George Bugliarello

Today's worldwide rapid rate of urbanization and the development of very large urban concentrations are a new phenomenon that impacts in unprecedented ways human society and the Earth. Many facets of the phenomenon still elude us, and so do the actions needed to make an urbanized world more livable and sustainable.

THE PHENOMENON

Cities emerged some ten thousand years ago as the result of the invention of agriculture, which freed human populations from the nomadic existence of huntergatherers. Major urban concentration arose already some five thousand years ago in the fertile crescent of the Middle East, in Egypt, and later in China. Later yet, Athens and Rome became the epitome of urbanization in the period of classical antiquity in Europe; large urban concentrations also occurred in Mexico, Central America and Peru. Rome, with a larger population than Athens, and with sophisticated public works, became a prototype of integrated urbanization-of the integration of production, trade and habitation that are the most fundamental functions of a city. That integration became a guiding concept for cities throughout the Roman world, but vanished in the medieval decline that followed dissolution of that world, to emerge again, imperfectly, in the cities of the late medieval period. It continues to be a universal aspiration for today's cities (Saalman).

The technological explosion ushered in by the Industrial Revolution, and the improvement of public health in the last century spurred a growth of cities that continues unabated today. Thus since the earliest beginnings, technology-at first agricultural technology, but also construction technology and civil engineering-has been the determining factor in the genesis and evolution of the cities. Among the many technological revolutions that have influenced that evolution, at the turn of the nineteenth century water supply and purification works made possible the widespread development of healthy large urban concentrations and the elevator, together with steel and concrete, made possible the vertical city; in the twentieth century, the automobile created the extended suburb and urban sprawl, and later in the century, aviation gave direct international access to landlocked cities in the interior of continents. Today telecommunications are affecting cities in still unfathomable ways.

Statistics about the concentration of populations in cities have led to a widespread characterization of the urbanization phenomenon as an explosion. A few statistics will suffice. The percentage of world population living in cities greater than one hundred thousand rose from five in 1900 to forty-five in 1995 (2.5 billion people). It is projected by the U.N. to reach sixty-one percent in 2025 (United Nations, 1996, 1998). In China, for example, the number of cities increased from 193 in 1978 to 663 in 1999, and the urban population from 172 million to 388 million (Yongxiang). In the developed world, cities of one million increased from forty-nine in 1950 to 112 in 1995, and in the developing world, from twenty-four to 213. In 1975, cities with population greater than ten million, currently defined by the United Nations as megacities, were only two in the developed world and three in the developing world; in 2015, that number is expected to double in the developed world to four, but to increase to twenty-two in the developing world. Thus very large urban concentrations are primarily a phenomenon of the developing world. This is underscored by the changes in the eleven largest urban agglomerates. In 1980 New York City (the New York City metropolitan area) with a population of 15.6 million, ranked second among the eleven largest urban agglomerates in the world. It remained so in 1994, but by 2015 it is projected to fall to eleventh place. At the same time, Mumbai and Jakarta, which did not rank among the eleven largest urban agglomerations in 1980, rose respectively to the sixth and the eleventh place in 1994, and are expected to further rise to the second and the fifth place in 2015. In the year 2000, about 4.3 percent of world population lived in megacities. By the year 2015, that figure is expected to exceed five percent (Brennan-Galvin; Population Institute; United Nations, 1996; United Nations, 1998; World Bank).

Pragmatically, large urban concentrations are unique instruments of creativity, ideas, and psychic energy; instruments ofwealth creation and globalization because of the connection that they establish with each other; instruments of enhanced social development because of the institutions that are housed in them; and also powerful instruments of birth rate reduction. Cities, and particularly the large urban concentrations, attract because of expectations of a higher quality of life-jobs, less hardship than in the countryside, education, better health care, and a higher level of social interactions. The ability of a city to support many elements that contribute to the quality of life, such as theaters, sports arenas and universities, is generally correlated with its size. A city of thirty to fifty thousand inhabitants often cannot support a stable orchestra, which typically may require aggregations of some 250,000 in population; a large sports arena requires larger populations and a large international airport even larger ones.

