ABSTRACT
Cities are becoming the most dominant location of people on the earth. The United Nations predicts that 5 billion people will live in cities by 2030, up from 3.3 billion in 2007, with the change being particularly dramatic in Asia and Africa. This chapter examines urban ecology and urban sustainability by looking at the ecology of cities, their use of energy, their spatial heterogeneity, and how they structure the behavior of the inhabitants. It explores how cities have changed through history. The relationship of the physical environment and cities has been of interest from the beginning of social theory. Historically, European cities have been more compact and dense than American cities. European cities have good public transit, are walkable, and are less reliant on the automobile. Cities have grown by accelerating economic activity and the circulation of capital, without giving much thought, until recently, to the costs of pollution.
