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This article is about megacities in general. For other uses, see Mega City.
 A megacity is usually defined as a metropolitan area with a total population in excess of 10 million people.[1] Some definitions also set a minimum level for population density (at least 2,000 persons/square km).[citation needed] Megacities can be distinguished from global cities by their rapid growth, new forms of spatial population density, and both formal and informal economy, as well as poverty, crime, and high levels of social fragmentation. A megacity can be a single metropolitan area or two or more metropolitan areas that converge. The terms conurbation, metropolis and metroplex are also applied to the latter. The terms megapolis and megalopolis are sometimes used synonymously with megacity.[citation needed] Megacities are characterized by global connectedness and local disconnectedness. This can be viewed as one of the tensions brought about by the globalization of modern cities. In 2000, there were 18 megacities – conurbations such as Tokyo, New York City, and Mexico City had populations in excess of 10 million inhabitants. Greater Tokyo already has 35 million, which is greater than the entire population of Canada.[2]
[edit] HistoryIn 1800, only 3% of the world's population lived in cities, a figure that has risen to 47% by the end of the twentieth century. In 1950, there were 83 cities with populations exceeding one million; by 2007, this number had risen to 468.[3] If the trend continues, the world's urban population will double every 38 years. The UN forecasts that today's urban population of 3.2 billion will rise to nearly 5 billion by 2030, when three out of five people will live in cities.[4] This increase will be most dramatic on the least-urbanized continents, Asia and Africa. Surveys and projections indicate that all urban growth over the next 25 years will be in developing countries.[5] One billion people, one-sixth of the world's population, now live in shanty towns,[6] which are seen as "breeding grounds" for social problems such as crime, drug addiction, alcoholism, poverty, poor family planning, and unemployment. In many poor countries overpopulated slums exhibit high rates of disease due to unsanitary conditions, malnutrition, and lack of basic health care.[7] By 2030, over 2 billion people in the world will be living in slums.[8] Over 90% of the urban population of Ethiopia, Malawi and Uganda, three of the world's most rural countries, already live in slums. By 2025, according to the Far Eastern Economic Review, Asia alone will have at least 10 megacities, including Jakarta, Indonesia (24.9 million people), Dhaka, Bangladesh (26 million), Karachi, Pakistan (26.5 million), Shanghai (27 million) and Mumbai (33 million).[9] Lagos, Nigeria has grown from 300,000 in 1950 to an estimated 15 million today, and the Nigerian government estimates that the city will have expanded to 25 million residents by 2015.[10] [edit] Largest cities[edit] GrowthFor almost a thousand years, Rome was the largest, wealthiest, and most politically important city in Europe.[11] Rome's population passed a million by the end of the 1st century BC.[12] Its population declined to a mere 20,000 during the Early Middle Ages, reducing the sprawling city to groups of inhabited buildings interspersed among large areas of ruins and vegetation. Baghdad was likely the largest city in the world from shortly after its foundation in 762 AD until the 930s, when its population was matched by Córdoba.[13] Several estimates suggest that the capital of the Islamic Empire contained over a million inhabitants at its peak.[14] The medieval settlement surrounding Angkor, the one-time capital of the Khmer Empire which flourished between the 9th and 15th centuries, could have supported a population of up to one million people.[15] In 1950, New York City was the only urban area with a population of over 10 million.[16] Geographers had identified 25 such areas as of October 2005,[17] as compared with 19 megacities in 2004 and only nine in 1985. This increase has happened as the world's population moves towards the high (75–85%) urbanization levels of North America and Western Europe. The 1990 census marked the first time the majority of US citizens lived in cities with over 1 million inhabitants. In the 2000s, the largest megacity is the Greater Tokyo Area. The population of this urban agglomeration includes areas such as Yokohama and Kawasaki, and is estimated to be between 35 and 36 million. This variation in estimates can be accounted for by different definitions of what the area encompasses. While the prefectures of Tokyo, Chiba, Kanagawa, and Saitama are commonly included in statistical information, the Japan Statistics Bureau only includes the area within 50 kilometers of the Tokyo Metropolitan Government Offices in Shinjuku, thus arriving at a smaller population estimate.[18][19] A characteristic issue of megacities is the difficulty in defining their outer limits and accurately estimating the populations. The twenty-five largest megacities, according to these criteria are:
Source: Th. Brinkhoff: The Principal Agglomerations of the World, 2009-02-27 Another list defines megacities as urban agglomerations instead of metropolitan areas.[21] As of 2007, there are 22 megacities by this definition. [edit] Emerging Megacities
United Nations projections indicate a steady downturn in the emergence of new megacities after 2005. However, the expansion and merging of highly-urbanized zones (megalopolises) may remain an important trend, as typified by the following:
Emerging megacities in China (in decreasing order of population):
Emerging megacities in India (in decreasing order of population):
Emerging megacities in Pakistan (in decreasing order of population):
[edit] Challenges
The world’s population of “slum” dwellers increases by 25 million every year. The majority of these numbers come from the fringes of urban margins, located in legal and illegal settlements with insufficient housing and sanitation. This has been caused by massive migration, both internal and transnational, into cities, which has caused growth rates of urban populations and spatial concentrations not seen before in history. These issues raise problems in the political, social, and economic arenas. These record-setting populations living in urban slums have little or no access to education, healthcare, or the urban economy. [edit] Regional uses of the term Megacity[edit] CanadaIn Canada, the 1990s saw the forced amalgamation of several municipal entities in the provinces of Nova Scotia, Ontario and Quebec into larger new municipalities. The process created what was labeled a megacity by the media, although none of the created municipalities fit in the definition of a megacity in the international sense and some of them have fewer than a million inhabitants. The city of Winnipeg was similarly amalgamated in 1971, although the word unicity is used more commonly than megacity to describe that particular amalgamation. [edit] Nova Scotia
[edit] OntarioSee also: Common Sense Revolution
[edit] QuebecSee also: Municipal reorganization in Quebec
[edit] In fiction
[edit] See also
[edit] Notes
[edit] References
[edit] External links
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