At the same time, large urban concentrations are in most cases dysfunctional. They are concentrated sources of pollution; they are harbors of poverty; they are congested (for instance, China has ten times the number of persons per room as the United States); they have, particularly in the developing world, large infrastructure deficits in water supply, in sanitation, in transportation and in telecommunications (World Bank). They are difficult to manage and they are also risky. In their expansion large urban concentrations are increasingly exposed to natural hazards, from earthquakes to floods, and to the spread of communicable disease among a very concentrated human population, as well as to the interruption or destruction of the many systems on which their life depends. In a more subtle way, life in highly artificial environments also may make it easier for the inhabitants of the city to lose awareness of global ecological issues.

By and large, the increase in large population concentrations occurs not only because a city attracts, but also because in its growth a city engulfs populated areas that surround them. However, population statistics about urbanization must be taken with a degree of caution because of lack of uniformity as to how they are gathered and reported, starting with the question of how a city is defined. For instance, if New York City is defined as a municipality in the state of New York, its population would be about 7.5 million people. If it is defined as Greater New York, spanning also its northern suburbs, New Jersey and the southern part of Connecticut, its population would be much larger. Also problematic are projections into the future, starting with those of the U.N., based, as most demographic projections are, on interpolation of past trends rather than on models that take into account the major economic and social factors that will affect the dynamics of the population (Brennan-Galvin, 2000). Furthermore, there are still very few metrics about large urban concentrations that would make it possible to gain a better understanding of the interrelations among these factors and to measure and benchmark the performance of urban concentrations across the globe. Typically, each city has its own way of making projections, and each department within the city has its own data base, seldom integrated with other data bases. Thus projections can be way off the mark for a city and for the ensemble of all cities.

A description of the phenomenon represented by these large urban concentrations requires, however, far more than just population statistics. Data are needed on social and environmental costs and benefits of the economic activities in the city, because increasingly, urban regions are the principal basis of the global economy. There is, for instance, even in the most advanced cities, little systematic information about the economic impact that projects in a city have on households, particularly by income level, on national and local government, on individual industries and on the urban region as a whole. Neither are there clear data for the gross urban product, that is, the gross economic product of an urban region, and for money flows between production, consumption, savings and investment, data about the share of income that goes to workers, to taxes and profits, about the urban area's balance of payment, or data about the consumption and production of energy (Shore). (In general, it appears that higher population densities lead to lower per capita energy consumption.)

Environmental accounts are needed to establish a monetary value of the . degradation and enhancement of environmental assets in order to calculate, for instance, the increased value of clean-up activities versus their cost or to add to the cost of urban travel the cost of the. environmental damages that travel creates.

Another set of needed data has to do with the quality of life. The assessment of the quality of life is somewhat arbitrary, although a number of attempts have been made to identify criteria, such as availability of recreational and transport facilities, crime statistics, education, jobs, etc., that, taken together, give a possible indication of the quality of life. The cost of waiting, an ubiquitous phenomenon in our large population concentrations, should also be taken into account. It can be said that, in most cases, cities of the developing world have poorer quality of life than the developed world cities. However, regardless of whether they are developing or developed, some cities are characterized by higher quality in certain parameters, for instance sports and leisure, and other cities in other parameters, such as efficiency of transportation and quality of health care.

Collection and integration of the information about the geographical size of the cities, mortality, water and land use, health, education, income distribution, etc., are today only episodical, but urgently needed in order to understand urban complexity and the global impact of these human habitats. For instance, we need to better understand the causes and possible remedies for the persistent urban poverty and disease that characterize the explosive urban growth in developing countries and lead to dangerous imbalances with the developed world. That world, however, is not immune either to the influences of poverty and disease within its own cities. In the American cities, twenty-five percent of AIDS occurs in African Americans, who represent only fourteen percent of the population.

