ABSTRACT

Urban areas have experienced dramatic changes in both population and spatial extent over the past 50 years. More than 50% of the world’s population now lives in urban and suburban areas (UNFPA 2007). According to the UN Wall Chart of Urban and Rural Areas (https://www.unpopulation.org), the world’s urban population was estimated at 3.29 billion in 2007 and was expected to rise to 6.4 billion by 2050. The rural population was anticipated to decline slightly from 3.37 billion in 2007 to 2.79 billion in 2050. In 2007, 49% of the world’s population lived in urban areas. The world’s urban population reached 49.4% in 2007, resulting in more urban residents than rural residents in the world. The proportion of the world population living in urban areas is expected to rise to 69.6% by 2050. Much of the growth is occurring in the developing countries, where urban developments are significant. The speed and the scale of this growth continues to pose formidable challenges to individual countries as well as to the world community. Figure 1.1 illustrates variations of world population between 1950 and 2050 (United Nations 2012). Associating with these population changes are large and complex economic, social, political, and demographic changes, including the multiplication in the size of the world’s economy and a shift in economic activities and employment structures from agriculture to industry and services.