Over half the world’s population is now concentrated in towns. In 1950, it had not yet reached 30%, but in 2007 the rate of urbanisation hit the 50% mark. According to the United Nations, urban populations are expected to represent just under 60 % of the total by 2030 . Today, there are 3.3 million city-dwellers, four and a half times than there were in 1950. In 2030, the urban population is expected to reach 5 billion, as many people living in cities then as there were planet-wide in 1987.
Africa and Asia: less urbanised than other continents
Urbanisation has taken place more or less rapidly depending on the continent. The most developed regions like Europe and North America are also more urbanised, with three-quarters of the population living in towns; however in comparatively less developed Latin America, the urbanisation rate is also high (78%). In contrast, Africa and Asia still have predominantly rural populations. However, urbanisation is increasing and city-dwellers are expected to outnumber the rural population by 2030. It is on these continents, which have the biggest populations, that the majority of mega-cities are likely be located.
Although the urbanisation level in Asia remains relatively low, the continent accounts for three-fifths of the world’s human population, and holds over half of the world’s urban population. China and India alone account for over a quarter of the global population.
From 1950 to 2005, annual urban population growth remained below 1.4 % in industrialised countries but stood at over 3.6 % in developing countries. In Africa, urban growth was fastest– 4.3% a year on average – while in Europe it was slowest – under 1.2 %. In Asia and Latin America, urban growth was also intense, respectively reaching 3.4 and 3.3 % over the same period. […]
Large cities are multiplying and increasingly dense
Size is a defining characteristic of cities: the term ‘urban’ can be applied to medium-sized cities or urban agglomerations of over 10 million inhabitants, even if the ways of life there can differ greatly.
The percentage of the urban population living in agglomerations with 500,000 to 10 million inhabitants varied very little between 1975 and 2005, but the number of these cities doubled from 420 to 849 in 30 years. Moreover, each sub-category generally doubled in number too, from agglomerations with 500,000 to 1 million inhabitants, to those with 1-5 million or 5-10 million inhabitants.
According to the 2005 United Nations revision,, 20 urban agglomerations held over 10 million inhabitants in 2005. Although this includes Tokyo, which is located in a developed country – the majority of these agglomerations were actually located in developing ones. China and India, where the urbanisation rate is slower than the average in developing countries, are home to two and three of the world’s largest cities respectively: Shanghai and Beijing in China and Mumbai, New Delhi and Calcutta in India.
Does demographic growth drive urban growth?
Developing countries are all experiencing stronger urban growth today. Rapid urbanisation is generally seen as one of the consequences of strong population growth. Urban growth is driven directly by internal urban growth and indirectly by the rural exodus, a phenomenon arising from ever growing demographic pressure in the countryside. Over four-fifths of variations in the urban population growth rate are consistent with total population growth.
The rapid urbanisation of developing countries could also stem from a correction effect in these countries, where urban growth has lagged in the past. However, a comparison of long-term urbanisation growth rates in the Unites-States and India shows that in India, the urban population grew later and at a considerably slower pace than in the U.S. .
Does urbanisation hinder development?
Nathan Keyfitz  found it difficult to envisage economic, political and social development in the countryside without cities. Paul Bairoch similarly found a strong correlation between urban expansion and the “progress of civilization”, but went on to consider that positive interaction between urbanisation and economic development – one of mutual strengthening – did not apply to developing countries today . This economics historian described urbanisation in developing countries as “urban inflation”. While it is very easy to single out problems in cities – particularly those in poor countries – from public transport and infrastructure inadequacy to housing shortages, it is harder to know for sure whether it is urbanisation itself which hampers development. In the poorest countries, where the urbanisation is still rapid, urbanisation may well have become independent of economic growth. In other words, migration to towns occurs completely independently of urban labour market needs. Since the growth of cities is also partly due to a higher number of births to deaths, lower urban development holds back demographic transition and encourages a higher urban birthrate.
The challenges that newcomers to cities face in terms of social integration, particularly in Africa, are well-documented. Difficulties range from access to work and housing, to the problems of establishing relationships. Congestion problems in the large cities of developing countries, rising pollution levels and expanding slum populations – where a third of city-dwellers are thought to live – are all factors that seem to signal a conflict between urbanisation and development.
Cities in some industrialized countries are also thought to be in a state of crisis. Suggested evidence of this is the social exclusion and spatial segregation of a growing number of people living in highly precarious conditions or experiencing marginalisation. However, do these problems just concern cities, or are certain aspects simply more ‘visible’ in urban areas where populations are more concentrated? To what extent are ghettos in the United States or Paris a specifically urban problem? In Jacques Donzelot’s words, “social problems encountered in some urban areas prove that cities have problems, not that cities are the problem” .
The world will become increasingly urban over the coming decades. By 2030 however, over 3 billion people will still live in the countryside.. A real rural-urban balance, especially to halt or at least control rural migration, is often called for but what this might mean has never really been explained. For example, eliminating the “urban advantage” offered by the public facilities in cities that make life easier is unrealistic because city-dwellers wield greater political clout as cities expand. The ever-widening disparities between town and country, for example in terms of access to water and electricity, differ from country to country, but overall, rural areas always lose out where these types of services are concerned. In order to promote sustainability of the countryside – by limiting the departure to cities – and in the interests of equity, rural areas must ensure that development does not pass them by.
 United Nations – World Population Prospects. The 2006 Revision, United Nations, New York, 2007 (http://esa.un.org/unpp/)
 Jacques Véron – “L’urbanisation du monde”, Paris, published by La Découverte, 2006
 Nathan Keyfitz – “International Migration and Urbanisation”, in Resources and Population, Colombo B., Demeny P. and Perutz M. f. (eds), Oxford, Clarendon Press, pp. 269-285, 1996
 Paul Bairoch – “Cinq millénaires de croissance urbaine” in “Quelles villes, pour quel développement?”, project editor: Ignacy Sachs, Paris, published by PUf, pp. 17-60, 1996
 Jacques Donzelot – “La nouvelle question urbaine” published by Esprit, November 1999, pp. 87-114
 National Research Council – Cities transformed: Demographic Change and its Implications in the Developing World, M. R. Montgomery, R. Stren, B. Cohen, and H. E. Reed (eds), The National Academy Press, 2003
Jacques Véron (INED)
Population et sociétés magazine, No.435, June 2007