Metropolitan Growth and Change Research Paper

One concept that embraces this complexity and offers a framework in which to describe and understand both historical and contemporary trends in the urbanization process, at different spatial scales, is the concept of the ‘urban system’ or system of cities. This essay introduces the concept and then uses it to outline recent shifts in metropolitan growth.

1. The Concept of an Urban System

Over the last few decades, it has become widely accepted that individual cities and metropolitan regions do not exist in isolation. Cities, in fact, only exist because of their hinterlands and their interconnectedness to other places. They are, simultaneously, part of several larger sets or networks of urban areas—within a region, a nation and internationally— that interact closely with each other. In other words, they function as nodes in an integrated series of urban systems. Within those systems, individual places assume particular attributes, trade certain goods, and play particular functional roles, because of their relative position in one or other of those systems, and change as the structures of those systems evolve over time.

A system of metropolitan areas is a subset of the urban system that focuses on those larger areas that dominate the national economies and societies and their territorial organization. They are large enough to meet the standard measurement criteria employed by statistical agencies (e.g., in the census of any given country) for metropolitan status. In the US Census, for example, metropolitan statistical areas (MSAs) have a minimum population size of 100,000, with at least 50,000 in their core area municipality. The resulting 280 MSAs, in total, house over 77 percent of the US population and over 50 percent of that population now lives in those MSAs with over one million population. In Europe and Asia similar designations of ‘functional urban regions,’ also intended to replace out-dated political definitions of what is urban, are now widely employed, and they exhibit similar levels of metropolitan dominance.

The logic underlying the idea of studying the urbanization process, both past and present, through a system of urban or metropolitan regions is relatively straight-forward. The first place to look in examining the growth experience of any metropolitan area is to look outside, that is at its relative situation and its external connections or ‘external relations.’ Where does that area fit within the larger systems of which it is a part? The economic fortunes of urban areas, in this framework, are determined by the sum of their networks of linkages, flows and interactions with other places. These linkages, in turn, define and then reenforce the emergence of a hierarchy of urban places, based on systematic differences in size and the range of functions performed, as well as the relative level of diversification of the economy of each urban area, and the mix of populations, occupations and facilities within those places. This interconnectedness, of course, is not new. Historically, the interdependence of urban places has always been an essential feature of the urbanization process. Think, for example, of Carthage as a node in the far-flung colonial urban system of the Roman era, or the extensive networks of relations maintained by cities in the Hanseatic League. What is different now is that the interconnections are more intense, varied and universal.

2. A Brief History of the Idea

The concept of the urban system has been around for some time, but in its current form dates from the 1960s (see Bourne 1974, Berry 1976, Pred 1977, Geyer and Kontuly 1996). It developed primarily out of the need to find a conceptual framework that would overcome the limitations of existing concepts of the urban process that focused narrowly on studies of a few cities or attributes, or one theory. Typically, these included detailed descriptions and classifications of the characteristics of urban areas, but provided little sense of the full range of linkages underlying those attributes. Two principal bodies of urban theories were on offer at the time. The first addressed the location of manufacturing cities, and the structure of their networks of suppliers and markets. The spatial organization and hierarchical properties of the entire urban system, therefore, depended on the specific requirements of the production process alone.

The second dominant paradigm was based on classical central place theory. This theory purported to explain, simultaneously, the size, functions and spatial distribution of urban settlements that had developed primarily to provide different bundles of goods and services to a local, and largely rural, population living in their immediate hinterlands. The assumption that there is a distinct hierarchy of goods and services, varying from low to high-order, each requiring a different threshold size market area to survive, resulted in a settlement system that was also explicitly hierarchical and geographically regular.

Although both theories provided conceptually elegant and analytically rigorous frameworks, each suffered as the economy, settlement structure and the nature of trade and other interdependencies, changed. For example, manufacturing has represented a declining proportion of national output and employment in most western countries, and the location of individual manufacturing firms has been increasingly driven by factors other than minimizing the distance between sources of raw materials, suppliers and markets. At the same time, and despite numerous adaptations, classical central place theory has also become increasingly inadequate as an explanation for urban location and growth in a period of rapid urbanization that is overwhelmingly dominated by large metropolitan areas. These areas provide a wide range of diverse functions for both local and distant populations.

The concept of an urban system then offered an approach to, and a way of thinking about the study of urbanization at a macro-geographical scale, rather than a new technique or theory per se. It became common currency in the field precisely because it was sufficiently robust to accommodate very different levels and patterns of urbanization, and because it overcame the weaknesses and limited utility of models based on only one sector of activity (e.g., manufacturing), or one location factor (e.g., the minimization of transportation costs), or one form of interaction (e.g., the movement of material goods). The central role in the urban systems concept assigned to interactions of all forms also situates the concept in a strategic position to capture the growing importance for urban development of new communications technologies and the information age more generally.

