ABSTRACT
As we enter the 21st century, the world is becoming increasingly urban, both in terms of human population and the Earth’s surface. Although cities have existed for centuries, the urbanization processes today are different from urban transitions of the past in three significant ways (Cohen, 2004). First, the magnitude of urbanization is extraordinary. The global proportion of urban population was a mere 13% in 1900 (UN, 2006). It rose gradually to 29% in 1950. By 2030, the world’s urban population is expected to nearly double from 2.86 billion in 2000 to almost 5 billion (Figure 1.1). There are now 400 cities with populations of 1 million or greater, compared with only 16 cities with populations of 1 million or greater at the turn of the 20th century. The scale of urban land area is also extraordinary. Neoliberal reforms, demographic transitions, and economic development have created new cities and megapolitan regions of extraordinary size. The two biggest metropolitan regions, New York and Tokyo-Yokohama, together encompass an area of greater than 15,000 km2, an area the size of one and one-half Jamaicas.
