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Tokyo, the largest megacity

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]}

In 2000, there were 18 megacities – conurbations such as Mumbai^[2], 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.^[3]

History

In 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.^[4] 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.^[5]

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.^[6] One billion people, one-sixth of the world's population, now live in shanty towns,^[7] 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.^[8] By 2030, over 2 billion people in the world will be living in slums.^[9] 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 Mumbai (33 million), Shanghai (27 million), Karachi, Pakistan (26.5 million), Dhaka, Bangladesh (26 million) and Jakarta, Indonesia (24.9 million people).^[10] 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.^[11]

Largest cities

Growth

For almost a thousand years, Rome was the largest, wealthiest, and most politically important city in Europe.^[12] Rome's population passed a million by the end of the 1st century BC.^[13] 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.^[14] Several estimates suggest that the capital of the Islamic Empire contained over a million inhabitants at its peak.^[15] Chinese capital cities also experienced huge population booms during prosperous empires.

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.^[16]

In 1950, New York City was the only urban area with a population of over 10 million.^[17] Geographers had identified 25 such areas as of October 2005,^[18] 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.^[19][20] 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:

Rank	Megacity	Country	Continent	Population	Annual Growth
1	Tokyo	Japan	Asia	34,000,000	0.60%
2	Seoul	South Korea	Asia	24,200,000	1.40%
2	Guangzhou	China	Asia	24,200,000	4.00%
4	Mexico City	Mexico	North America	23,400,000	2.00%
5	Delhi	India	Asia	23,200,000	4.60%
6	Mumbai (Bombay)	India	Asia	22,800,000	2.90%
7	New York City	USA	North America	22,200,000	0.30%
8	São Paulo	Brazil	South America	20,900,000	1.40%
9	Manila [21]	Philippines	Asia	19,600,000	2.50%
10	Shanghai	China	Asia	18,400,000	2.20%
11	Los Angeles	USA	North America	17,900,000	1.10%
12	Osaka	Japan	Asia	16,800,000	0.15%
13	Kolkata	India	Asia	16,300,000	2.00%
14	Karachi	Pakistan	Asia	16,200,000	4.90%
15	Jakarta	Indonesia	Asia	15,400,000	2.00%
16	Cairo	Egypt	Africa	15,200,000	2.60%
17	Moscow	Russia	Europe	13,600,000	0.20%[citation needed]
17	Beijing	China	Asia	13,600,000	2.70%
17	Dhaka	Bangladesh	Asia	13,600,000	4.10%
20	Buenos Aires	Argentina	South America	13,300,000	1.00%
21	Istanbul	Turkey	Europe & Asia	12,800,000	2.80%
21	Tehran	Iran	Asia	12,800,000	2.60%
23	Rio de Janeiro	Brazil	South America	12,600,000	1.00%
24	London	United Kingdom	Europe	12,400,000	0.70%
25	Lagos	Nigeria	Africa	11,800,000	3.20%

Source: Th. Brinkhoff: The Principal Agglomerations of the World, 2010-01-23

Another list defines megacities as urban agglomerations instead of metropolitan areas.^[22] As of 2007, there are 22 megacities by this definition.

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:

• Boston–New York City–Philadelphia–Baltimore–Washington (Northeast megalopolis) (55,000,000)
• Liverpool-Manchester-Birmingham-London-Brussels-Antwerp-Amsterdam-Rotterdam-The Hague-Cologne-Rhine-Ruhr-Frankfurt am Main-Munich-Stuttgart-Basel-Zurich-Turin-Milan (Blue Banana) Megalopolis, European backbone (78.000.000)
• Los Angeles–San Diego-Tijuana (Southern California and San Diego-Tijuana metropolitan area)
• Quebec City-Montreal-Ottawa-Toronto-Hamilton-Windsor (Quebec City-Windsor Corridor) (17,900,000)
• Madison-Rockford-South Bend-Chicago-Milwaukee (Chicago metropolitan area)
• Mexico City-Toluca-Puebla-Pachuca-Tlaxcala-Santiago de Querétaro (Valley of Mexico)
• Vancouver-Seattle-Portland (Cascadia)
• Tokyo–Nagoya–Osaka-Kobe-Kyoto (Taiheiyō Belt) (82,900,000)
• Jakarta-Bogor-Depok-Tangerang-Bekasi-Cianjur - The first five commonly referred to as the Jabodetabek area.
• Tehran-Karaj-Qazvin-Shahriyar-Varamin
• San Francisco-Oakland-San Jose-Sacramento (San Francisco Bay Area) (7,700,000)
• Rio–São Paulo–Belo Horizonte-Campinas^[23]
• Dallas (I-35 Corridor)
• Johannesburg-Pretoria-Vaal Triangle (Gauteng Global City Region)

Emerging megacities in China (in decreasing order of population):

• Yangtze River Delta (Shanghai-Hangzhou-Nanjing-Ningbo-Suzhou) (87,430,000)
• Pearl River Delta (Hong Kong-Shenzhen-Zhuhai-Macau) (50,000,000)^[24]
• Chongqing (31,442,300)
• Beijing-Tianjin corridor (27,350,000)

Emerging megacities in India (in decreasing order of population):

• Mumbai-Ahmedabad-Surat-Pune-Vadodara-Nasik-Navsari corridor (49,000,000)
• Lucknow-Kanpur corridor (10,000,000)
• Hyderabad-Secunderabad (10,000,000)

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.