Applying the urban metropolitan system concept does not imply that we should ignore rural areas or small towns or marginalize their role. Instead, the concept argues that in contemporary and highlyurbanized societies, in which (on average) less than 25 percent of populations live outside of metropolitan areas and only 3 percent on farms, the entire economy is effectively ‘organized’ by and through its urban nodes and increasingly by its largest metropolitan regions. In such societies, all parts of national territories can then be considered as ‘urban,’ as integral components of metropolitan regions and the zones of influence surrounding those regions. Rather than being external to the metropolitan economy and social system, rural areas become fundamental building blocks of the regional urban systems associated with each metropolitan area. Even in developing countries with much lower levels of urbanization, the larger metropolitan areas serve as the gateways linking rural areas to the world economy.

In this context, individual metropolitan areas then grow by competing with each other, in order to expand their zones of influence or hinterland. This is the spatial equivalent of attempts to increase (or decrease) market share. The outcome of this competition is a urban system that is spatially differentiated, as well as temporally dynamic. Chicago, for example, garnered tributary territory for itself in the mid-west during the late nineteenth century that was formerly dependent on St. Louis for services and supplies. Denver, Dallas and Minneapolis, in the post-war period, expanded their hinterlands westward, truncating former service areas of Chicago, while Minneapolis’ service area has been reduced in the north-west by the growth of Portland and Seattle. Similarly, in Canada, Toronto has assumed national dominance, in both culture and economy, displacing Montreal from its historical position at the top of the Canadian urban hierarchy, while Vancouver, Calgary and Edmonton have replaced Winnipeg as the gateways to and service capitals for the west.

Perhaps the best recent examples of the increasing importance of inter-metropolitan competition, and the evolution from national to trans-national urban systems, are in western Europe. The creation of the single integrated European market—the European Union—has not only accelerated economic integration across national borders, but is leading to a substantial reorganization of long-established systems of metropolitan centers and hinterlands within each country. All major centers are now competing, intensely and directly, with each other for a larger share of the entire community market, not just for those markets formerly protected within national boundaries and trade barriers.

3. Postwar Phases in the Evolution of Metropolitan Systems

Most scholars, when faced with the daunting task of summarizing the evolution of urbanization, not to mention the complex shifts of functions and influence among metropolitan areas, over the postwar period, tend to rely on constructing periodizations of that history. My own approach is to classify the last half of the twentieth century, admittedly in an overly simplistic fashion, into four periods or phases. Each is characterized by different rates, determinants and geographies of urbanization and by varying trajectories of metropolitan growth. Phase one, encompassing the 1950s and 1960s, was a period of rapid economic and population growth and with it increasing urban and metropolitan dominance. Almost every economic sector, region and urban area grew, floating as it were on the baby-boom population, the expansion of both manufacturing and services, the growth of the public sector, and increasing levels of prosperity and domestic consumption. Some places, of course, grew faster than others, and levels of income ‘polarization’ between regions increased. Most rural areas, and many small towns, in contrast, showed little or no growth; some went into sharp decline. Because of the continuing benefits associated with proximity (or spatial agglomeration), industrial production, wealth and power became even more concentrated in the larger metropolitan areas.

The second phase, beginning in the 1970s, witnessed a marked reversal, or ‘turn-around,’ in the macrogeography of urban growth. Manufacturing activity declined in relative terms and the location of new economic activity shifted away from the older and large industrial metropolises as the benefits of agglomeration declined and the costs rose. In the US, this sectoral shift resulted in a parallel locational shift, as population and employment growth migrated from the old Northeast manufacturing belt (the so-called ‘rust’ belt) to newer cities in the south and west (the ‘sun’ belt). This period is frequently labeled as one of deconcentration and decentralization within national urban systems. Terms such as ‘de-urbanization,’ ‘counter-urbanization’ (Berry 1976) and ‘polarization reversal’ (Geyer and Kontuly 1996), became popular catch-phrases in the literature on urban North America and Western Europe.

During this phase, metropolitan areas in most industrialized countries grew slowly, if at all, and certainly more slowly than middle-size cities and smaller urban centers. Some metropolitan areas registered absolute declines. Population growth reappeared in a few selected rural areas. Net migration flows shifted markedly toward nonmetropolitan regions and, for the first time in the statistical record, more people in North America and in much of Western Europe left metropolitan areas than moved in. To some observers, these trends represented a ‘cleanbreak’ with the past. In effect, it was argued, they spelled the end of the traditional hierarchical ordering of urban places, if not the end of the large industrial metropolis and the reversal of metropolitan dominance. It was also seen as the beginning of a rural and small town revival.

