Urbanization is the study of the social, political, and economic relationships in cities, and someone specializing in urban sociology would study those relationships. Urban areas are cities, towns, and other places where people live in a compact population. Most urban people are engaged in economic activities that function efficiently in dense populations, such as commerce, education, manufacturing, and services. In contrast, resource-based economic activities, such as cultivating food and harvesting minerals, fossil fuels, timber, or wildlife, occur primarily in rural areas. There is no strict dividing line between rural and urban; rather, there is a continuum where one bleeds into the other. However, once a geographically concentrated population has reached approximately 100,000 people, it typically behaves like a city regardless of what its designation might be.
Urban areas import energy, food, and materials from the local countryside, as well as from more distant regions of their country, in addition to other nations around the world in an increasingly global commerce. The resource-related connections between cities and rural areas exist at all spatial scales (local, regional, and global) and are an integral but often insufficiently appreciated aspect of urban ecology.
The development of dense habitations (initially small villages) during human cultural evolution began about 10-thousand years ago, when early agricultural practices allowed the production of local surpluses of food (harvests that exceeded the subsistence needs of the farmers themselves). The excess food encouraged the development of specialized occupations that were most efficiently performed in a central place such as a village or town. New societal activities included organized religion and political systems, artisanal manufacturing, and the means of administering these over wide areas through hierarchical economic, political, religious, and military structures.
The first villages were probably supported by both settled agriculture and local hunting-and-gathering activities. By about 9,000 years ago, small farming villages were relatively widespread in some regions, particularly in the Fertile Crescent of the Middle East (see Chapter 24). By 8,500 years ago, that region boasted sizeable walled towns. Similar developments also occurred in China and probably elsewhere in southern Asia.
Most scholars agree that the first cities were developed somewhere in ancient Mesopotamia, though there are disagreements about exactly where. Most early cities were small by today’s standards, and the largest city around 100 CE was most likely Rome, with about 650,000 inhabitants. The factors limiting the size of ancient cities included lack of adequate sewage control, limited food supply, and immigration restrictions. For example, serfs were tied to the land, and transportation was limited and inefficient. Today, the primary influence on cities’ growth is economic forces.
Growth of Urban Populations
In 1750, few cities supported more than 50-thousand people – London was the only one in England, and there were none in North America. In 1830, New York and Philadelphia were the only American cities with a population greater than 100-thousand. By 1910, however, 52 cities in North America supported more than 100-thousand people (New York was the largest, with more than 1 million). In 1950, New York and Tokyo were the only two megacities in the world (that is, having a population greater than 10 million). In 2014, there were 537 cities supporting more than 1 million people, including 35 megacities, of which 29 were in the developing world (Brinkhoff, 2015).
Urbanization levels are affected by two things – migration and natural increase. Migration is the movement of population from one area to another. Some migrations are forced, voluntary, permanent and temporary, international and regional. Rural to urban migration, is the movement of people from countryside to city areas. This type of migration happened in developed countries from the 18th century onwards on a large scale, and has gradually slowed down. However, many developing countries are experiencing massive rural to urban migration, mainly of young males, into the major cities.
As was the case in North America, other urban centers experienced a growth spurt during the Industrial Era. In 1800, the only city in the world with a population over 1 million was Beijing, but by 1900, there were 16 cities with a population over 1 million. The development of factories brought people from rural to urban areas, and new technology increased the efficiency of transportation, food production, and food preservation. For example, from the mid-1670s to the early 1900s, London increased its population from 550,000 to 7 million. The growth in global urbanization in the 20th and 21st centuries is following the blueprint of North American cities, but is occurring much more quickly and at larger scales, especially in peripheral and semi-peripheral countries. Shanghai almost tripled its population from 7.8 million to 20.2 million between 1990 and 2011, adding the equivalent of the population of New York City in 20 years. It is projected to reach 28.4 million by 2025, third in size behind Tokyo (38.7 million) and New Delhi (32.9 million).
The major reasons for migration can be classified into push and pull factors. A push factor is something that can force or encourage people to move away from a country. Push factors can include famine (as in Ethiopia in the 1980s), drought, flooding, a lack of employment opportunities, population growth, over population, and civil war. A pull factor is one in which encourages people to move to a city. Pull factors include the chance of a better job, better access to education and services, a higher standard of living. These factors have contributed to millions of people in developing countries moving to cities, creating mass urbanization. Natural increase (a population increase due to more births and fewer deaths) also has a major effect on rates of urbanization. Natural increase is stimulated by better access to medical care, improved water supplies, sanitary conditions and wealth.
