Urbanization and Environment
The US model of metropolitan growth is driven by a loosely regulated real estate market and conspicuous consumption of land, building materials, and privately owned vehicles. It is premised on the seemingly unlimited availability of capital, energy resources and land.
(Angotti, 1995, p. 635).
North America is the only continent where the majority of the population lives in metropolitan areas. In the United States, 87% of the population lives in metropolitan areas and their hinterlands (Golden, 1981; Angotti, 1995; fig. 24.1). Infilling between cities has resulted in the development of major megalopolises, such as the Philadelphia, Boston, Washington, D.C., New York urban corridor. This pattern of urbanization has had major environmental impacts, both within urban areas themselves and throughout much larger zones of influence. Urban development has altered local and regional climates, and has degraded surface and groundwater quantity and quality, and the ecosystems. Although there have been severe impacts at a range of scales, management initiatives in recent decades have reduced or curbed current impacts through regulation and voluntary measures. There has also been growing emphasis on reducing future impacts through environmentally sensitive urban planning.
The extent and range of environmental impacts due to urbanization in North America are closely related to the continent's unique history of urban growth. Modern North American urban centers began to develop after European settlement and the emergence of colonial economic systems. Early nineteenth-century North American cities operated mainly as commercial centers that supplied primary products to markets outside the continent, and received finished goods, capital, and labor in return. However, by the mid-1800s, national urban systems emerged, domi-