Megacity

Tokyo is the World's largest megacity

Seoul, South Korea is the World's second largest megacity. This is the Gangnam-gu district of Seoul.

Greater Mexico City is the largest city in the Americas and the world's third 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). 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.

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] 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 Chang'an,Kaifeng also experienced huge population booms during prosperous empires. According to the census in the year 742 recorded in the New Book of Tang, 362,921 families with 1,960,188 persons were counted in Jingzhao Fu (京兆府), the metropolitan area including small cities in the vicinity.^[16]

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.^[17]

In 1950, New York City was the only urban area with a population of over 10 million.^[18] Geographers had identified 25 such areas as of October 2005,^[19] 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.^[20][21] 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	Guangzhou	China	Asia	24,200,000	4.00%
3	Seoul	South Korea	Asia	24,200,000	1.40%
4	Mexico City	Mexico	North America	23,400,000	2.00%
5	Delhi	India	Asia	23,200,000	4.60%
6	Mumbai	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 [22]	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%
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.^[23] As of 2007, there are 22 megacities by this definition.

Challenges

Smog in Cairo, Egypt. Cairo is the fifteenth most populous city in the world.

Slums

According to the United Nations, the proportion of urban dwellers living in slums decreased from 47 percent to 37 percent in the developing world between 1990 and 2005.^[24] However, due to rising population, the number of slum dwellers is rising. 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. Slum dwellers often have minimal or no access to education, healthcare, or the urban economy.

Homelessness

Megacities often have significant numbers of homeless people. The actual legal definition of homelessness varies from country to country, or among different entities or institutions in the same country or region.^[25]

Traffic congestion

Traffic congestion is a condition on road networks that occurs as use increases, and is characterized by slower speeds, longer trip times, and increased vehicular queueing.

Urban sprawl

A flat land area in the greater Los Angeles area almost completely filled with houses, buildings, roads, and freeways. Areas constructed to capacity contribute to urban expansion.

Urban sprawl, also known as suburban sprawl, is a multifaceted concept, which includes the spreading outwards of a city and its suburbs to its outskirts to low-density, auto-dependent development on rural land, with associated design features that encourage car dependency.^[26] As a result, some critics argue that sprawl has certain disadvantages, including, longer transport distances to work, high car dependence, inadequate facilities e.g.: health, cultural. etc. and higher per-person infrastructure costs. Discussions and debates about sprawl are often obfuscated by the ambiguity associated with the phrase. For example, some commentators measure sprawl only with the average number of residential units per acre in a given area. But others associate it with decentralization (spread of population without a well-defined center), discontinuity (leapfrog development, as defined below), segregation of uses, etc.

Gentrification

Gentrification and urban gentrification denote the socio-cultural changes in an area resulting from wealthier people buying housing property in a less prosperous community.^[27] Consequent to gentrification, the average income increases and average family size decreases in the community, which may result in the informal economic eviction of the lower-income residents, because of increased rents, house prices, and property taxes. This type of population change reduces industrial land use when it is redeveloped for commerce and housing. In addition, new businesses, catering to a more affluent base of consumers, tend to move into formerly blighted areas, further increasing the appeal to more affluent migrants and decreasing the accessibility to less wealthy natives.

Environmental problems

Air pollution

Air pollution is the introduction of chemicals, particulate matter, or biological materials that cause harm or discomfort to humans or other living organisms, or damages the natural environment into the atmosphere. Many urban areas have significant problems with smog, a type of air pollution derived from vehicular emission from internal combustion engines and industrial fumes that react in the atmosphere with sunlight to form secondary pollutants that also combine with the primary emissions to form photochemical smog.

Smog is also caused by large amounts of coal burning, which creates a mixture of smoke and sulfur dioxide. World coal consumption was about 6,743,786,000 short tons in 2006^[28] and is expected to increase 48% to 9.98 billion short tons by 2030.^[29] China produced 2.38 billion tons in 2006. India produced about 447.3 million tons in 2006. 68.7% of China's electricity comes from coal. The USA consumes about 14% of the world total, using 90% of it for generation of electricity.^[30]

Regional uses of the term

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

• Many of the following fictional cities were inspired by Fritz Lang's 1927 film, Metropolis and the influential depiction of Los Angeles in Ridley Scott's 1982 film, Blade Runner.
• Megacities are a common backdrop in dystopian science fiction, with examples such as the Sprawl in William Gibson's Neuromancer^[31], and Mega-City One, a megalopolis of over 400 million people across the east coast of the United States, in the Judge Dredd comic.^[32] In Demolition Man a megacity called "San Angeles" was formed from the joining of Los Angeles, Santa Barbara, San Diego and the surrounding metropolitan regions following a massive earthquake in 2010.^[33]
• Fictional planet-wide megacities (ecumenopoleis) include Trantor in Isaac Asimov's Foundation series of books and Coruscant in the Star Wars universe.^[34] Other examples are '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.
• The Fifth Element features a parody of New York City set in 2263. Buildings are so high that people use flying cars to get around and the ground level of the Earth is obscured by cloud cover.
• 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. 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" implying that it has sprawled that far.
• 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-19th century.
• The sprawling metropolis featured in The Matrix series of films can be considered a megacity. It is based on Sydney, Chicago and Oakland, California. While the city is never referenced by name in the films, in the MMORPG The Matrix Online, the city itself is called the Mega City.

See also

Notes

References

External links

• United Nations Department of Economic and Social Affairs, Population Division
• e-Geopolis project Research Group, University Paris-Diderot
• 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