Suburbs and Exurbs
As cities grew and became more crowded (and often more impoverished and costly) more and more people began to migrate back out of them. But instead of returning to rural small towns (like they had resided in before moving to the city), these people needed close access to the cities for their jobs. In the 1850s, as the urban population greatly expanded and transportation options improved, suburbs developed. Suburbs are the communities surrounding cities, typically close enough for a daily commute in, but far enough away to allow for more space than city living affords. The bucolic suburban landscape of the early 20th century has largely disappeared due to sprawl.
Urban sprawl contributes to traffic congestion, which in turn contributes to commuting time. Commuting times and distances have continued to increase as new suburbs developed farther and farther from city centers. Simultaneously, this dynamic contributed to an exponential increase in natural resource use, like petroleum, which sequentially increased pollution in the form of carbon emissions (negative aspects of urban sprawl will be explored further in the following section).
As the suburbs became more crowded and lost their charm, those who could afford it turned to the exurbs, communities that exist outside the ring of suburbs and are typically populated by even wealthier families who want more space and have the resources to lengthen their commute. It is interesting to note that unlike U.S. cities, Canadian cities have always retained a fairly large elite residential presence in enclaves around the city centres, a pattern that has been augmented in recent decades by patterns of inner-city resettlement by elites (Caulfield 1994; Keil and Kipfer 2003). As cities evolve from industrial to postindustrial, this practice of gentrification becomes more common. Gentrification refers to members of the middle and upper classes entering city areas that have been historically less affluent and renovating properties while the poor urban underclass are forced by resulting price pressures to leave those neighbourhoods. This practice is widespread and the lower class is pushed into increasingly decaying portions of the city.
Urban Ecosystems
Any urbanized area can be viewed as being an ecosystem, because it has the following ecological attributes:
- a need for enormous inputs of energy and materials to sustain its human population and its diverse economic activities, and to maintain its structure and grow
- a complex metabolism, including well-developed webs of transfer, processing, and storage of materials, energy, and information among interacting organisms and economic sectors
- and immense outputs of heat and other waste materials, which are disposed of in surrounding ecosystems, causing pollution and other environmental problems
Of course, the habitats of cities and towns are very strongly influenced by human activities. Collectively they comprise an urban–industrial techno-ecosystem. Although humans are the dominant species in the urban ecosystem, many other species are also supported, most of which are not native to the region. The structure of this anthropogenic ecosystem is dominated by the businesses, dwellings, factories, roads, and other infrastructure of the human economy, while also supporting manicured green space as well as remnants of natural habitats in parks and other less-developed spaces. Even parking lots, sidewalks, and industrial areas, which from an ecological perspective are extremely degraded habitats, do manage to support some biodiversity. Important ecological functions also occur within the urban ecosystem, such as biological productivity and water and nutrient cycling, but these processes are greatly influenced by humans. Still, some urban places are relatively natural in character and are maintained in this condition as parks. Some prominent examples of “natural-area parks” include Stanley Park in Vancouver; a series of parks along the Bow River in Calgary and on the North Saskatchewan River in Edmonton; Assiniboine Park in Winnipeg; High Park and Hanlan’s Point in Toronto; Bois de Liesse in Montreal; Point Pleasant Park in Halifax; and Signal Hill in St. John’s. These greenspaces are remnants of natural habitat that have survived the urbanization process, and they contain ecological communities that are mostly dominated by native species.
All urban areas are intrinsically dependent on surrounding ecosystems to provide them with necessary resources and to assimilate wastes that are generated. The ecological footprint (or eco-footprint) of an urban population is the area of ecoscape (landscape and seascape) that is needed to supply the necessary food, energy, materials, waste disposal, and other crucial goods and services. As a global average, the average human has an eco-footprint of about 2.7 hectares, but there are only 1.8 ha of bio-productive land and water on Earth (Ewing et al., 2010). This means that the human enterprise has already overshot global bio-capacity by 30%, and is now operating on an unsustainable basis by depleting the remaining stocks of “natural capital”. Note that, in the context of ecological footprints, these data are measures in “global hectares” (gha), which represent the average productivity of all bio-productive habitats on Earth or in a country, including agricultural land, forests, and fishing grounds, but not including desert, glaciers, or the open ocean.