From the purely geographical viewpoint, physical features ofthe landscape or the dangers presented by natural hazards such as floods, earthquakes, or volcanoes, are increasingly less of a deterrent to urban expansion. Throughout the world, that expansion continues undeterred by obstacles or potential dangers, engulfing also every greater portions of coastlines. The changes to the earth's surface caused by the presence of a city are dramatic. For instance, over eighty percent of the surface of Tokyo is occupied by buildings, concrete and asphalt and has thus become excluded from the normal hydrological cycle. In the typical American city with a high proportion of individual dwellings that percentage is less, but not much less in Manhattan. Much of the groundwater removed from under a dense city footprint cannot be replenished when precipitation cannot penetrate the surface because of the large extension of paving. In several cities this can lead to inordinate manifestations of subsistence, as in the case of Mexico City (World Resources Institute).

The footprint of a large urban concentration has multiple dimensions. It encompasses not only the area physically occupied by the city, but also the area that contributes resources to the city and the area that, in turn, is affected by the outflows from the city, from waste to air and water pollution. This extended footprint is that much greater, the greater the population of the city and its affluence. (Hence the enormous impact of megacities and other large urban concentrations.) Although some studies have been performed to determine the size ofthat footprint, information is still very scanty. It has been reported, for instance, that a Baltic city of one square kilometer uses the resources of eighteen square kilometers of forest, fifty square kilometers of arable land, and thirty-three square kilometers of marine surface (Rowland). An affluent city may use daily some 0.6 tons of water per inhabitant, most of it transformed into waste water, and may absorb daily some five pounds of food per inhabitant, virtually all of it becoming waste (most of it dispersed not too far, within two to three hundred miles). Again, reliable information as to this balance is very limited and episodical. It has been roughly estimated that in a modern city in a developed country, if all the materials that flow into it, from stone to wood to metals to plastics to carbon-based fuels, were to be spread evenly over its surface, the ground would increase in height by five centimeters per year (Graedel). About three centimeters of that height are removed as waste every year, so that the net material growth of the city would be two centimeters per year, or twenty meters in a millennium. Thus the city is a great accumulator of materials embedded, e.g., in the cement of houses and bridges, the asphalt of roads, and the metals of machines. Rather than eventually being left as detritus or waste, those materials could be mined ("city mining") and remanufactured to provide part of the resources consumed by the city, thereby reducing the city's resource footprint.

The urban atmosphere contains two main pollutants, ozone and particulate matter. Ozone is formed by photochemical processes and arises from the interaction of CO and NOx; typically the concentration of NOx is now more than double its background values. In general, the higher the temperature, for instance in the carburetor of an automobile, the higher the NOx production. Hence, in large urban areas with intense automobile traffic that production is very high and very concentrated. CO is due to the carbon content of the typical fuel. In cities without strong measures to reduce traffic pollution it can reach twenty to thirty times its background concentration. In general, pollution plumes from the affluent and energy intensive northern hemisphere travel a very long distance. They reach from the Asian continent to the American continent (Wilkening et al.); new pollution plumes generated there can reach to Europe, where again the pollution generated there reaches back to Asia. In effect everyone is downwind of someone else. Within a city, topography has a significant effect on pollution levels. Thus the average permanence of air over New York City is one half day, but in Mexico City air stays over the city much longer, one and a half days, because of the configuration of the valley in which the city is located (Rowland).

THE CHALLENGES

Beyond the environmental challenges, a number of social and sociotechnological challenges affect the fitness of a large city as a human habitat and hence its future dynamics and configuration. Major among those challenges are jobs and education, health, infrastructure, and management. In the developing world, the challenge of jobs is extremely serious. There are large segments of the population of large cities working in an informal sector, devoid of health care assistance and other benefits, being made rapidly redundant, as in the case of artisans, by new technologies and large enterprises, and having limited mobility and hence access to jobs in other parts of a city because of lack of transportation. This perpetuates poverty and the existence of slums and of barrios and favelas, typically at the margins of the city. As to health challenges, two major causes of concern, beyond air and water pollution, and the disposal of waste, are disease and violence. The exposure to unfamiliar pathogens can lead to a high rate of infection, exacerbated when poor nutrition weakens resistance, as well as by the fact that many cities, particularly in the developing world, have a low level of immunization and an inadequate public health infrastructure. The danger of contagion is high and can spread worldwide. Violence is an extreme challenge to human survival in cities. The most extreme case of violence, barring wars, is a terrorist attack, for which large urban concentrations can be a prime target. Also, the ubiquitous frustration of the daily life in a congested city and the opportunities that may be denied to segments of the population can lead to violence.

