economic underpinnings. Mechanisms built into the pricing structure of the local economy swing into action to stablize the urban core and even to bring it back; the tragedy is that they do not work quickly so that their effect saves one generation, although it may save the next. The inadequacy of life in a decaying city accelerates flight to outlying areas, until the centre has declined to the point where psychological perception forces an economic undervaluation at the centre and it becomes "good business" to rehabilitate. However, rehabilitation is a spotty and incomplete process. It does not raise all boats together and can create substantial tension by raising the value of adjacent property, with implications for older residents in intolerable property taxes and younger residents in making housing inaccessible. To the residents of marginal neighborhoods, it looks as if rehabilitation is distorting their property values; one could make the case that the real distortion occurred with the under-valuing of property during the period of decay, however.
"Unhealthy" urban ecosystems undermine their own viability. They have intrinsic patterns of exploitation or land use or social interaction that tend to exaggerate the process of urban decline and that destablize the urban systems on which human communities depend. In particular, they create increasingly disconnected artificial systems with little regard for sustainability.

The direct and indirect consequences of this lack of sustainability may place the health of residents at risk. Environmental health issues in an urban context are both risks to the health of the urban population and symptoms of an "unhealthy ecosystem". For example, water quality control systems may break down. This is a surprisingly common event, even in modern cities. However, the most profound effects of unhealthy urban ecosystems are probably those mediated by indirect, largely social mechanisms. For example, the complicated conundrum of inner city poverty, substance abuse, family disintegration, and sociopathic behaviour from which we cannot seem to escape, even when our cities were more affluent and our social services more nearly adequate to meat the need. These are general mechanisms that condition a dysfunctional response to any stress, be it the collapse of the cod fishery in the Grand Banks and the subsequent repercussions on the street in St. John's, Newfoundland, a recession in southern Ontario, or the failed integration of natives with the urban life of Edmonton. There is an urgent need for empirical research to identify valid indicators for "health" in urban ecosystems. These indicators should be robust, polyvalent (meaning that they reflect in one measure many axes of well-being in a community and accurately reflect interactions among urban factors), accessible, and easily understood by decision-makers. Simple economic indicators such as unemployment, physical measures such as air quality monitoring, and direct health measures such as reportable diseases do not suffice. They measure part of the problem, not the problem itself. What is truly needed is a system that synthesizes several measures to summarize the dynamic interaction of urban systems and the commitment to behavioural change that is inherent in the city's culture and the attitudes of its citizens.

Perhaps the most salient measure of the health of an urban ecosystem, and urban society in general, is not a static message of current status. Perhaps it should be a dynamic measure of how forcefully, effectively, and consistently the urban complex responds to issues and destablizing developments. That is a true test of its sustainability in the face of changing and on-going challenges.

This concept is incorporated in a recent definition of "healthy community" proposed in the context of the health promotion and the safe communities movements:

a healthy community is a community in which all organizations from informal groups to governments are working effectively together to improve the quality of all people's lives. (Boothroyd and Eberle, 1990)

Likewise, we have argued elsewhere that air quality in metropolitan areas is more than an inventory of pollutant concentrations over time. Air quality is also a cultural and social phenomenon reflecting individual and collective behaviour. (Guidotti, 1994) This leads to a different approach to assessing the health of urban ecosystems. Instead of perceiving this assessment as a measurement of status at a given period, perhaps it is more useful to conceptualize the health of urban ecosystems as a process and the various measures of media quality, land use, ecosystem integrity, and population health as outcomes reflecting community behaviour. In this new context, the indicators of community health and ecosystem integrity are outward manifestations of a deeper behavioural problem - a collective psychological pathology of the human community.


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Physical Factors

Physical safety, risk of injury
Water quality
Air quality
Infections agents, communicable disease risk
Chronic disease risk, real and perceived
Visual overstimulation, confusion, ugliness
Housing quality

Social Factors

"Disharmonious behaviour"
Substance abuse
Financial concerns, poverty
Limited personal opportunity
Forced pace of work
Excessive competition
Risk of crime against person
High frequency of acts criminalized by social convention (prostitution)
Lack of access to recreation, quiet, stress-reducing activities

Additional Factors (Not Emphasized in the Older Literature)

Domestic violence, verbal and sexual abuse
Underemployment, job instability
Cuing behaviour (waiting in line) and rationing
Political apathy and cynicism
Inequity in income and opportunity


Circles represent structural components of the city or region. Rectangles are environmental problems to which activities of the urban region contribute. The central "Urban Systems Complex" represents the economic processes of production, conversion, distribution, and transportation, and the control functions of political process. The Resource Pool is the source of nonrenewable resources. Agriculture is the source of food, fibre, and other renewable resources.

