Urbanization (or urbanisation) refers to the population shift from
rural
In general, a rural area or a countryside is a geographic area that is located outside towns and cities. Typical rural areas have a low population density and small settlements. Agricultural areas and areas with forestry typically are describ ...
to
urban area
An urban area, built-up area or urban agglomeration is a human settlement with a high population density and infrastructure of built environment. Urban areas are created through urbanization and are categorized by urban morphology as cities, t ...
s, 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
town
A town is a human settlement. Towns are generally larger than villages and smaller than cities, though the criteria to distinguish between them vary considerably in different parts of the world.
Origin and use
The word "town" shares an ori ...
s and
cities
A city is a human settlement of notable size.Goodall, B. (1987) ''The Penguin Dictionary of Human Geography''. London: Penguin.Kuper, A. and Kuper, J., eds (1996) ''The Social Science Encyclopedia''. 2nd edition. London: Routledge. It can be def ...
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
Urban sprawl (also known as suburban sprawl or urban encroachment) is defined as "the spreading of urban developments (such as houses and shopping centers) on undeveloped land near a city." Urban sprawl has been described as the unrestricted growt ...
. 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
A developed country (or industrialized country, high-income country, more economically developed country (MEDC), advanced country) is a sovereign state that has a high quality of life, developed economy and advanced technological infrastruct ...
will be urbanized. That is equivalent to approximately 3 billion urbanites by 2050, much of which will occur in Africa and
Asia
Asia (, ) is one of the world's most notable geographical regions, which is either considered a continent in its own right or a subcontinent of Eurasia, which shares the continental landmass of Afro-Eurasia with Africa. Asia covers an area ...
.
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
Urban planning, also known as town planning, city planning, regional planning, or rural planning, is a technical and political process that is focused on the development and design of land use and the built environment, including air, water, ...
,
geography
Geography (from Greek: , ''geographia''. Combination of Greek words ‘Geo’ (The Earth) and ‘Graphien’ (to describe), literally "earth description") is a field of science devoted to the study of the lands, features, inhabitants, and ...
,
sociology
Sociology is a social science that focuses on society, human social behavior, patterns of Interpersonal ties, social relationships, social interaction, and aspects of culture associated with everyday life. It uses various methods of Empirical ...
,
architecture
Architecture is the art and technique of designing and building, as distinguished from the skills associated with construction. It is both the process and the product of sketching, conceiving, planning, designing, and constructing building ...
,
economics
Economics () is the social science that studies the Production (economics), production, distribution (economics), distribution, and Consumption (economics), consumption of goods and services.
Economics focuses on the behaviour and intera ...
,
education
Education is a purposeful activity directed at achieving certain aims, such as transmitting knowledge or fostering skills and character traits. These aims may include the development of understanding, rationality, kindness, and honesty. Va ...
,
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
Public health is "the science and art of preventing disease, prolonging life and promoting health through the organized efforts and informed choices of society, organizations, public and private, communities and individuals". Analyzing the det ...
. 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
Sociology is a social science that focuses on society, human social behavior, patterns of social relationships, social interaction, and aspects of culture associated with everyday life. It uses various methods of empirical investigation and ...
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 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
Urban resilience has conventionally been defined as the "measurable ability of any urban system, with its inhabitants, to maintain continuity through all shocks and stresses, while positively adapting and transforming towards sustainability". Ther ...
and
urban sustainability
Sustainable urbanism is both the study of cities and the practices to build them (urbanism), that focuses on promoting their long term viability by reducing consumption, waste and harmful impacts on people and place while enhancing the overall wel ...
in the face of increased urbanization is at the center of international policy in
Sustainable Development Goal 11 "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
In general, a rural area or a countryside is a geographic area that is located outside towns and cities. Typical rural areas have a low population density and small settlements. Agricultural areas and areas with forestry typically are describ ...
is being rapidly replaced by predominantly
urban culture
Urban culture is the culture of towns and cities. The defining theme is the presence of a great number of very different people in a very limited space - most of them are strangers to each other but still try to be polite to each other more times ...
. The first major change in settlement patterns was the accumulation of
hunter-gatherers
A traditional hunter-gatherer or forager is a human living an ancestrally derived lifestyle in which most or all food is obtained by foraging, that is, by gathering food from local sources, especially edible wild plants but also insects, fungi, ...
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
Mesopotamia ''Mesopotamíā''; ar, بِلَاد ٱلرَّافِدَيْن or ; syc, ܐܪܡ ܢܗܪ̈ܝܢ, or , ) is a historical region of Western Asia situated within the Tigris–Euphrates river system, in the northern part of the F ...
and
Egypt
Egypt ( ar, مصر , ), officially the Arab Republic of Egypt, is a transcontinental country spanning the northeast corner of Africa and southwest corner of Asia via a land bridge formed by the Sinai Peninsula. It is bordered by the Mediter ...
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
market
Market is a term used to describe concepts such as:
*Market (economics), system in which parties engage in transactions according to supply and demand
*Market economy
*Marketplace, a physical marketplace or public market
Geography
*Märket, an ...
s 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
The Industrial Revolution was the transition to new manufacturing processes in Great Britain, continental Europe, and the United States, that occurred during the period from around 1760 to about 1820–1840. This transition included going f ...
