Since September 2000, when the UN-initiated Millennium Declaration was signed, States have to work towards reducing poverty and encouraging world economic growth in the coming decades (1). In discussions embarked on to respond to these objectives, the questions of population and urban growth take a predominant place. Urbanization, which is a key indicator of current globalization in the world, serves increasingly to predict other trends studied at global scale, like poverty, energy consumption, environment or resources.
The UNO has a demographic data bank, compiled from a mass of information collected from all countries of the world. The organization draws up and publishes regular projections of global urbanization trends (2). These have become an essential source of data and analysis of the urban development process. However, although this work is unanimously recognized as important, research by demographers and geographers arouse criticism of these urbanization projections. These estimations appear to have overestimated the growth of towns for the period in view, particularly for developing countries. West Africa provides an example, as IRD Philippe Bocquier has observed. Researching since 1992 into migration and urbanization in this region, he finds this overestimation to be the result of UN calculation methods for extrapolating shortfalls in data on urban development since the 1950s or for predicting future trends. The UN model, based on a Western concept of urban development, assumes that all countries follow the same pattern of urbanization stages as the most industrialized countries. The model does not always adjust sufficiently for tendencies observed in developed countries. It can also lead to overestimation of the rate and amplitude of the urban densification process in the countries of the South. Philippe Bocquier therefore proposes a different model for processing the data, based on a historical description of the transition from a rural way of life to an urban one. This he does by individual country, seeing that each goes through this change at its own pace. It took Europe and North America two centuries to reach their present degree of urbanization, whereas some countries such as Japan or Taiwan attained a similar level in less than 50 years. This approach moreover allows an assessment of the degree of urbanization of each country according to data available in each case and, in this way, to lessen estimation errors (3).
This new model indicates that, on the global scale, the proportion of individuals living in towns and cities would be 49.2% by 2030, compared with 60.8% estimated by the UN model. This means that the urban population could amount to one billion fewer people than predicted. In 2030 most of the population of developing countries would not be urban: 55.4% of individuals would still live in rural areas. This would especially be the case in Africa (59.5%) and Asia (59.0%) (4). Furthermore, these new estimates suggest that urbanization could reach its saturation threshold more quickly than anticipated (a little after 2030). This theoretical threshold, which represents the maximum urban capacity of a country as a function of its economic development, is reached when the urban transition has finished. Ten large developing countries, with together 18.8% of world population, would alone contribute to more than half the world urban growth between 2025 and 2030. Most countries would already have reached their saturation threshold and would therefore contribute only in a small way to urban growth beyond 2030.
Romain Loury | alfa
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