Solid lines are economic operations. Broken-solid lines are processes that cause or contribute to ecosystem problems. Broken lines are inhibiting influences on social structures. Dotted lines are interactions between ecosystem effects.

Economic Functions

1. Extraction of nonrenewable resources (mining)
2. Recycling of previously converted resources
3. Extraction of renewable resources
4. Food distribution
5. Labour force

Processes Generating Environmental Problems

1. Waste in economic operations
2. Consumer and domestic waste
3. Manufacturing, conversion, and municipal services
4. Domestic and vehicular emissions
5. Fugitive emissions and effluent, from manufacturing and conversion
6. Sewage and municipal waste
7. Agricultural waste and effluent
8. Economic and cultural attraction, development
9. Internal ("natural") population growth, immigration

Inhibiting Influences on Social Components

1. Blight, disposal costs, pest breeding, hazard
2. Risks to health, materials, species, aesthetic values
3. Costs of clean-up,. remediation, decontamination for use; loss of utility
4. Crowding, visual blight, social fragmentation, noise
5. Dumping, land pollution, hazardous and nonhazardous waste
6. Crop and stock damage
7. Salinization, contamination of soils
8. Urban encroachment on argicultural land, poor land use planning

Interactions Among Problems

1,2. Alternative disposal methods, interconversions
3. Concentration, density, and urbanization

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Assessing the Health of Urban Ecosystems

Tee L. Guidotti
Dept. of Public Health Sciences
University of Alberta
What is "Ecosystem Health"

• Definition in transition
• Biological productivity
• Capacity to perform biologically important functions
• Biodiversity and stability
• Evolutionary "momentum"
• The "restoration" debate

What is Health in Context?

Human beings
• "Whole", complete
• Free of disease
• Reduced risk
• Capable of carrying out normal functions
• Productive, integrated
• Empowered

• Integrated
• Free of degradation
• Adaptable to change
• Intact functions (e.g. trophic levels)
• Productive, biodiverse
• Evolutionary

Urban Systems as Ecosystems

• Replace or subsume natural systems
• Anthropocentric
• Require constant energy, resource inputs
• Cities may minimize human impact on environment
• Social controls to allocate resources
• What is health in this context?

Urban Ecosystems

• Artificial, human creations
• Subsume natural ecosystems
• The "ecological footprint" (Leiss)
• Emphasis on human environment
• Cultural dimension
• Human security and needs
• Sustainability of urban ecosystem

Healthy Urban Ecosystems

• Capacity to meet human needs
• Sustainability
• Adaptability
• Opportunity
• Security
• Self-correcting mechanisms

Indicators of Urban Ecosystem Integrity

• Economic indicators
• Social trends
• Environmental quality monitoring
• Land use patterns
• Personal/family satisfaction
• Adaptability

Environmental Indicators

• Environmental quality
• Resource utilization
• Env health outcomes
• Population patterns
• Env issues
– political
– economic
– physical
• EQ trends
• Ecological footprint
• EH monitoring
• Sustainability
• Response to env issues
– sociopolitical
– economic
– physical

Response as an Indicator

• Adaptability - Does the city manage without making the problem worse?
• Resilience - Does the city cope?
• Environmental response - Are ecological mechanisms adjusting (e.g. succession)?
• Politicosocial - Are residents reacting?
• Economic - Is there investment in solutions?

Example: Air Pollution

• Are AQ issues recognized and monitored?
• Is the city attempting to mitigate effects?
• Is the city coping with the problem while retaining desire to solve it?
• Is there green space to protect airshed?
• Are their moves to reduce/control emissions?
• Are costs accepted as an investment?

[A] healthy community is a community in which all organizations from informal groups to governments are working effectively together to improve the quality of all people’s lives.

Boothroyd & Eberle (1990)
Healthy Cities

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