The 1980s, however, produced yet another distinctive pattern of urban growth, and another turn-around in the pattern and hierarchical organization of urban systems. Many, but not all, of the older and larger metropolitan areas showed a rebound in terms of relative growth rates as manufacturing activity underwent a modest renaissance, but especially because service and financial sectors expanded rapidly. Almost all services in the expanding financial and producer services sectors are concentrated in the larger metropolitan areas. The industrial metropolis has, it appears, been supplanted by the service-based or ‘money’ metropolis, and metropolitan dominance has re-asserted itself. The renaissance of small towns and rural areas, on the other hand, seemed to be short-lived. Except for those small towns located in close proximity (i.e., within commuting distance) to metropolitan regions, and a few selected retirement and recreational outposts in locations that are rich in environmental amenities (e.g., warm climate, attractive scenery, cultural and heritage sites), the rural revival was apparently over.

The final phase in this periodization followed the recession of the early 1990s, and continues through to the present. Since this period is still unfolding, it is difficult, indeed premature, to provide a formal label. Nevertheless, as described above, manufacturing activity continues to decentralize, either to outer suburbs or new industrial districts located outside of metropolitan regions, or to countries in the developing world. At the same time, fractions of the ‘new economy,’ in addition to financial and producer services, such as the media and knowledge industries, computer technology, e-commerce and entertainment, have continued to concentrate in the upper levels of the urban hierarchy (e.g., New York, Los Angeles, London, Tokyo). Other functions have tended to locate in smaller centers, but ones that are destined to be the new metropolises of the twenty-first century (e.g., Seattle, Austin, Frankfurt, Barcelona). Thus, even when the hierarchical ordering of metropolitan areas remains more or less intact, the functions performed by those centers and the linkages among them—that is, their network and hierarchical organization and their behavior as a system—have shifted with surprising rapidity.

4. Issues of Current Debate and Research

Current debates focus around a set of questions on how systems of metropolitan areas are being reorganized in response to economic restructuring, social and demographic change, and the increasing global integration of financial markets, production facilities and culture. Both research and policy concerns have shifted from a focus on deterministic economic models and those based on a single sector, to more holistic frameworks that incorporate multiple sectors and a wider range of explanatory variables— including the crucial roles of social capital, institutional capacity and political factors—in accounting for variations in metropolitan growth. Cost effectiveness, rather than cost minimization, and ‘quality of life’ considerations rather than traditional agglomeration factors, have become the critical factors in understanding the location decisions of investors, firms and individuals.

There has also been a shift in research from the effects of economic specialization and agglomeration economies to more flexible paradigms. One example is the re-interpretation of traditional ideas of initial and comparative advantage and the introduction of models of ‘competitiveness’ and innovation (Nijkamp 1990, Mills and MacDonald 1992, Brotchie et al. 1995). Competition between cities is hardly a new idea, as any reading of urban history will confirm, but its nature, intensity and scale are now different. Moreover, the players in this new competitive landscape are not simply individual metropolitan areas (such as San Francisco), but much larger multi-national conglomerates operating out of clusters of metropolitan areas and nearby communities that combined constitute spatially extensive metropolitan regions (e.g., the greater New York region with 20 million people, Los Angeles–San Diego with 16 million, San Francisco–Oakland–San Jose with 10 million).

The shift to a focus on innovation and competitiveness in both the research and policy literature has also heightened awareness of the central importance of two other factors—the capacity of local institutions to adapt to change and the depth of human capital available, the latter embodied in skills, knowledge, local culture and innovative talent—in determining which metropolitan areas grow and which do not. While no one has as yet come up with a simple formula for what determines urban success (although Peter Hall 1998 tries hard to do so), those that grow tend to be those that can stimulate, animate, coordinate, and otherwise take advantage of these skills and knowledge. That is, those places that exhibit the properties of and behave as ‘learning regions’ within the new economy paradigm. Of course, as the urban system concept suggests, they also have to be in a position within the system—i.e., have the external linkages—necessary to take advantage of such attributes.

These debates are perhaps most intense in the recent literature on globalization (King 1990, Sassen 1994, Lo and Yeung 1998). Although this literature is prone to exaggeration on the scale, timing and effects of globalization, often due to the lack of historical perspective, there is little doubt that the process is important. As everyone knows, the global economy has become increasingly integrated and interdependent, especially over the last three to four decades. Trade, transnational travel, tourism, and immigration have increased dramatically. Finance capital now moves around the globe in an instant; manufacturing supply systems are now often global in their reach, with parts designed in one country, produced in another, assembled in still another, and marketed everywhere. Information, including the media and popular culture, have also become ‘internationalized,’ carried by communications systems, managed by multinational media firms, and facilitated by the internet. Interestingly, most of this expanding activity, as in the initial stages of the previous industrial era, is organized by and through the largest metropolitan areas in those countries.