Regional uses of the term Megacity

Canada

In 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.

Nova Scotia

• Halifax - the cities of Halifax and Dartmouth and surrounding municipalities were merged in 1996 into the Halifax Regional Municipality, often called a "megacity," with a total population under 400,000.

Ontario

• Toronto - In 1998 the municipalities that constituted the Municipality of Metropolitan Toronto were merged into a new City of Toronto, currently the largest of the Canadian cities, with a population of 2,503,281 in 2006.
• Kawartha Lakes - primarily rural Victoria County had its townships, towns and villages merged into a "megacity" in 2000. The area has a population of only 70,000 (several thousand less than nearby city of Peterborough) yet takes up an area of 3,059.22 km² giving it a density of only a mere 22.6 persons per km².
• Ottawa - the municipalities that constituted the Regional Municipality of Ottawa-Carleton were merged into a new City of Ottawa in 2001.
• Greater Sudbury - resulted from the merger of the former Regional Municipality of Sudbury in 2001.
• Hamilton - the municipalities that constituted Hamilton-Wentworth merged in a new City of Hamilton in 2001.

Quebec

• Gatineau - five municipalities in southwestern Quebec (Gatineau, Hull, Aylmer, Buckingham, and Masson-Angers) were merged into a new City of Gatineau in 2002.
• Montreal - on January 1, 2002, all of the municipalities on the island of Montreal were merged into a new City of Montreal for a short period of time until January 1, 2006, when a partial demerger occurred.
• Saguenay - The cities of Chicoutimi, Jonquière, La Baie and Laterrière, along with the municipalities of Lac-Kénogami and Shipshaw and part of the township of Tremblay, were amalgamated into the City of Saguenay in 2002.

In fiction

• Fictional megacities feature in much dystopian science fiction, with examples such as the Sprawl, featured in William Gibson's Neuromancer, and Mega-City One, a megalopolis of over 400 million people across the east coast of the United States, features in the Judge Dredd comic, serialized in 2000 AD. Demolition Man (1993) features a megacity called "San Angeles", formed from the joining of Los Angeles, Santa Barbara, San Diego, and the surrounding metropolitan regions following a massive earthquake in 2010.
• The 1973 film Soylent Green, based on Harry Harrison's novel Make Room, Make Room, depicted New York City in 2022 with a population of 40 million. The city has a huge food shortage, which leads one company, the manufacturers of the popular food "Soylent Green" to create food out of the deceased, telling customers that it is plankton. It is not said how large the city is, but the main character does make the comment that a wanted criminal is "over the city line in Philadelphia" making the viewer wonder if the city has sprawled that far.
• Planet-wide megacities (ecumenopoleis) have been depicted, including Trantor in Isaac Asimov's Foundation series of books, Coruscant in the Star Wars universe, 'City Europe' in David Wingrove's Chung Kuo series of books, Holy Terra and the hive cities of Necromunda in Warhammer 40,000, and Ravnica in the eponymous Magic: The Gathering expansion. In Stargate Atlantis, the Asurans appear to have an extremely large city that may or may not be an ecumenopolis, named Asuras.
• Many of these fictional depictions were inspired by Fritz Lang's 1927 film, Metropolis. Ridley Scott's 1982 film, Blade Runner, features an influential depiction of Los Angeles in 2019. The MMORPG game "Guild Wars" has a massive, fictional megacity on its southern continent, Cantha, called Kaineng City which is very run down, corrupted, and in colossal slums and poverty. The city is a daily struggle for survival infested with crime, plagues, starvation, and a massive sewer system called the "undercity".
• Another MMORPG game City of Heroes is set in the fictional megacity known as Paragon City, which contains two other cities: Galaxy City and Skyway City. In the two novels based on the game as well as the official timeline for the game, Paragon City has existed at least as far back as the early to mid-1800s. Paragon is depicted as being one of if not the single largest city on Earth in its world setting.
• The sprawling metropolis featured in The Matrix series of films can be considered a megacity. While the city is never referenced by name in the films, in the MMORPG The Matrix Online, the city itself is simply called the Mega City. The city is based on Sydney, Chicago, and Oakland, California.
• The Fifth Element has a parody of New York City set in 2263 which is completely built up with depleted water levels the city is transformed into a much bigger metropolis than it is today. Buildings are so high that people use flying cars to get around and the ground level of the Earth is obscured by cloud cover.

See also

• Amalgamation (politics)
• Arcology
• Consolidated city-county
• Ekistics
• Principles of Intelligent Urbanism
• Urban sprawl
• World largest cities
• List of largest cities throughout history
• List of metropolitan areas by population

Notes

References

External links

• United Nations Department of Economic and Social Affairs, Population Division
• Lagos la Vida Loca by Mariana van Zeller on Current TV Nov. 2007
• Megacities Task Force
• Maps of US Megacities from radicalcartography.net
• IEEE Spectrum report on "Engineering the Megacity"
• URBAN PLANET: Collective Identities, Governance and Empowerment in Megacities