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
England is a country that is part of the United Kingdom. It shares land borders with Wales to its west and Scotland to its north. The Irish Sea lies northwest and the Celtic Sea to the southwest. It is separated from continental Europe b ...
and
Wales
Wales ( cy, Cymru ) is a Countries of the United Kingdom, country that is part of the United Kingdom. It is bordered by England to the Wales–England border, east, the Irish Sea to the north and west, the Celtic Sea to the south west and the ...
, 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
France (), officially the French Republic ( ), is a country primarily located in Western Europe. It also comprises of Overseas France, overseas regions and territories in the Americas and the Atlantic Ocean, Atlantic, Pacific Ocean, Pac ...
, 41% in
Prussia
Prussia, , Old Prussian: ''Prūsa'' or ''Prūsija'' was a German state on the southeast coast of the Baltic Sea. It formed the German Empire under Prussian rule when it united the German states in 1871. It was ''de facto'' dissolved by an em ...
and 28% in the
United States
The United States of America (U.S.A. or USA), commonly known as the United States (U.S. or US) or America, is a country primarily located in North America. It consists of 50 states, a federal district, five major unincorporated territorie ...
.
As labourers were freed up from working the land due to higher
agricultural productivity
Agricultural productivity is measured as the ratio of agricultural outputs to inputs. While individual products are usually measured by weight, which is known as crop yield, varying products make measuring overall agricultural output difficu ...
they converged on the new
industrial cities
An industrial city or industrial town is a town or city in which the municipal economy, at least historically, is centered around industry, with important factories or other production facilities in the town. It has been part of most countries' i ...
like
Manchester
Manchester () is a city in Greater Manchester, England. It had a population of 552,000 in 2021. It is bordered by the Cheshire Plain to the south, the Pennines to the north and east, and the neighbouring city of Salford to the west. The t ...
and
Birmingham
Birmingham ( ) is a city and metropolitan borough in the metropolitan county of West Midlands in England. It is the second-largest city in the United Kingdom with a population of 1.145 million in the city proper, 2.92 million in the West ...
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
Australasia is a region that comprises Australia, New Zealand and some neighbouring islands in the Pacific Ocean. The term is used in a number of different contexts, including geopolitically, physiogeographically, philologically, and ecologica ...
and
South America
South America is a continent entirely in the Western Hemisphere and mostly in the Southern Hemisphere, with a relatively small portion in the Northern Hemisphere at the northern tip of the continent. It can also be described as the southe ...
. 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
The working class (or labouring class) comprises those engaged in manual-labour occupations or industrial work, who are remunerated via waged or salaried contracts. Working-class occupations (see also " Designation of workers by collar colou ...
.
Urbanization rapidly spread across the
Western world
The Western world, also known as the West, primarily refers to the various nations and state (polity), states in the regions of Europe, North America, and Oceania. 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
Yale University is a private research university in New Haven, Connecticut. Established in 1701 as the Collegiate School, it is the third-oldest institution of higher education in the United States and among the most prestigious in the wo ...
in June 2016 published urbanization data from the time period 3700 BC to 2000 AD, the data was used to make a
video
Video is an electronic medium for the recording, copying, playback, broadcasting, and display of moving visual media. Video was first developed for mechanical television systems, which were quickly replaced by cathode-ray tube (CRT) syste ...
showing the development of cities on the
world
In its most general sense, the term "world" refers to the totality of entities, to the whole of reality or to everything that is. The nature of the world has been conceptualized differently in different fields. Some conceptions see the worl ...
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
Suburbanization is a population shift from central urban areas into suburbs, resulting in the formation of (sub)urban sprawl. As a consequence of the movement of households and businesses out of the city centers, low-density, peripheral urba ...
, 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
Quality of life (QOL) is defined by the World Health Organization as "an individual's perception of their position in life in the context of the culture and value systems in which they live and in relation to their goals, expectations, standards ...
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
A drought is defined as drier than normal conditions.Douville, H., K. Raghavan, J. Renwick, R.P. Allan, P.A. Arias, M. Barlow, R. Cerezo-Mota, A. Cherchi, T.Y. Gan, J. Gergis, D. Jiang, A. Khan, W. Pokam Mba, D. Rosenfeld, J. Tierney, an ...
,
flood
A flood is an overflow of water ( or rarely other fluids) that submerges land that is usually dry. In the sense of "flowing water", the word may also be applied to the inflow of the tide. Floods are an area of study of the discipline hydrol ...
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 and
2007 Jakarta flood. Urban areas are also far more prone to
violence
Violence is the use of physical force so as to injure, abuse, damage, or destroy. Other definitions are also used, such as the World Health Organization's definition of violence as "the intentional use of physical force or Power (social and p ...
,
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
Agriculture or farming is the practice of cultivating plants and livestock. Agriculture was the key development in the rise of sedentary human civilization, whereby farming of domesticated species created food surpluses that enabled people to ...
