Introduction

Urbanization has emerged as a major theme in world politics. For the first time on record, the number of people living in urban areas has exceeded the world’s rural population (Satterthwaite et al., 2010: 2809). According to the United Nations, the world’s urban population is projected to grow by another 3 billion people by the year 2050, increasing demand for clean air, water, land and essential public services, and putting unprecedented pressure on these and other resources (McDonald et al., 2011: 1). Most of the growth in urban population is expected to occur in the developing world (Figure 1.1). ²