chapter  9
36 Pages


In 2000, the world’s population was slightly more than 6 billion. It is anticipated that by

2025 there will be more than 8 billion people living on Earth. Growth will be highest in

less-developed nations. Niger, Yemen, Somalia, Uganda, and Mali, respectively, will

experience the fastest rates of growth.1 This will be coupled with a tremendous growth

of urban environments. In 1900, only 13 percent of the world’s population lived in urban

areas. In 2005, the world’s population reached the tipping point, as 49 percent of people

lived in urban areas. As of 2010, for the first time in world history, more people lived in

urban areas than nonurban areas.2 Existing cities will be transformed; new cities and towns

will emerge. Urban planners, designers, and architects will gain increasing importance,

and they will face a wide array of challenges resulting from rapid economic, technological,

or population growth. Some challenges and responses will be new, while others will have

historical precedents.