The expanding Los Angeles metropolitan area is an early example of suburbanization.1

Urbanization urbanisation or urban drift is the physical growth of urban areas as a result of global change. Urbanization is also defined by the United Nations as movement of people from rural to urban areas with population growth equating to urban migration. The United Nations projected that half of the world's population would live in urban areas at the end of 2008.2

Urbanization is closely linked to modernization industrialization and the sociological process of rationalization. Urbanization can describe a specific condition at a set time i.e. the proportion of total population or area in cities or towns or the term can describe the increase of this proportion over time. So the term urbanization can represent the level of urban relative to overall population or it can represent the rate at which the urban proportion is increasing. Contents 1 Movement 2 Causes 3 Economic effects 4 Environmental effects 5 Changing forms 6 See also 7 References 8 External links Movement Percentage of population which is urbanized by country as of 2006.3

As more and more people leave villages and farms to live in cities urban growth results. The rapid growth of cities like Chicago in the late 19th century and Mumbai a century later can be attributed largely to rural-urban migration. This kind of growth is especially commonplace in developing countries.

The rapid urbanization of the worlds population over the twentieth century is described in the 2005 Revision of the UN World Urbanization Prospects report. The global proportion of urban population rose dramatically from 13% (220 million) in 1900 to 29% (732 million) in 1950 to 49% (3.2 billion) in 2005. The same report projected that the figure is likely to rise to 60% (4.9 billion) by 2030.4 However French economist Philippe Bocquier writing in THE FUTURIST magazine has calculated that "the proportion of the world population living in cities and towns in the year 2030 would be roughly 50% substantially less than the 60% forecast by the United Nations (UN) because the messiness of rapid urbanization is unsustainable. Both Bocquier and the UN see more people flocking to cities but Bocquier sees many of them likely to leave upon discovering that theres no work for them and no place to live."5 Percentage of World Population: Urban vs. Rural.6

According to the UN State of the World Population 2007 report sometime in the middle of 2007 the majority of people worldwide will be living in towns or cities for the first time in history; this is referred to as the arrival of the "Urban Millennium" or the 'tipping point'. In regard to future trends it is estimated 93% of urban growth will occur in developing nations with 80% of urban growth occurring in Asia and Africa.78

Urbanization rates vary between countries. The United States and United Kingdom have a far higher urbanization level than China India Swaziland or Niger but a far slower annual urbanization rate since much less of the population is living in a rural area. Urbanization in the United States never reached the Rocky Mountains in locations such as Jackson Hole Wyoming; Telluride Colorado; Taos New Mexico; Douglas County Colorado and Aspen Colorado. The state of Vermont has also been affected as has the coast of Florida the Birmingham-Jefferson County AL area the Pacific Northwest and the barrier islands of North Carolina. In the United Kingdom two major examples of new urbanization can be seen in Swindon Wiltshire and Milton Keynes Buckinghamshire.9 These two towns show some of the quickest growth rates in Europe. Center of So Paulo one of the largest metropolises in the world. Causes Population age comparison between rural Pocahontas County Iowa and urban Johnson County Iowa illustrating the flight of young adults (red) to urban centers in Iowa.10 The City of Chicago Illinois is an example of the early American grid system of development. The grid is enforced even on uneven topography. Example of rapid and expansive urban development in Manila as opposed to the slums hidden in shockingly close proximity. Urbanization is not always attributed to high density. In Manila the cost of living has forced residents to live in low quality slums and shanty towns

Urbanization occurs naturally from individual and corporate efforts to reduce time and expense in commuting and transportation while improving opportunities for jobs education housing and transportation. Living in cities permits individuals and families to take advantage of the opportunities of proximity diversity and marketplace competition.

People move into cities to seek economic opportunities. A major contributing factor is known as "rural flight". In rural areas often on small family farms it is difficult to improve one's standard of living beyond basic sustenance. Farm living is dependent on unpredictable environmental conditions and in times of drought flood or pestilence survival becomes extremely problematic. In modern times industrialization of agriculture has negatively affected the economy of small and middle-sized farms and strongly reduced the size of the rural labour market.