Infrastructure challenges are universal, but, again, particularly acute in the rapidly growing cities of the developing world, not only because of major capital shortages, but also because of deficits in knowledge, both in its generation through research, and in its dissemination and utilization.

The management challenges of a large urban concentration are extremely complex and crucial. The first challenge is growth versus stability, that is, how to fmd a viable balance between social equity and economy efficiency-between jobs and good living standards for all citizens on the one hand and the ability of the city on the other hand to compete in worldwide markets with other cities. This requires at times some preferential treatment that conflicts with an equitable distribution of resources to all the citizens (what can be called "the Mayor's dilemma" (Bugliarello, 1999)). In the long run, only by placing itself in a position to successfully trade and compete can a city acquire the resources it wishes to have for its inhabitants.

Subsidies are a second major management challenge. One of the problems of many cities, particularly in the developing world, is that subsidies preclude new investments in urban services. For instance, when subsidized water is distributed to everybody, even to those who are willing to pay for it, rather than just to those who cannot, revenues are insufficient for maintenance and for bringing the water supply system up to date, thus creating a spiral of increasing inadequacies and decay.

A third management challenge is how to avoid the vicious circle that starts with the attraction a large urban concentration may hold for people from the outside. That attraction leads to growth that brings with it high real estate costs, slums, health care problems, shortages of water and energy and environmental problems. These counterproductive consequences end up by reducing the attractiveness ofthe urban concentration to those people who came to it to seek opportunities, a better environment and a better life. For example, Bangalore, in India, became a good base for growth because of climate, skilled population, and transportation, attracting business and jobs, but now begins to suffer from many of these negatives (Math). A related dilemma associated with large urban concentrations--a national dilemma--is their relation to the rest of the country. In virtue of the magnitude of their population and the concentration of economic activities, large urban concentrations exert an overwhelming influence on the rest of the country. For instance, Karachi, in Pakistan, represents twenty percent of Pakistan's gross domestic product and generates fifty percent of the government revenues.

The last, and ultimately the most basic challenge in the management of large urban concentrations-indeed of all cities-is how to involve the citizens in the decisions that affect their lives and determine the nature and configuration of a city. When that involvement and active participation are deficient, cities suffer and plans are unrealistic, as in the design of Brasilia.

Increasingly available to the management of a large city are a number of powerful new tools that can help to address these issues. They range from geographical information systems, to simulators, enhanced communications systems, city-wide area networks, and data banks. With these tools, management can, for the first time in history, obtain more precise data about the city, project those data into the future, develop effective mechanisms for community participation, improve the possibility of developing synergies with other large urban centers that face the same problems and, by joining forces with those centers, fmd the resources and create a market for needed urban innovations. The tools also include new technologies, such as environmental bio-technologies and technologies for rapid excavation and construction, that reduce the upheaval in the streets and make it possible to build rapidly new elements of the infrastructure.

BUT WHAT IS A CITY?

