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Report n°1: The new constraints of urban development

Influence of the level of development on the urbanisation process

Any attempt to consider the nature of urban development requires a clear distinction to be drawn between the developed and developing world.

In developed countries, we can observe a modest level of quantitative urban development but a clear and significant level of qualitative urban development. The former is modest since there is zero growth in the population flow to urban areas. The roots of this situation lie in the depletion of the sources of urban population growth: the general population growth and migration from the country to the city. Since 80% of the population already lives in urban areas, the countryside no longer represents a population pool. It should be pointed out that in certain countries immigration may play an important quantitative role but this is not currently the case for Europe generally.

Urban areas are, however, undergoing considerable qualitative development and changing before our eyes in line with three major trends. Firstly, there has been an increase in the number of square metres required by each temporary or permanent inhabitant or worker. In addition, obsolete infrastructure is undergoing renewal. Merely examining the stocks does not enable accurate interpretation of the flows. Finally, we are seeing increasing movements between population centres or within each population centre.

However, given the increase in this new type of mobility, there is a tendency to exaggerate the scale of urban sprawl. According to a certain definition of sprawl, France has not experienced this phenomenon in the past decade (except for the Paris area). In percentage terms, the increase in the population in the centre was on a par with that of the population in outlying areas (see the article by Rémy Prud'homme and Bernard-Henri Nicot: Urban sprawl in France in recent decades, July 2002).

Even in the United States, there has been no de-population of urban centres but a marked process of impoverishment. Today, the population in such urban centres is stable but more affluent populations are returning alongside new, primarily Asian, migrants who are bringing in higher incomes. In numerous French cities, it can be seen that the level of incomes in the centre is lower than in the inner suburbs (with the notable exception of Paris), which reflects a relative impoverishment of the centre.

The situation is markedly different in developing countries where there has been a sharp drop in incomes in city centres resulting in inner city urban decay. Above all, there has been a steep rise in city populations.

Today, demographic analysis by most international organisations indicates that there are 70 million new urban-dwellers each year, a large proportion of whom live in developing countries. We have now crossed the threshold of 50% of the world population living in cities and it is forecast that two-thirds of the population will live in cities by 2025.

At this level, three observations need to be made as regards the growth of cities in developing countries.

Firstly, it should be noted that there are major disparities from one country to the next. It is therefore impossible to talk in general terms about population growth (China, where the population is relatively stable, differs radically from Africa) or the rural population pool (enormous differences exist between India, where the urban population only represents 30% of the total population, and Africa or China, on the one hand, and Latin America, which is heavily urbanised, on the other).

It should also be remembered that the rapid urbanisation of developing countries is a transitory and non-exponential phenomenon. The urbanisation curve necessarily has a logistical pattern with a period of rapid urban growth which varies between 10 and 30 years.

Finally, it can already be noted that it is no longer the very large cities which are developing fastest. Most urban growth is now occurring in cities with 100,000 to one million inhabitants.