Cities in contrast are known to be places where money services and wealth are centralized. Cities are where fortunes are made and where social mobility is possible. Businesses which generate jobs and capital are usually located in urban areas. Whether the source is trade or tourism it is also through the cities that foreign money flows into a country. It is easy to see why someone living on a farm might wish to take their chance moving to the city and trying to make enough money to send back home to their struggling family. There are better basic services as well as other specialist services that aren't found in rural areas. There are more job opportunities and a greater variety of jobs. Health is another major factor. People especially the elderly are often forced to move to cities where there are doctors and hospitals that can cater for their health needs. Other factors include a greater variety of entertainment (restaurants movie theaters theme parks etc.) and a better quality of education namely universities. Due to their high populations urban areas can also have much more diverse social communities allowing others to find people like them when they might not be able to in rural areas. These conditions are heightened during times of change from a pre-industrial society to an industrial one. It is at this time that many new commercial enterprises are made possible thus creating new jobs in cities. It is also a result of industrialization that farms become more mechanized putting many labourers out of work. This is currently occurring fastest in India.citation needed Economic effects One of the last houses of the old Russian village of Lukeryino most of which has been demolished over the last 30 years to make way for 9-story apartment buildings in the growing city of Kstovo such as the one in the background In recent yearswhen urbanization of rural areas has increased. As agriculture more traditional local services and small-scale industry give way to modern industry the urban and related commerce with the city drawing on the resources of an ever-widening area for its own sustenance and goods to be traded or processed into manufactures. Research in urban ecology finds that larger cities provide more specialized goods and services to the local market and surrounding areas function as a transportation and wholesale hub for smaller places and accumulate more capital financial service provision and an educated labor force as well as often concentrating administrative functions for the area in which they lie. This relation among places of different sizes is called the urban hierarchy. As cities develop effects can include a dramatic increase in costs often pricing the local working class out of the market including such functionaries as employees of the local municipalities. For example Eric Hobsbawm's book The age of the revolution: 17891848 (published 1962 and 2005) chapter 11 stated "Urban development in our period 17891848 was a gigantic process of class segregation which pushed the new labouring poor into great morasses of misery outside the centres of government and business and the newly specialised residential areas of the bourgeoisie. The almost universal European division into a 'good' west end and a 'poor' east end of large cities developed in this period." This is likely due the prevailing south-west wind which carries coal smoke and other airborne pollutants downwind making the western edges of towns preferable to the eastern ones. Similar problems now affect the developing world rising inequality resulting from rapid urbanisation trends. The drive for rapid urban growth and often efficiency can lead to less equitable urban development think tanks such as the Overseas Development Institute have even proposed policies that encourage labour intensive growth as a means of absorbing the influx of low skilled and unskilled labour.11 Urbanization is often viewed as a negative trend but can in fact be perceived simply as a natural occurrence from individual and corporate efforts to reduce expense in commuting and transportation while improving opportunities for jobs education housing and transportation. Living in cities permits individuals and families to take advantage of the opportunities of proximity diversity and marketplace competition.12131415 Environmental effects The urban heat island has become a growing concern and is increasing over the years. The urban heat island is formed when industrial and urban areas are developed and heat becomes more abundant. In rural areas a large part of the incoming solar energy is used to evaporate water from vegetation and soil. In cities where less vegetation and exposed soil exists the majority of the suns energy is absorbed by urban structures