Views of what a city is are more than purely philosophical speculations with no practical impact. They can influence powerfully the development of large urban concentrations. Le Corbusier saw the city as the grip of man over nature (Le Corbusier). Others may see the city as part of a continuum of natural systems that start at the cellular level and lead all the way to the city and the biosphere. The President of Chinese Academy of Science says that, "unlike biological communities... [the city is] a kind of artificial ecosystem dominated by technology, sustained by natural life support systems and motivated by social behavior. It is a socio-economic natural complex ecosystem" (Yongxiang). The present author views the city as a bio-socio-machine ("biosoma") entity in which the advantages, balances and trade-offs among as well as within its three inextricably interwoven components affect the design and function of the city. The biological component, constituted by the inhabitants, is the realm of emotion, feelings, self-replication (Bugliarello, 1998, 2000). Other living organisms within the city are at the base of many natural processes and of recycling. The machine component--that is, all the artifacts in the city, from bridges, roads, buildings, to machines, automobiles and power lines--provide reliability, precision and power. The social component--the society in which the lives of humans are embedded in the city--has characteristics between those of the biological and the machines realms; it exhibits precision in its bureaucracies, emotions in its collective moods and self-replication in the continuity and regenerative power of its organizations. Biosoma balances are exemplified by those in the biological domain between humans and other species--plants and animals--with impact on bioremediation and city vegetation, by those between the individual and society (e.g., issues of employment, privacy, health care), by those among disparate social organizations and activities, by those among a multitude of machines and technologies (e.g., the automobile and the streetcar), and by those between biological organisms and machines (e.g., between vegetation and structures). Examples of trade-offs and substitutions are those between materials and information (e.g., expediting traffic by electronic controls versus building more roads), between energy and information (e.g., the use of telecommunications to reduce the need for physical travel), between material and energy (e.g., insulation versus heating), between biological energy and machine energy (as between walking and transportation), as well as between biological information--carried and manipulated by humans--and machine information manipulated and processed by computers. However, in a large city it is easy to lose sight that the social and the machine components are projections of the individual and that the individual component of the biosoma--the human--is the ultimate raison d'etre of the city.

The societal component of the city changes continuously and so do the city's machines. But eventually the human component of the bio--the individual--might change also and some machines and biological organisms may combine in new biomachines. This may still be far in the future, but the rapidly expanding cities in the developing world have a better opportunity than the well established cities of the developed world to rethink fundamentally the balance among the three components of the biosoma and their relation to the environment. They can more easily make changes in that balance and avoid the creation of impersonal and alienating environments.

A city acquires different characteristics according to what major themes within the domains of biology, society and machines are emphasized. The leit motivs of traditional industrial cities are materials and energy. Those of the eco-industrial cities which are beginning to emerge, for instance, in Scandinavia, are the balance between biology and machines. The knowledge city is an example of a biosomic city in which information is the leit motif-biological information, as in biotechnology, social information, as in education and in other human services, and machine information, as in computers and other telecommunications devices. Its manifestations include the knowledge parks now beginning to emerge (Bugliarello, 1996).

PRAGMATIC IMPERATIVES AND THE FUTURE

The future of any large urban concentration--and hence its impact on the surface of the Earth--depends on its ability to respond to pragmatic imperatives, reducing potential hazards to its inhabitants, improving livability in its multiple aspects, and being sustainable. These imperatives can only be satisfied if a city is intelligent, ecological and emotionally satisfying. To be intelligent, a city needs to be selfadapting, that is, able to respond and adjust rapidly and adequately to the challenges and opportunities it faces, both internally and on the outside; it needs also to be efficient in the use of resources, in the flexible scheduling of its operations, and in traffic control. An intelligent city stoves to eliminate poverty, with its associated impacts on physical and social health, and pursues the providing of education at all levels as a fundamental tool of efficiency. In effect, being intelligent means that a city is able to address its challenges with new organization and services, by deciding on an appropriate balance between local activities and centralized activities, and by controlling technologies such as the automobile that otherwise can lead to undesirable results, from pollution to congestion to uncontrollable development, as in the case of urban sprawl.

To be sustainable and ecological a city needs, in the first place, to contain its geographical footprint so as to avoid environmentally destructive urban sprawl--a task extremely difficult in well established cities, but still possible in rapidly developing ones. The city needs also to reduce its resources footprint by reducing the pollution and the waste material it generates and by being able to mine its own resources, extracting from within its territory by mining or recycling those materials that have accumulated there in various forms: Being ecological for a city also means reliance on natural means, such as bioremediation, alternative energy sources, and on new concepts in organizing the city, such as balances and tradeoffs among the elements of the biosoma, and development of urban environments that are knowledge-driven(the knowledge city), or driven by the development of more ecological industry operations (the eco-industrial city).

A city is a system of systems in which synergies have to be developed among different goals. For instance, the goal of elimination of slums requires the city to be a system that is caring and emotionally satisfying, as well as efficient and the goal of reducing consumption requires a city to be a system that is efficient and manageable.

