By 2006, half of the world's population (3.2 billion people) will be living in urban areas, and most of the growth will occur in developing countries. A great majority of the urban population (over 80%) lives in medium-sized cities and towns, and not in the world largest cities. Mitigating strategies must therefore address the specific problems occurring in these medium-sized cities.
Market in Ounanaminthe, Haiti (Photo: Peter Messerli)
Key problems of urbanisation in developing and transition countries are uncontrolled growth, lack of infrastructure, environmental pollution, human health impacts, social reorganisation, new poverty, housing in general, and lack of legal structure (cf. Bolay et al., 1999).
Urban agriculture offers an economic opportunity for many urban dwellers. At present, 800 million urban farmers harvest 15 percent of the world's food supply. However, settlement density, waste and agricultural inputs, and the many possible contamination chains pose a further challenge to urban development.