Although the fact is subject to debate, it would seen that the majority of the world's population has, since 2007, been living in cities rather than the countryside (see Focus 4) and urban zones worldwide are expanding rapidly. This trend can be explained by both a high rate of population growth and an exodus from rural areas that has been accelerating in recent years.
The main part of this urban growth is taking place in the developing countries. Only two of the fifty cities with the highest population density are located in the industrialized countries. Today Tokyo remains the largest city in the world, with more than 33 million inhabitants, but 36 of the 50 most populated cities are to be found in developing or emerging countries, particularly in South-East Asia. Mexico City, with a little more than 17 million inhabitants, is the most populated city in the developing world.
This trend will intensify in the future: among the 100 cities with the highest growth rates, only five are located in industrialized countries: Austin, Atlanta, Las Vegas (United States), Suwon (South Korea) and Bursa (Turkey). The cities that will experience the highest levels of growth are Beihai (China), Ghaziabad (India), Sana'a (Yemen), Surat (India) and Kabul (Afghanistan). Major African cities are also expected to undergo unprecedented expansion: the growth rates of Bamako (Mali), Lagos (Nigeria), Dar es Salaam (Tanzania), Lubumbashi (Democratic Republic of the Congo) and Kampala (Uganda) will surpass 4% per year (see Focus 5).
Major governance challenges stem from this high level of growth. First of all, in terms of housing: the new populations arriving in the cities of the emerging and developing countries are often reduced to living in shantytowns on the city outskirts. The growing demographic pressure on resources will also raise problems of food security (see Focus 10) and access to drinking water. Cities' water and food resources are increasingly limited, yet must be shared among a growing number of inhabitants.
The urban challenge is also linked to climate issues, as most greenhouse gases are emitted in cities that already come under particular threat when located in coastal zones (see Focus 14).
A democratic challenge
Despite signs of international recognition and the increasing influence of urban networks (see Focuses 11 and 12), local authorities remain largely absent from international governance mechanisms, particularly those relating to climate issues. They will, however, have a major role to play in the fight against global warming, not only in helping to reduce it but also by implementing the measures required to adapt to new conditions. On the initiative of the Mayor of Seattle, Greg Nickels, nearly 1,000 American urban agglomerations have undertaken to reduce their greenhouse gas emissions to below their 1990 levels. Today, cities are claiming a seat at the table of the climate negotiations.
In a broader sense, the governance of cities and their representation at the international level is also a democratic challenge: the biggest cities have larger populations than many States, and the scope of responsibility of certain mayors is often very broad. As a result, cities, and especially those located in developing countries, constitute one of the major challenges for world governance, even though they do not at present have an adequate level of representation.
TODAY’S URBAN SPREAD