| Monograph on the inter-regional exchange and transfer of effective practices on urban management |
For millennia, cities have been centers of culture and crucibles for the advancement of civilization. For as long as there has been human life on the planet, however, the vast majority of the population has lived in tiny settlements, villages, and towns. As the year 2000 approaches, we find ourselves amidst dramatic global transformations that force us to rethink the nature of human settlements. The transformation that is taking place is very complex and touches upon several inter-related issues. Four transformations are presented here to illustrate some important global trends that influence the development of human settlements':
The Four Transformations:
Rural to Urban. The world is becoming predominantly urban. In 1800, 3 percent of the world's population lived in urban areas; in 1950, it was 29 percent. United Nations estimates indicate that in 1990, 43 percent of the world's population lived in urban areas. With the urban population growing two and a half times faster than its rural counterpart, the level of urbanization is projected to cross the 50 percent mark by the year 2005, and the 60 percent mark by the year
2025. Furthermore, United Nations projections indicate that 77 percent of the growth in population over the coming decade will be in the urban areas.
North to South. While cities in industrialized countries face stabilizing or even declining populations, urban population growth in developing countries is dramatic. Estimates predict that from 1950 to 2050, the urban population in third world countries will have increased almost 16 times, from under 200 million to 3.15 billion people. This means that cities in developing countries are expected to grow by 140,000 people a day for the foreseeable future. Given that urban population growth in developing countries is three times that of industrialized countries, by the year 2000 the urban population of developing countries will be almost twice that of developed nations; it will be almost four times as large by the year 2025. Although the absolute level of urbanization and the rates of growth vary among regions within the developing countries, the trend of increased growth is consistent across all of them.
Formal to Informal. This astonishing growth is not equally distributed throughout the urban fabric. Approximately one half of it is due to immigration from the countryside. The vast majority of these migrants also do not have the resources to purchase or rent in the formal housing market. For these reasons, they live in squatter settlements, shantytowns, illegal subdivisions, or tenements in deteriorated and peripheral neighborhoods. Thus, while the formal city may be growing at an average of 3 to 4 percent per year, the informal city is growing at twice that rate. This means that between onethird and two-thirds of the population of third world cities live in various conditions of illegal or irregular settlements.
Cities to Mega Cities. Cities are reaching sizes that are unprecedented in human history. By the turn of the century, there will be 25 cities with populations of 10 million or more, as compared with I city of that size 50 years ago. Worldwide the number of cities comprising 5 to 10 million inhabitants grew from 18 cities in 1970 to 22 cities in 1990. It is expected that by 2010, there will be 33 cities in that population range, and 21 of them will be in developing countries. Of the 26 expected urban agglomerations to have 10 million or more inhabitants by 2010, 21 will be in developing countries: Asia will be home to 14 of these very large cities; 5 will be in Latin America and 2 in Africa. At that population scale, each of these cities holds more people than some 100 individual UN member states today.