and asphalt. Hence during warm daylight hours less evaporative cooling in cities allows surface temperatures to rise higher than in rural areas. Additional city heat is given off by vehicles and factories as well as by industrial and domestic heating and cooling units.16 This effect causes the city to become 2 to 10o F (1 to 6o C) warmer than surrounding landscapes.17 Impacts also include reducing soil moisture and intensification of carbon dioxide emissions.18 In his book Whole Earth Discipline Stewart Brand argues that the effects of urbanization are on the overall positive for the environment. Firstly the birth rate of new urban dwellers falls immediately to replacement rate and keeps falling. This can prevent overpopulation in the future. Secondly it puts a stop to destructive subsistence farming techniques like slash and burn agriculture. Finally it minimizes land use by humans leaving more for nature.13 Changing forms Massive urbanization in Delhi India resulted in tremendous strain on the city's infrastructure. Karachi Pakistan is an example of an urban agglomeration that has experienced rapid urbanisation as a result of economic migration. The planned Dwarka Sub City can be seen in foreground while the unplanned and congested residential areas of West Delhi are visible in the background. Different forms of urbanization can be classified depending on the style of architecture and planning methods as well as historic growth of areas. In cities of the developed world urbanization traditionally exhibited a concentration of human activities and settlements around the downtown area the so-called in-migration. In-migration refers to migration from former colonies and similar places. The fact that many immigrants settle in impoverished city centres led to the notion of the "peripheralization of the core" which simply describes that people who used to be at the periphery of the former empires now live right in the centre. Recent developments such as inner-city redevelopment schemes mean that new arrivals in cities no longer necessarily settle in the centre. In some developed regions the reverse effect originally called counter urbanisation has occurred with cities losing population to rural areas and is particularly common for richer families. This has been possible because of improved communications and has been caused by factors such as the fear of crime and poor urban environments. Later termed "white flight" the effect is not restricted to cities with a high ethnic minority population. When the residential area shifts outward this is called suburbanization. A number of researchers and writers suggest that suburbanization has gone so far to form new points of concentration outside the downtown both in developed and developing countries such as India.19 This networked poly-centric form of concentration is considered by some an emerging pattern of urbanization. It is called variously exurbia edge city (Garreau 1991) network city (Batten 1995) or postmodern city (Dear 2000). Los Angeles is the best-known example of this type of urbanization. Rural migrants are attracted by the possibilities that cities can offer but often settle in shanty towns and experience extreme poverty. In the 1980s this was attempted to be tackled with the urban bias theory which was promoted by Michael Lipton who wrote: "...the most important class conflict in the poor countries of the world today is not between labour and capital. Nor is it between foreign and national interests. It is between rural classes and urban classes. The rural sector contains most of the poverty and most of the low-cost sources of potential advance; but the urban sector contains most of the articulateness organization and power. So the urban classes have been able to win most of the rounds of the struggle with the countryside...".20 Most of the urban poor in developing countries able to find work can spend their lives in insecure poorly paid jobs. According to research by the Overseas Development Institute pro-poor urbanisation will require labour intensive growth supported by labour protection flexible land use regulation and investments in basic services.' 21 Urbanization can be planned urbanization or organic. Planned urbanization i.e.: planned community or the garden city movement is based on an advance plan which can be prepared for military aesthetic economic or urban design reasons. Examples can be seen in many ancient cities; although with exploration came the collision of nations which meant that many invaded cities took on the desired planned characteristics of their occupiers. Many ancient organic cities experienced redevelopment for military and economic purposes new roads carved through the cities and new parcels of land were cordoned off serving various planned purposes giving cities distinctive geometric designs. UN agencies prefer to see urban infrastructure installed before urbanization occurs. Landscape planners are responsible for landscape infrastructure (public parks sustainable urban drainage systems greenways etc.) which can be planned before urbanization takes place or afterward to revitalize an area and create greater livability within a region. Concepts of control of the urban expansion are considered in the American Institute of Planners.22 See also Counter urbanization Division of labour People Flow Pseudo-urbanization Suburban colonization Suburban sprawl Urban morphology Contributors to urbanization: British Agricultural Revolution Industrial Revolution Industrialisation Neolithic Revolution Rural flight Regional: Urbanization by country Urbanization in Africa Urbanization in China References Bonnie Richardson reviews Drosscape: Wasting Land in Urban America by Alan Berger (2008). "Can Designers Solve the Problem of Urban Wasteland". Terrain. http://www.terrain.org/reviews/20/drosscape.htm.  The Associated Press (February 26 2008). "UN says half the world's population will live in urban areas by end of 2008". International Herald Tribune. http://www.iht.com/articles/ap/2008/02/26/news/UN-GEN-UN-Growing-Cities.php.  "Statistical Tables". http://www.unicef.org/sowc08/docs/sowc08tableStatisticalTables.pdf. Retrieved 15 October 2010.  "World Urbanization Prospects: The 2005 Revision Pop. Division Department of Economic and Social Affairs UN". http://www.un.org/esa/population/publications/WUP2005/2005wup.htm.  "Britannica Futurist Blog". http://www.britannica.com/blogs/2008/12/forecast-8-urbanization-to-hit-60-by-2030/.  "United Nations Department of Economic and Social Affairs". http://esa.un.org/unup/.  "UN State of the World Population". UNFPA. 2007. http://web.unfpa.org/swp/2007/english/chapter1/urbanization.html.  Ankerl Guy (1986). Urbanization Overspeed in Tropical Africa. INUPRESS Geneva. ISBN 2881550002.  Milton Keynes intelligence Observatory (10/03/2008). "Population Bulletin 2007/2008". Press release. http://www.mkiobservatory.org.uk/page.aspxid1914&siteID1026. Retrieved 11/06/2008.  based on 2000 U.S. Census Data Grant Ursula (2008) Opportunity and exploitation in urban labour markets London: Overseas Development Institute Glaeser Edward (Spring 1998). "Are Cities Dying". The Journal of Economic Perspectives 12 (2): 139160.  a b Brand Stewart. "Whole Earth Discipline - annotated extract". http://web.me.com/stewartbrand/DISCIPLINEfootnotes/2-CityPlanet.html. Retrieved 2009-11-29.  Nowak Jeremy. "Neighborhood Iniative and the Regional Economy" Economic Development Quarterly Vol. 11 No. 1 February 1997 pp. 3-10. "Using the Gall-Peters Projection it is estimated that come 2015 the worlds urban population is set to exceed 4 billion most of this growth is expected in Africa and Asia and China to be 50% urbanised" Park H.-S. (1987). Variations in the urban heat island intensity affected by geographical environments. Environmental Research Center papers no. 11. Ibaraki Japan: Environmental Research Center The University of Tsukuba. "Heat Island Effect" "Heating Up: Study Shows Rapid Urbanization in China Warming the Regional Climate Faster than Other Urban Areas". http://gtresearchnews.gatech.edu/newsrelease/china-climate.htm.  Sridhar K. (37 (3) 2007 314:344). "Density gradients and their determinants: Evidence from India". Regional Science and Urban Economics. http://www.sciencedirect.com/scienceobArticleURL&udiB6V89-4MW901N-1&user10&rdoc1&fmt&origsearch&sortd&docanchor&viewc&searchStrId1120294191&rerunOrigingoogle&acctC000050221&version1&urlVersion0&userid10&md5bbf269efb8ad7f431443d95d90adeadf. dead link Varshney A. (ed.) 1993. "Beyond Urban Bias" p.5. London: Frank Cass. "Opportunity and exploitation in urban labour markets". Overseas Development Institute. November 2008. http://www.odi.org.uk/resources/odi-publications/briefing-papers/44-urban-labour-markets-exploitation.pdf.  Lovelace E.H. (1965). "Control of urban expansion: the Lincoln Nebraska experience". Journal of the American Institute of Planners 31:4: 348352.  Allen J Scott (1988) "Metropolis: From the Division of Labor to Urban Form" University of California Press. External links United Nations World Urbanization Prospects the 2009 Revision Web Site of the United Nations Population Division Geopolis: research groupuniversity of Paris-Diderot France Tomorrow's Crises Today - the humanitarian dimension of urbanization by IRIN The Natural History of Urbanization by Lewis Mumford The World System urbanization dynamics by Andrey Korotayev Brief review of world socio-demographic trends includes review of global urbanization trends