In effect, a new and more tightly interconnected global urban system is developing. This system, ironically, is dominated by financial and cultural world cities such as New York, London, Tokyo and Paris, that have served as ‘command’ centers of the global economy for some time, but now with renewed vigor (Sassen 1991, Knox and Taylor 1995). Below that upper tier are emerging second-order global centers, such as Los Angeles, Hong Kong, Frankfurt, Geneva, Sydney, San Francisco, Singapore, Bombay, Toronto, that jockey for relative position and prominence. Here the competition for status and market share is especially intense, and the rankings of places most fluid. There are, however, a number of problems with the world city hypothesis. One is that it emphasizes attributes rather than networks of external relations. Second, it tends to ignore the inter-connections between all urban places, large and small, within and between nations. In other words, it looks only at the properties and few of the linkages among the top tier cities rather than those linkages among and between all tiers, and at different spatial scales from the regional to the global level. In effect, the world city paradigm lacks the broader and more flexible perspective provided by the urban metropolitan system framework.

All of the larger metropolitan areas are now less dependent on their respective local hinterlands and more dependent on the largest centers and the global market-place. They have, as a result, become more and more detached from their respective ‘national’ urban systems. The global economy, it is widely argued, is now driven more by direct competition among such global urban regions rather than among countries. Nation states, and their governments, are said to be in relative decline, their importance diminished by transnational trade, global corporations and international exchange agreements, while the global urban system is in its ascendency. Western Europe, as an economic space, can now be seen as a ‘continental system of metropolitan regions’ competing amongst themselves for a rich, expanding and (almost) borderless market. Borders still matter, of course, but largely for functions other than defining market share. National governments also still matter, but should be seen as part of a wider ‘rescaling’ or redistribution of economic and political power. Metropolitan areas are now critical agents in this rescaling.

For some observers, the information revolution, new network technologies, and global integration, are combining to rewrite the basis of spatial competition and thus the logic of metropolitan growth. In the extreme scenario, these new parameters are expected to reduce, if not annihilate, the costs (and thus the role) of the ‘friction’ of distance, and to eliminate many of the benefits formerly associated with the concentration of economic activity. A widespread dispersal of economic growth is then feasible, if not more efficient. This, in theory, reduces the need for large urban agglomerations. Does this mean the end of geography, the end of the large metropolis? Do space and place no longer matter? Evidence to date, however, suggests that these claims are at best exaggerated, and weakly documented, and therefore are likely incorrect. The net redistributive effects of information technologies and the rise of global cultural networks, on conditions of metropolitan dominance and polarization are problematic; the same factors can in fact lead to further concentration rather than dispersion, and to a renewed ‘sense of place’ rather than its demise.

While physical distance has declined as a factor in the locational calculus of most economic activities and as a cost in maintaining networks of communication, location itself remains vitally important. In other words, place still matters, and metropolitan places still matter most. It is simply that the elements which define the attributes of space and the value of location today, such as the quality of life and the need for social (and face-to-face) interaction, are weighted differently than in the past. There is no empirical evidence to support the argument that we are doing away with the large metropolis, although some of the former heavily industrial cities (e.g., Detroit, Cleveland, Manchester, Birmingham) that have failed to adapt to the new realities, have certainly declined. Instead, we are expanding many of the traditionally dominant metropolises while rapidly building new ones. In so doing we are reorganizing the metropolitan systems of which they are a part. This is perhaps especially evident in the emergence of global financial centers in Europe and Asia, such as Frankfurt, Singapore, Shanghai and Bombay. Moreover, there is substantial evidence that these metropolitan regions, operating within larger competitive urban systems, rather than nation states, are becoming more central to any explanation of global economic growth, and the diffusion of social and cultural norms.

5. Conclusions

The concept of the urban (now increasingly the metropolitan) system offers a way of approaching, a way of thinking about the macrogeography of the urban process. It stresses the importance of networks of connections among all urban places—that is the summation of their external relations, at regional, national and international scales—and the fact that these places behave as members of several urban systems simultaneously. The complex shifts in the fortunes of individual metropolitan areas documented above suggest the need for such a robust conceptual framework and analytical paradigm. First, the dominant trend identified here is a continuation of metropolitan dominance, although in different forms, and with a somewhat different set of winners and losers. Second, intense competition—both national and global—for a larger share of the economic pie and for cultural dominance, is increasingly seen as competition among a set (a system) of metropolitan regions rather than among national or subnational states. The metropolitan system, writ large, is now the dominant global change phenomenon.

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