An average Canadian has an ecological footprint of about 7.3 global hectares (2007 data; Ewing et al., 2010). This is the seventh-most intensive national per-capita footprint in the world, after the United Arab Emirates (10.7 gha), Qatar (10.5 gha), Denmark (8.3 gha), Belgium (8.0 gha), the United States (8.0 gha), and Estonia (7.9 gha). Here are some additional comparisons among wealthier countries: Australia (6.8 gha), Kuwait (6.3 gha), Ireland (6.3 gha), Norway (5.6 gha), France (5.0 gha), Germany (5.0 gha), United Kingdom (4.9 gha), and Japan(4.7 gha). The rapidly-growing economies include Russia (4.4 gha), Brazil (2.2 gha), China (2.2 gha), and India (0.9 gha). Of course, people living in poorer countries have much smaller ecological footprints: Afghanistan (0.6 gha), Bangladesh (0.6 gha), Haiti (0.7 gha), Burundi (0.9 gha), Ethiopia (1.1 gha), Vietnam (1.4 gha), and Peru, (1.5 gha).
Urban Planning
Urban ecosystems have extremely complex structures and functions (although not more so than natural ecosystems). To some degree, their development has occurred in an orderly fashion, with certain areas being designated for particular kinds of structures and activities. Urban planning is the active process of designing and organizing the structure and function of cities. As such, urban planning contributes to the information needed by legislators and other decision makers as they develop sensible and efficient siting of the following:
- buildings, including homes, commercial properties, institutions (such as hospitals and schools), and industrial facilities
- infrastructure for transportation, utilities, and waste management, such as roads, railways, public-transit routes, electrical transmission and pipeline corridors, sewers and sewage-treatment facilities, and solid-waste disposal areas
- greenspaces, including playing fields and horticultural and natural-area parks
Well-planned urban areas have relatively pleasant neighborhoods where people live and work. In contrast, poorly planned cities are chaotic, dirty, and unpleasant. In general, urban planning is most effective in wealthy developed countries such as Canada, but much less so in poorer developing countries where the population is growing and urbanization is proceeding most rapidly.
The dominant planning paradigm of the past 60 years has involved the segregation of major land-uses and economic activities into different areas. This kind of strategy has greatly influenced the design of modern cities, including all those in Canada. It has resulted in many urban people living in discrete inner-city neighborhoods or more distant suburbs, while shopping in large malls, working in factory or office complexes and industrial parks, and commuting long distances among these land-use types. However, this type of planning has contributed to some important urban problems, including the following:
- the rapid growth of huge, multi-city, urbanized regions (sometimes known as conurbations)
- the inefficient segregation of residences from places of work and commerce
- long commuting times for workers
- congested transportation systems
- a decay of neighborhood life
- environmental problems such as air and water pollution, wasteful use of energy and materials, paving of valuable farmland (many urban areas are located on excellent agricultural land), and losses of natural habitat
The paradigm of widely segregated land-use is now being challenged by the concept of a more integrated “neighborhood” design. This involves the development of relatively compact, self-sufficient communities that contain a mixture of residential and commercial land-uses. In some respects, this harkens back to more traditional elements of community design, in which housing, employment, local commerce, small-scale manufacturing, and recreation were all within easy walking distance. The re-emergence of this concept in urban planning has been substantially influenced by the ideas of Jane Jacobs, a geographer who taught at the University of Toronto.
References Cited and Further Reading
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Environment Canada. 1996. The State of Canada’s Environment. Government of Canada, Ottawa, ON.
Environment Canada. 1999. Air Quality Trends in Canadian Cities, 1979–1992. Ottawa, ON: State of the Environment Reporting, Environment Canada. https://web.archive.org/web/20010214040646/http://www.ec.gc.ca/pdb/uaqt/aqfact_e.html
Environment Canada. 2007. Municipal population served by wastewater treatment. State of Environment Infobase Ottawa, ON. https://web.archive.org/web/20040621114650/http://www.ec.gc.ca:80/soer-ree/English/Indicators/Issues/Urb_H2O/Bulletin/uwind3_e.cfm
Environment Canada. 2014. Air Quality Indicators. Environment Canada, Ottawa, ON. http://www.ec.gc.ca/indicateurs-indicators/default.asp?lang=en&n=7DCC2250-1
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Attribution
Modified by Kyle Whittinghill from the following sources:
