Urbanization (or urbanisation) refers to the population shift from
rural to
urban areas, the corresponding decrease in the proportion of people living in rural areas, and the ways in which societies adapt to this change. It is predominantly the process by which
towns and
cities are formed and become larger as more people begin living and working in central areas.
Although the two concepts are sometimes used interchangeably, urbanization should be distinguished from
urban growth. Urbanization refers to the ''proportion'' of the total national population living in areas classified as urban, whereas urban growth strictly refers to the ''absolute'' number of people living in those areas. It is predicted that by 2050 about 64% of the
developing world
A developing country is a sovereign state with a lesser developed industrial base and a lower Human Development Index (HDI) relative to other countries. However, this definition is not universally agreed upon. There is also no clear agreem ...
and 86% of the
developed world will be urbanized. That is equivalent to approximately 3 billion urbanites by 2050, much of which will occur in Africa and
Asia.
Notably, the United Nations has also recently projected that nearly all global population growth from 2017 to 2030 will be by cities, with about 1.1 billion new urbanites over the next 10 years.
Urbanization is relevant to a range of disciplines, including
urban planning,
geography,
sociology,
architecture,
economics,
education,
statistics
Statistics (from German language, German: ''wikt:Statistik#German, Statistik'', "description of a State (polity), state, a country") is the discipline that concerns the collection, organization, analysis, interpretation, and presentation of ...
and
public health. The phenomenon has been closely linked to
modernization
Modernization theory is used to explain the process of modernization within societies. The "classical" theories of modernization of the 1950s and 1960s drew on sociological analyses of Karl Marx, Emile Durkheim and a partial reading of Max Weber, ...
,
industrialization
Industrialisation ( alternatively spelled industrialization) is the period of social and economic change that transforms a human group from an agrarian society into an industrial society. This involves an extensive re-organisation of an econo ...
, and the
sociological process of
rationalization. Urbanization can be seen as a specific condition at a set time (e.g. the proportion of total population or area in cities or towns), or as an increase in that condition over time. Therefore, urbanization can be quantified either in terms of the level of urban development relative to the overall population, or as the
rate
Rate or rates may refer to:
Finance
* Rates (tax), a type of taxation system in the United Kingdom used to fund local government
* Exchange rate, rate at which one currency will be exchanged for another
Mathematics and science
* Rate (mathema ...
at which the urban proportion of the population is increasing. Urbanization creates enormous social, economic and environmental changes, which provide an opportunity for
sustainability
Specific definitions of sustainability are difficult to agree on and have varied in the literature and over time. The concept of sustainability can be used to guide decisions at the global, national, and individual levels (e.g. sustainable livi ...
with the "potential to use resources more efficiently, to create more sustainable land use and to protect the biodiversity of natural ecosystems."
Developing
urban resilience and
urban sustainability in the face of increased urbanization is at the center of international policy in
Sustainable Development Goal 11
Sustainable Development Goal 11 (SDG 11 or Global Goal 11), titled " sustainable cities and communities", is one of 17 Sustainable Development Goals established by the United Nations General Assembly in 2015. The official mission of SDG 11 is ...
"Sustainable cities and communities."
Urbanization is not merely a modern phenomenon, but a rapid and historic transformation of human
social roots on a global scale, whereby predominantly
rural culture is being rapidly replaced by predominantly
urban culture. The first major change in settlement patterns was the accumulation of
hunter-gatherers into villages many thousands of years ago. Village culture is characterized by common bloodlines, intimate relationships, and communal behaviour, whereas urban culture is characterized by distant bloodlines, unfamiliar relations, and competitive behaviour. This unprecedented movement of people is forecast to continue and intensify during the next few decades, mushrooming cities to sizes unthinkable only a century ago. As a result, the world urban population growth curve has up till recently followed a quadratic-hyperbolic pattern.
History
From the development of the earliest cities in
Indus valley civilization
The Indus Valley Civilisation (IVC), also known as the Indus Civilisation was a Bronze Age civilisation in the northwestern regions of South Asia, lasting from 3300 BCE to 1300 BCE, and in its mature form 2600 BCE to 1900&n ...
,
Mesopotamia and
Egypt until the 18th century, an equilibrium existed between the vast majority of the population who were engaged in
subsistence agriculture
Subsistence agriculture occurs when farmers grow food crops to meet the needs of themselves and their families on smallholdings. Subsistence agriculturalists target farm output for survival and for mostly local requirements, with little or no su ...
in a rural context, and small centres of populations in the towns where economic activity consisted primarily of trade at
markets and manufactures on a small scale. Due to the primitive and relatively stagnant state of agriculture throughout this period, the ratio of rural to urban population remained at a fixed equilibrium. However, a significant increase in the percentage of the global urban population can be traced in the 1st millennium BCE.
With the onset of the
British agricultural and
industrial revolution in the late 18th century, this relationship was finally broken and an unprecedented growth in urban population took place over the course of the 19th century, both through continued migration from the countryside and due to the tremendous
demographic expansion that occurred at that time. In
England and
Wales, the proportion of the population living in cities with more than 20,000 people jumped from 17% in 1801 to 54% in 1891. Moreover, and adopting a broader definition of urbanization, while the urbanized population in England and Wales represented 72% of the total in 1891, for other countries the figure was 37% in
France, 41% in
Prussia and 28% in the
United States.
As labourers were freed up from working the land due to higher
agricultural productivity they converged on the new
industrial cities like
Manchester and
Birmingham which were experiencing a boom in commerce, trade, and industry. Growing trade around the world also allowed cereals to be imported from
North America
North America is a continent in the Northern Hemisphere and almost entirely within the Western Hemisphere. It is bordered to the north by the Arctic Ocean, to the east by the Atlantic Ocean, to the southeast by South America and the Car ...
and
refrigerated meat from
Australasia and
South America. Spatially,
cities also expanded due to the development of
public transport systems, which facilitated commutes of longer distances to the
city centre
A city centre is the commercial, cultural and often the historical, political, and geographic heart of a city. The term "city centre" is primarily used in British English, and closely equivalent terms exist in other languages, such as "" in Fren ...
for the
working class.
Urbanization rapidly spread across the
Western world and, since the 1950s, it has begun to take hold in the
developing world
A developing country is a sovereign state with a lesser developed industrial base and a lower Human Development Index (HDI) relative to other countries. However, this definition is not universally agreed upon. There is also no clear agreem ...
as well. At the turn of the 20th century, just 15% of the world population lived in cities. According to the
UN, the year 2007 witnessed the turning point when more than 50% of the world population were living in cities, for the first time in
human history
Human history, also called world history, is the narrative of humanity's past. It is understood and studied through anthropology, archaeology, genetics, and linguistics. Since the invention of writing, human history has been studied throug ...
.
Yale University in June 2016 published urbanization data from the time period 3700 BC to 2000 AD, the data was used to make a
video showing the development of cities on the
world during the time period. The origins and spread of urban centers around the world were also mapped by archaeologists.
Causes
Urbanization occurs either organically or planned as a result of individual, collective and state action. Living in a city can be culturally and economically beneficial since it can provide greater opportunities for access to the labour market, better education, housing, and safety conditions, and reduce the time and expense of commuting and transportation. Conditions like density, proximity, diversity, and marketplace competition are elements of an urban environment that deemed beneficial. However, there are also harmful social phenomena that arise: alienation, stress, increased cost of living, and mass marginalization that are connected to an urban way of living.
Suburbanization, which is happening in the cities of the largest developing countries, may be regarded as an attempt to balance these harmful aspects of urban life while still allowing access to the large extent of shared resources.
In cities, money, services, wealth and opportunities are centralized. Many rural inhabitants come to the city to seek their fortune and alter their social position. Businesses, which provide jobs and exchange capital, are more concentrated in urban areas. Whether the source is trade or tourism, it is also through the ports or banking systems, commonly located in cities, that foreign money flows into a country.
Many people move into cities for economic opportunities, but this does not fully explain the very high recent urbanization rates in places like China and India.
Rural flight
Rural flight (or rural exodus) is the migratory pattern of peoples from rural areas into urban areas. It is urbanization seen from the rural perspective.
In industrializing economies like Britain in the eighteenth century or East Asia in the ...
is a contributing factor to urbanization. In rural areas, often on small family farms or collective farms in villages, it has historically been difficult to access manufactured goods, though the relative overall
quality of life is very subjective, and may certainly surpass that of the city. Farm living has always been susceptible to unpredictable environmental conditions, and in times of
drought,
flood or pestilence, survival may become extremely problematic.
In a New York Times article concerning the acute migration away from farming in Thailand, life as a farmer was described as "hot and exhausting". "Everyone says the farmer works the hardest but gets the least amount of money". In an effort to counter this impression, the Agriculture Department of Thailand is seeking to promote the impression that farming is "honorable and secure".
However, in Thailand, urbanization has also resulted in massive increases in problems such as obesity. Shifting from a rural environment to an urbanized community also caused a transition to a diet that was mainly carbohydrate-based to a diet higher in fat and sugar, consequently causing a rise in obesity. City life, especially in modern urban slums of the developing world, is certainly hardly immune to pestilence or climatic disturbances such as floods, yet continues to strongly attract migrants. Examples of this were the
2011 Thailand floods
Severe flooding occurred during the 2011 monsoon season in Thailand. The flooding began at the end of July triggered by the landfall of Tropical Storm Nock-ten. These floods soon spread through the provinces of northern, northeastern, and centr ...
and
2007 Jakarta flood
The 2007 Jakarta flood was a major flood in Jakarta, the capital of Indonesia and affected several other areas around the city, such as West Java and Banten. The flood, beginning on February 2, 2007 was a result of heavy rain, deforestation in are ...
. Urban areas are also far more prone to
violence,
drugs
A drug is any chemical substance that causes a change in an organism's physiology or psychology when consumed. Drugs are typically distinguished from food and substances that provide nutritional support. Consumption of drugs can be via inhalat ...
, and other urban social problems. In the United States,
industrialization
Industrialisation ( alternatively spelled industrialization) is the period of social and economic change that transforms a human group from an agrarian society into an industrial society. This involves an extensive re-organisation of an econo ...
of
agriculture has negatively affected the economy of small and middle-sized farms and strongly reduced the size of the rural labour market.
Particularly in the developing world, conflict over land rights due to the effects of
globalization has led to less politically powerful groups, such as farmers, losing or forfeiting their land, resulting in obligatory migration into cities. In China, where land acquisition measures are forceful, there has been far more extensive and rapid urbanization (54%) than in India (36%), where peasants form militant groups (e.g.
Naxalites) to oppose such efforts. Obligatory and unplanned migration often results in the rapid growth of slums.
This is also similar to areas of violent conflict, where people are driven off their land due to violence.
Cities offer a larger variety of services, including specialist services not found in rural areas. These services require workers, resulting in more numerous and varied job opportunities. Elderly people may be forced to move to cities where there are doctors and hospitals that can cater to their health needs. Varied and high-quality educational opportunities are another factor in urban migration, as well as the opportunity to join, develop, and seek out social communities.
Urbanization also creates opportunities for women that are not available in rural areas. This creates a gender-related transformation where women are engaged in paid employment and have access to education. This may cause fertility to decline. However, women are sometimes still at a disadvantage due to their unequal position in the labour market, their inability to secure assets independently from male relatives and exposure to violence.
People in cities are more productive than in rural areas. An important question is whether this is due to
agglomeration effects or whether cities simply attract those who are more productive. Urban geographers have shown that there exists a large productivity gain due to locating in dense agglomerations. It is thus possible that agents locate in cities in order to benefit from these agglomeration effects.
Dominant conurbation
The dominant
conurbation
A conurbation is a region comprising a number of metropolises, cities, large towns, and other urban areas which through population growth and physical expansion, have merged to form one continuous urban or industrially developed area. In most ca ...
(s) of a country can benefit to a greater extent from the same things cities offer, making them magnets for not just the non-urban population, but also urban and suburban population from other cities. Dominant conurbations are quite often
primate cities, but do not have to be. For instance
Greater Manila is rather a conurbation than a city: its 20 million overall population (over 20% national population) make it very much a primate city, but Quezon City (2.7 million), the largest municipality in Greater Manila, and Manila (1.6 million), the capital, are not. A conurbation's dominance can be measured by output, wealth, and especially population, each expressed as a percentage of an entire country. Greater Seoul is one conurbation with massive dominance over South Korea, it is home to 50% of the entire national population.
Though Greater Busan-Ulsan (15%, 8 million) and Greater Osaka (14%, 18 million) exhibit strong dominance in their respective countries, they are losing population to their even more dominant rivals, Seoul and Tokyo respectively.
Economic effects
As cities develop, effects can include a dramatic increase and change 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
Eric John Ernest Hobsbawm (; 9 June 1917 – 1 October 2012) was a British historian of the rise of industrial capitalism, socialism and nationalism. A life-long Marxist, his socio-political convictions influenced the character of his work. H ...
's book ''The age of revolution: 1789–1848'' (published 1962 and 2005) chapter 11, stated "Urban development in our period was a gigantic process of class segregation, which pushed the new labouring poor into great morasses of misery outside the centres of government, business, and the newly specialized 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 to 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 urbanization 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 proposed policies that encourage labor-intensive growth as a means of absorbing the influx of low-skilled and unskilled labour. One problem these migrant workers are involved with is the growth of
slums. In many cases, the rural-urban low skilled or unskilled migrant workers, attracted by economic opportunities in urban areas, cannot find a job and afford housing in cities and have to dwell in slums.
Urban problems, along with infrastructure developments, are also fuelling suburbanization trends in developing nations, though the trend for core cities in said nations tends to continue to become ever denser. Urbanization is often viewed as a negative trend, but there are positives in the reduction of expenses 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 and diversity.
While cities have a greater variety of markets and goods than rural areas, infrastructure congestion, monopolization, high overhead costs, and the inconvenience of cross-town trips frequently combine to make marketplace competition harsher in cities than in rural areas.
In many developing countries where economies are growing, the growth is often erratic and based on a small number of industries. For young people in these countries, barriers exist such as lack of access to financial services and business advisory services, difficulty in obtaining credit to start a business, and lack of entrepreneurial skills, in order for them to access opportunities in these industries. Investment in human capital so that young people have access to quality education and infrastructure to enable access to educational facilities is imperative to overcoming economic barriers.
Environmental effects
Furthermore, urbanization improves environmental eminence through superior facilities and standards in urban areas as compared to rural areas. Lastly, urbanization curbs pollution emissions by increasing innovations. In his book ''
Whole Earth Discipline'', Stewart Brand argues that the effects of urbanization are primarily positive for the environment. First, the birth rate of new urban dwellers falls immediately to replacement rate and keeps falling, reducing environmental stresses caused by population growth. Secondly, emigration from rural areas reduces destructive subsistence farming techniques, such as improperly implemented
slash and burn agriculture.
Alex Steffen also speaks of the environmental benefits of increasing the urbanization level in "Carbon Zero: Imagining Cities that can save the planet", .
However, existing infrastructure and city planning practices are not sustainable. In July 2013 a report issued by the United Nations Department of Economic and Social Affairs warned that with 2.4 billion more people by 2050, the amount of food produced will have to increase by 70%, straining food resources, especially in countries already facing food insecurity due to changing environmental conditions. The mix of changing environmental conditions and the growing population of urban regions, according to UN experts, will strain basic sanitation systems and health care, and potentially cause a humanitarian and environmental disaster.
Urban heat island
The existence of
urban heat islands has become a growing concern over the years. An urban heat island is formed when industrial and urban areas produce and retain heat. Much of the solar energy that reaches rural areas is consumed by evaporation of water from vegetation and soil. In cities, where there are less vegetation and exposed soil, most of the sun's energy is instead absorbed by buildings and asphalt; leading to higher surface temperatures. Vehicles, factories, and industrial and domestic heating and cooling units release even more heat. As a result, cities are often 1 to 3 °C (1.8 to 5.4 °F) warmer than surrounding landscapes. Impacts also include reducing soil moisture and a reduction in reabsorption of carbon dioxide emissions.
Water quality
The occurrence of
eutrophication in bodies of water is another effect large urban populations have on the environment. When rain occurs in these large cities, the rain filters down the pollutants such as CO
2 and other greenhouse gases in the air onto the ground below. Then, those chemicals are washed directly into rivers, streams, and oceans, causing a decline in water quality and damaging marine ecosystems.
Eutrophication is a process which causes hypoxic water conditions and algal blooms that may be detrimental to the survival of aquatic life.
Harmful algal blooms, which produce dangerous toxins, thrive in eutrophic environments that are also rich in nitrogen and phosphorus. In these ideal conditions, they overtake surface water, making it difficult for other organisms to receive sunlight and nutrients. Overgrowth of algal blooms causes a decrease in overall water quality and disrupts the natural balance of aquatic ecosystems. Furthermore, as algal blooms die, CO
2 is produced, causing a more acidic environment, a process known as acidification.
The ocean's surface also has the ability to absorb CO
2 from the earth's atmosphere as emissions increase with the rise in urbanization. In fact, it is reported that the ocean absorbs a quarter of the CO
2 produced by humans.
This has been useful to the environment by decreasing the harmful effects of greenhouse gases, but also further perpetuates acidification. Changes in pH inhibit the proper formation of calcium carbonate, a crucial component for many marine organisms to maintain shells or skeletons.
This is especially true for many species of molluscs and coral. Regardless, some species have been able to instead adapt or thrive in a more acidic environment
Food waste
Rapid growth of communities create new challenges in the developed world and one such challenge is an increase in
food waste also known as urban food waste.
Food waste is the disposal of food products that can no longer be used due to unused products, expiration, or spoilage. The increase of food waste can raise environmental concerns such as increase production of
methane gases and attraction of
disease vectors
In epidemiology, a disease vector is any living agent that carries and transmits an infectious pathogen to another living organism; agents regarded as vectors are organisms, such as parasites or microbes. The first major discovery of a disease vec ...
.
Landfills are the third leading cause of the release of methane, causing a concern on its impact to our ozone and on the health of individuals. Accumulation of food waste causes increased fermentation, which increases the risk of rodent and bug migration. An increase in migration of disease vectors creates greater potential of disease spreading to humans.
Waste management systems vary on all scales from global to local and can also be influenced by lifestyle. Waste management was not a primary concern until after the Industrial Revolution. As urban areas continued to grow along with the human population, proper management of solid waste became an apparent concern. To address these concerns, local governments sought solutions with the lowest economic impacts which meant implementing technical solutions at the very last stage of the process.
Current waste management reflects these economically motivated solutions, such as incineration or unregulated landfills. Yet, a growing increase for addressing other areas of life cycle consumption has occurred from initial stage reduction to heat recovery and recycling of materials.
For example, concerns for mass consumption and
fast fashion
Fast fashion is a term used to describe the clothing industry's business model of replicating recent catwalk trends and High fashion, high-fashion designs, mass production, mass-producing them at a low cost, and bringing them to retail stores qui ...
have moved to the forefront of the urban consumers’ priorities. Aside from environmental concerns (e.g. climate change effects), other urban concerns for waste management are public health and land access.
Habitat fragmentation
Urbanization can have a large effect on biodiversity by causing a division of habitats and thereby alienation of species, a process known as
habitat fragmentation
Habitat fragmentation describes the emergence of discontinuities (fragmentation) in an organism's preferred environment (habitat), causing population fragmentation and ecosystem decay. Causes of habitat fragmentation include geological processes ...
. Habitat fragmentation does not destroy the habitat, as seen in
habitat loss, but rather breaks it apart with things like roads and railways This change may affect a species ability to sustain life by separating it from the environment in which it is able to easily access food, and find areas that they may hide from predation With proper planning and management, fragmentation can be avoided by adding corridors that aid in the connection of areas and allow for easier movement around urbanized regions.
Depending on the various factors, such as level of urbanization, both increases or decreases in "species richness" can be seen. This means that urbanization may be detrimental to one species but also help facilitate the growth of others. In instances of housing and building development, many times vegetation is completely removed immediately in order to make it easier and less expensive for construction to occur, thereby obliterating any native species in that area. Habitat fragmentation can filter species with limited dispersal capacity. For example, aquatic insects are found to have lower species richness in urban landscapes. The more urbanized the surrounding of habitat is, the fewer species can reach the habitat. Other times, such as with birds, urbanization may allow for an increase in richness when organisms are able to adapt to the new environment. This can be seen in species that may find food while scavenging developed areas or vegetation that has been added after urbanization has occurred i.e. planted trees in city areas
Health and social effects
In the developing world, urbanization does not translate into a significant increase in
life expectancy.
Rapid urbanization has led to increased mortality from
non-communicable diseases associated with lifestyle, including
cancer and
heart disease
Cardiovascular disease (CVD) is a class of diseases that involve the heart or blood vessels. CVD includes coronary artery diseases (CAD) such as angina and myocardial infarction (commonly known as a heart attack). Other CVDs include stroke, hea ...
.
Differences in mortality from
contagious diseases vary depending on the particular disease and location.
Urban health levels are on average better in comparison to rural areas. However, residents in poor urban areas such as slums and
informal settlements suffer "disproportionately from disease, injury, premature death, and the combination of ill-health and poverty entrenches disadvantage over time."
Many of the urban poor have difficulty accessing health services due to their inability to pay for them; so they resort to less qualified and unregulated providers.
While urbanization is associated with improvements in
public hygiene,
sanitation and access to
health care
Health care or healthcare is the improvement of health via the prevention, diagnosis, treatment, amelioration or cure of disease, illness, injury, and other physical and mental impairments in people. Health care is delivered by health profe ...
, it also entails changes in occupational,
dietary, and
exercise
Exercise is a body activity that enhances or maintains physical fitness and overall health and wellness.
It is performed for various reasons, to aid growth and improve strength, develop muscles and the cardiovascular system, hone athletic ...
patterns.
It can have mixed effects on health patterns, alleviating some problems, and accentuating others.
Nutrition
One such effect is the formation of
food desert
Food is any substance consumed by an organism for nutritional support. Food is usually of plant, animal, or fungal origin, and contains essential nutrients, such as carbohydrates, fats, proteins, vitamins, or minerals. The substance is ing ...
s. Nearly 23.5 million people in the United States lack access to supermarkets within one mile of their home. Several studies suggest that long distances to a grocery store are associated with higher rates of obesity and other health disparities.
Food deserts in developed countries often correspond to areas with a high-density of fast food chains and convenience stores that offer little to no fresh food. Urbanization has been shown to be associated with the consumption of less fresh fruits, vegetables, and whole grains and a higher consumption of processed foods and sugar-sweetened beverages.
Poor access to healthy food and high intakes of fat, sugar and salt are associated with a greater risk for obesity, diabetes and related chronic disease. Overall,
body mass index
Body mass index (BMI) is a value derived from the mass (weight) and height of a person. The BMI is defined as the body mass divided by the square of the body height, and is expressed in units of kg/m2, resulting from mass in kilograms and he ...
and
cholesterol levels increase sharply with national income and the degree of urbanization.
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Food deserts in the United States are most commonly found in low-income and predominately African American neighbourhoods.
One study on food deserts in
Denver, Colorado found that, in addition to minorities, the affected neighbourhoods also had a high proportion of children and new births. In children, urbanization is associated with a lower risk of
under-nutrition but a higher risk of being
overweight
Being overweight or fat is having more body fat than is optimally healthy. Being overweight is especially common where food supplies are plentiful and lifestyles are sedentary.
, excess weight reached epidemic proportions globally, with mo ...
.
Asthma
Urbanization has also been associated with an increased risk of asthma as well. Throughout the world, as communities transition from rural to more urban societies, the number of people affected by asthma increases. The odds of reduced rates of hospitalization and death from asthmas has decreased for children and young adults in urbanized municipalities in Brazil. This finding indicates that urbanization may have a negative impact on population health particularly affecting people's susceptibility to asthma.
In low and middle income countries many factors contribute to the high numbers of people with asthma. Similar to areas in the United States with increasing urbanization, people living in growing cities in low income countries experience high exposure to air pollution, which increases the prevalence and severity of asthma among these populations. Links have been found between exposure to traffic-related air pollution and allergic diseases.
Children living in poor, urban areas in the United States now have an increased risk of morbidity due to asthma in comparison to other low-income children in the United States. In addition, children with croup living in urban areas have higher hazard ratios for asthma than similar children living in rural areas. Researchers suggest that this difference in hazard ratios is due to the higher levels of air pollution and exposure to environmental allergens found in urban areas.
Exposure to elevated levels of ambient air pollutants such as nitrogen dioxide (NO
2), carbon monoxide (CO), and particulate matter with a diameter of less than 2.5 micrometers (PM
2.5), can cause DNA methylation of CpG sites in immune cells, which increases children's risk of developing asthma. Studies have shown a positive correlation between ''Foxp3'' methylation and children's exposure to NO
2, CO, and PM
2.5. Furthermore, any amount of exposure to high levels of air pollution have shown long term effects on the ''Foxp3'' region.
Despite the increase in access to health services that usually accompanies urbanization, the rise in population density negatively affects air quality ultimately mitigating the positive value of health resources as more children and young adults develop asthma due to high pollution rates.
However, urban planning, as well as emission control, can lessen the effects of traffic-related air pollution on allergic diseases such as asthma.
Crime
Historically, crime and urbanization have gone hand in hand. The simplest explanation is that areas with a higher population density are surrounded by greater availability of goods. Committing crimes in urbanized areas is also more feasible. Modernization has led to more crime as well, as the modern media has raised greater awareness of the income gap between the rich and the poor. This leads to feelings of deprivation, which in turn can lead to crime. In some regions where urbanization happens in wealthier areas, a rise in property crime and a decrease in violent crime is seen.
Data shows that there is an increase in crime in urbanized areas. Some factors include per capita income, income inequality, and overall population size. There is also a smaller association between unemployment rate, police expenditures and crime. The presence of crime also has the ability to produce more crime. These areas have less social cohesion and therefore less social control. This is evident in the geographical regions that crime occurs in. As most crime tends to cluster in city centers, the further the distance from the center of the city, the lower the occurrence of crimes are.
Migration is also a factor that can increase crime in urbanized areas. People from one area are displaced and forced to move into an urbanized society. Here they are in a new environment with new norms and social values. This can lead to less social cohesion and more crime.
Physical activity
Although urbanization tends to produce more negative effects, one positive effect that urbanization has impacted is an increase in physical activity in comparison to rural areas. Residents of rural areas and communities in the United States have higher rates of obesity and engage in less physical activity than urban residents.
Rural residents consume a higher percent of fat calories and are less likely to meet the guidelines for physical activity and more likely to be physically inactive.
In comparison to regions within the United States, the west has the lowest prevalence of physical ''inactivity'' and the south has the highest prevalence of physical ''inactivity''.
Metropolitan and large urban areas across all regions have the highest prevalence of physical activity among residents.
Barriers such as geographic isolation, busy and unsafe roads, and social stigmas lead to decreased physical activity in rural environments.
Faster speed limits on rural roads prohibits the ability to have bike lanes, sidewalks, footpaths, and shoulders along the side of the roads.
Less developed open spaces in rural areas, like parks and trails, suggest that there is lower walkability in these areas in comparison to urban areas.
Many residents in rural settings have to travel long distances to utilize exercise facilities, taking up too much time in the day and deterring residents from using recreational facilities to obtain physical activity.
Additionally, residents of rural communities are traveling further for work, decreasing the amount of time that can be spent on leisure physical activity and significantly decreases the opportunity to partake in active transportation to work.
Neighbourhoods and communities with nearby fitness venues, a common feature of urbanization, have residents that partake in increased amounts of physical activity.
Communities with sidewalks, street lights, and traffic signals have residents participating in more physical activity than communities without those features.
Having a variety of destinations close to where people live, increases the use of active transportation, such as walking and biking.
Active transportation is also enhanced in urban communities where there is easy access to public transportation due to residents walking or biking to transportation stops.
In a study comparing different regions in the United States, opinions across all areas were shared that environmental characteristics like access to sidewalks, safe roads, recreational facilities, and enjoyable scenery are positively associated with participation in leisure physical activity.
Perceiving that resources are nearby for physical activity increases the likelihood that residents of all communities will meet the guidelines and recommendations for appropriate physical activity.
Specific to rural residents, the safety of outdoor developed spaces and convenient availability to recreational facilities matters most when making decisions on increasing physical activity.
In order to combat the levels of inactivity in rural residents, more convenient recreational features, such as the ones discussed in this paragraph, need to be implemented into rural communities and societies.
Mental health
Urbanization factors that contribute to
mental health can be thought of as factors that affect the individual and factors that affect the larger social group. At the macro, social group level, changes related to urbanization are thought to contribute to social disintegration and disorganization. These macro factors contribute to social disparities which affect individuals by creating perceived insecurity. Perceived insecurity can be due problems with the physical environment, such as issues with personal safety, or problems with the social environment, such as a loss of positive self-concepts from negative events. Increased stress is a common individual psychological stressor that accompanies urbanization and is thought to be due to perceived insecurity. Changes in social organization, a consequence of urbanization, are thought to lead to reduced social support, increased violence, and overcrowding. It is these factors that are thought to contribute to increased stress.
It is important to note that urbanization or population density alone does not cause mental health problems. It is the combination of urbanization with physical and social risk factors that contribute to mental health problems. As cities continue to expand it is important to consider and account for mental health along with other public health measures that accompany urbanization.
Changing forms
Different forms of urbanization can be classified depending on the style of architecture and planning methods as well as the 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 urbanization 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. It has contributed to the phenomenon of
shrinking cities experienced by some parts of the industrialized world.
Rural migrants are attracted by the possibilities that cities can offer, but often settle in
shanty towns and experience extreme poverty. The inability of countries to provide adequate housing for these rural migrants is related to
overurbanization, a phenomenon in which the rate of urbanization grows more rapidly than the rate of economic development, leading to high unemployment and high demand for resources.
In the 1980s, this was attempted to be tackled with the urban bias theory which was promoted by
Michael Lipton.
Most of the urban poor in developing countries unable to find work can spend their lives in insecure, poorly paid jobs. According to research by the
Overseas Development Institute pro-poor urbanization will require labour-intensive growth, supported by labour protection, flexible land use regulation and investments in basic services.'
Suburbanization
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. This networked, poly-centric form of concentration is considered by some emerging pattern of urbanization. It is called variously
edge city (Garreau, 1991), network city (Batten, 1995), postmodern city (Dear, 2000), or
exurb, though the latter term now refers to a less dense area beyond the suburbs. Los Angeles is the best-known example of this type of urbanization. In the United States, this process has reversed as of 2011, with "re-urbanization" occurring as ''suburban flight'' due to chronically high transport costs.
Planned urbanization
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
Infrastructure is the set of facilities and systems that serve a country, city, or other area, and encompasses the services and facilities necessary for its economy, households and firms to function. Infrastructure is composed of public and priv ...
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 afterwards 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
The American Planning Association (APA) is a professional organization representing the field of urban planning in the United States. APA was formed in 1978, when two separate professional planning organizations, the American Institute of P ...
.
As population continues to grow and urbanize at unprecedented rates,
new urbanism and
smart growth techniques are implemented to create a transition into developing environmentally, economically, and socially sustainable cities. Additionally, a more well-rounded approach articulates the importance to promote participation of non-state actors, which could include businesses, research and non-profit organizations and, most importantly, local citizens. Smart Growth and New Urbanism's principles include
walkability, mixed-use development, comfortable high-density design, land conservation,
social equity, and economic diversity. Mixed-use communities work to fight
gentrification with
affordable housing to promote social equity, decrease
automobile dependency
Car dependency is the concept that some city layouts cause cars to be favoured over alternate forms of transportation, such as bicycles, public transit, and walking.
Overview
In many modern cities, automobiles are convenient and sometimes nec ...
to lower use of
fossil fuel
A fossil fuel is a hydrocarbon-containing material formed naturally in the Earth's crust from the remains of dead plants and animals that is extracted and burned as a fuel. The main fossil fuels are coal, oil, and natural gas. Fossil fuels m ...
s, and promote a
localized economy. Walkable communities have a 38% higher average GDP per capita than less walkable urban metros (Leinberger, Lynch). By combining economic, environmental, and social sustainability, cities will become equitable, resilient, and more appealing than
urban sprawl that
overuses
land, promotes
automobile use, and segregates the population economically.
Urbanization throughout the world
Presently, most countries in the world are urbanized, with the global urbanization average numbering 56.2% in 2020.
However, there are great differences between some regions; the nations of Europe, the Middle East and the Americas are predominantly urbanized. Meanwhile, two large belts (from central to eastern Africa, and from central to southeast Asia) of very lowly urbanized countries exist, as seen on the map here. These labeled countries are among the least urbanized.
As of 2020, urbanization rates are over 80% in the
United States,
Canada,
Mexico,
Brazil,
Argentina,
Chile,
Japan
Japan ( ja, 日本, or , and formally , ''Nihonkoku'') is an island country in East Asia. It is situated in the northwest Pacific Ocean, and is bordered on the west by the Sea of Japan, while extending from the Sea of Okhotsk in the north ...
,
Australia
Australia, officially the Commonwealth of Australia, is a Sovereign state, sovereign country comprising the mainland of the Australia (continent), Australian continent, the island of Tasmania, and numerous List of islands of Australia, sma ...
, the
United Kingdom,
France,
Spain and
South Korea.
South America is the most urbanized continent in the world, accounting for more than 80% of its total population living in urban areas. It is also the only continent where the urbanization rate is over 80%.
See also
Historical
*
Neolithic Revolution
The Neolithic Revolution, or the (First) Agricultural Revolution, was the wide-scale transition of many human cultures during the Neolithic period from a lifestyle of hunting and gathering to one of agriculture and settlement, making an incre ...
*
Oppidum
*
Polis
*
Urban revolution
Regional
*
Urbanization in Africa
*
Urbanization in China
*
Urbanization in India
*
Urbanization in Pakistan
*
Urbanization in the United States
References
Further reading
*
* Bairoch, Paul. ''Cities and economic development: from the dawn of history to the present'' (U of Chicago Press, 1991)
online review* Goldfield, David. ed. ''Encyclopedia of American Urban History'' (2 vol 2006); 1056pp
Excerpt and text search*
* Lees, Andrew. ''The city: A world history'' (New Oxford World History, 2015), 160pp.
* McShane, Clay. "The State of the Art in North American Urban History," ''Journal of Urban History'' (2006) 32#4 pp 582–597, identifies a loss of influence by such writers as Lewis Mumford, Robert Caro, and Sam Warner, a continuation of the emphasis on narrow, modern time periods, and a general decline in the importance of the field. Comments by Timothy Gilfoyle and Carl Abbott contest the latter conclusion.
External links
Website of the United Nations Population Division
Urbanization in BulgariaNASA Night Satellite Imagery– City lights can provide a simple, visual measure of urbanization
Geopolis research group, University of Paris-Diderot, France
by
Lewis MumfordThe World System urbanization dynamics by
Andrey Korotayev
Brief review of world socio-demographic trendsincludes a review of global urbanization trends
World Economic and Social Survey 2013 United Nations Department of Economic and Social Affairs.
{{Authority control
Human migration
Industrial Revolution
Land use
Urban development