TECHNOLOGICAL CHALLENGES

Technology is a key factor in the future trajectory of large urban concentrations, giving them form, purpose and vitality. Technology presents today major new challenges (Bugliarello, 1990; Moss; OECD; Tarr). Several key questions arise in this context, both in the developed and the developing world, but particularly in the latter. For instance, to what extent do totally new systems need to be developed, versus bringing to the cities systems that are only locally new? To what extent should new and older technologies coexist? The older technologies, though less sophisticated, offer at times the large cities of the developing world simpler and more affordable solutions, as in the case of streetcars. The newer technologies, as in the case of cell phones, make it possible to bypass cumbersome and inefficient older systems. Or, to what extent should a large city rely on the locally produced--to which, given the city's scale, it can offer a large local market--versus imported technologies? Also, what kind of standards would be required to facilitate low cost and low maintenance construction, ease of repair, good-enough technologies to enhance local content, to respond to different labor/machines equations than in the high labor cost economies of the highly developed world, and to create products potentially exportable to other urban concentrations, while being socially and environmentally acceptable? Examples of needed technologies in both developed and developing world cities include simpler and cheaper people movers, vehicles with smaller street footprint to alleviate the congestion and parking problem, local energy transformers, and flexible multi modal systems for transportation, water supply and waste removal. Needed technologies for the developing world also encompass simpler sanitation systems, the creation of materials, methods and supplies for self-help, as well as the development of pay-per-use systems, e.g., for energy, water and highway usage, that reduce waste and help financing maintenance and expansion. Major engineering challenges for all cities include relating the built environment to the. natural landscape. Another challenge is to make manageable sub-units of a large city (Bugliarello, 2001).

Many large urban concentrations, as they expand, must reach with their services marginal, peripheral areas without inhibiting their eventual transformation into new; more affluent centers of economic development. There is a need for systems that do not rely completely on rigid trunks, such as a metropolitan railroad or a sewage system, but that extend them at the periphery with flexible, less permanent and cheaper devices that can be replaced eventually with more permanent systems. Especially in the cities of the developing world, infrastructural systems built on the model of those of more affluent and highly industrialized countries are often prohibitively costly.

Addressing these technological challenges can only be successful if the fact is accepted that the city cannot be totally planned, because it is not a machine but a complex bio-socio-machine entity. It can, however, be encouraged to develop in certain directions. New bio-socio-technological conceptions and policies are needed to help guide realistically a large city and avoid freezing, its future in patterns that are unsustainable economically, demographically and environmentally and lead to the neglect of areas and populations within the city because of the inability to serve them. Often, today, urban infrastructures are designed without much thought of how cities will evolve. Rare is the case when a city is planned so as to consider its future growth. Past projections have frequently been faulty, also because they have been based on extrapolation of past data rather than on a systematic analysis of the variables that affect growth.

THE URBANIZATION QUESTION

The ultimate question is whether the extreme urbanization and the very large urban concentration that the globe is experiencing is in the long run good or bad for the species. This multi-faceted question implies issues of both fact and human values in a world increasingly artificial and removed from nature. Is it sustainable if today's rates of consumption of natural resources are reduced? Is it fatally vulnerable? Does it destroy essential human values? At this moment, these questions cannot be answered. But, for that very reason, a better understanding of the phenomenon and of the mechanisms for ameliorating and changing living conditions in cities is that more urgent and important.

The questions subsume a slew of other questions, such as: How do large urban concentrations affect poverty? Will the developing telecommunications systems, from the Internet to satellites to wireless, lessen the need for concentrated human habitats? In an era of exploding telecommunications, will the big urban infrastructural component--highways, bridges, theaters, hospitals, schools, airports--continue to be the glue that binds together a community? Are we irreversibly locked in growing cities? Will expanding cities that sit astride environmental corridors be able to mitigate the great environmental threat that they represent for those corridors? Can the elimination of poverty trigger environmental disasters by enhancing the demands on the environment by a population that has become more affluent? Today, we do not have answers to any of these questions.

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