The World context

One of the remarkable facts of the twentieth century has been the growing polarisation of population into smaller areas of the earth's surface, particularly towns and cities. Urban centres localise an ever-increasing proportion of the world's population despite its rapid growth. It is estimated by the UN (1989) that between 1975 and 2000 two thirds of all population growth will take place in urban areas, so that while 29% of the world's population in 1950 lived in urban areas, in 1990 about 43% are living in them and by 2000 it will probably be 47%.

More and more of the world's urban dwellers are found in less developed countries (LDCs), which were only 16% urban in 1950, but about 34% in 1990 and will probably be 40% urban by 2000. The annual urban population growth of LDCs has usually exceeded 3.5%, although recently it has declined slightly, while in the more developed countries (MDCs) it has declined markedly from 1.9% in the late 1960s to 0.8% in the late 1980s. Obviously, urban growth in the LDCs has far exceeded the capacity of countries to cope with it: hence the deteriorating conditions in overburdened towns and cities, many of which, like Mexico City, Sao Paulo, Calcutta, Bombay and Shanghai, are among the largest in the world.

Africa presents a particularly poignant example of the problems involved, as it has the fastest population and urban growth in the world as well as the lowest economic development and growth and many of the poorest countries, especially in Tropical Africa.