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
Globalization, or globalisation (Commonwealth English; see spelling differences), is the process of interaction and integration among people, companies, and governments worldwide. The term ''globalization'' first appeared in the early 20t ...
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
The Greater Manila Area is the contiguous urbanization region surrounding the Metropolitan Manila area. This built-up zone includes Metro Manila and the neighboring provinces of Bulacan to the north, Cavite and Laguna to the south, and Rizal ...
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
The working class (or labouring class) comprises those engaged in manual-labour occupations or industrial work, who are remunerated via waged or salaried contracts. Working-class occupations (see also " Designation of workers by collar colou ...
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
ODI (formerly the 'Overseas Development Institute') is a global affairs think tank, founded in 1960. Its mission is "to inspire people to act on injustice and inequality through collaborative research and ideas that matter for people and the p ...
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
A slum is a highly populated urban residential area consisting of densely packed housing units of weak build quality and often associated with poverty. The infrastructure in slums is often deteriorated or incomplete, and they are primarily inh ...
. 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
''Whole Earth Discipline: An Ecopragmatist Manifesto'' is the sixth book by Stewart Brand, published by Viking Penguin in 2009. He sees Earth and people propelled by three transformations: climate change (global warming), urbanization and biotech ...
'', 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
Slash-and-burn agriculture is a farming method that involves the cutting and burning of plants in a forest or woodland to create a field called a swidden. The method begins by cutting down the trees and woody plants in an area. The downed vegeta ...
agriculture.
Alex Steffen
Alex Steffen (born 1968) is an American futurist who writes and speaks about sustainability and the future of the planet. He emphasizes the importance of imagining persuasive, positive possible futures: "It's literally true that we can't build ...
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 island
An urban heat island (UHI) is an urban or metropolitan area that is significantly warmer than its surrounding rural areas due to human activities. The temperature difference is usually larger at night than during the day, and is most apparen ...
s 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
Eutrophication is the process by which an entire body of water, or parts of it, becomes progressively enriched with minerals and nutrients, particularly nitrogen and phosphorus. It has also been defined as "nutrient-induced increase in phytopla ...
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 bloom
A harmful algal bloom (HAB) (or excessive algae growth) is an algal bloom that causes negative impacts to other organisms by production of natural algae-produced toxins, mechanical damage to other organisms, or by other means. HABs are sometimes ...
s, 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
Food loss and waste is food that is not eaten. The causes of food waste or loss are numerous and occur throughout the food system, during production, processing, distribution, retail and food service sales, and consumption. Overall, about o ...
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
Methane ( , ) is a chemical compound with the chemical formula (one carbon atom bonded to four hydrogen atoms). It is a group-14 hydride, the simplest alkane, and the main constituent of natural gas. The relative abundance of methane on Eart ...
gases and attraction of
disease vectors.
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
Habitat destruction (also termed habitat loss and habitat reduction) is the process by which a natural habitat becomes incapable of supporting its native species. The organisms that previously inhabited the site are displaced or dead, thereby ...
, 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
Life expectancy is a statistical measure of the average time an organism is expected to live, based on the year of its birth, current age, and other demographic factors like sex. The most commonly used measure is life expectancy at birth ...
.
Rapid urbanization has led to increased mortality from
non-communicable disease
A non-communicable disease (NCD) is a disease that is not transmissible directly from one person to another. NCDs include Parkinson's disease, autoimmune diseases, strokes, most heart diseases, most cancers, diabetes, chronic kidney disease, os ...
s associated with lifestyle, including
cancer
Cancer is a group of diseases involving abnormal cell growth with the potential to invade or spread to other parts of the body. These contrast with benign tumors, which do not spread. Possible signs and symptoms include a lump, abnormal b ...
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 disease
A contagious disease is an infectious disease that is readily spread (that is, communicated) by transmission of a pathogen through contact (direct or indirect) with an infected person.
A disease is often known to be contagious before medical s ...
s 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 settlement
Informal housing or informal settlement can include any form of housing, shelter, or settlement (or lack thereof) which is illegal, falls outside of government control or regulation, or is not afforded protection by the state. As such, the inform ...
s 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
Public health is "the science and art of preventing disease, prolonging life and promoting health through the organized efforts and informed choices of society, organizations, public and private, communities and individuals". Analyzing the det ...
,
sanitation
Sanitation refers to public health conditions related to clean drinking water and treatment and disposal of human excreta and sewage. Preventing human contact with feces is part of sanitation, as is hand washing with soap. Sanitation systems ...
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
In nutrition, diet is the sum of food consumed by a person or other organism.
The word diet often implies the use of specific intake of nutrition for health or weight-management reasons (with the two often being related). Although humans are o ...
, 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
Cholesterol is any of a class of certain organic molecules called lipids. It is a sterol (or modified steroid), a type of lipid. Cholesterol is biosynthesized by all animal cells and is an essential structural component of animal cell mem ...
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
Denver () is a consolidated city and county, the capital, and most populous city of the U.S. state of Colorado. Its population was 715,522 at the 2020 census, a 19.22% increase since 2010. It is the 19th-most populous city in the Unit ...
, 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
Mental health encompasses emotional, psychological, and social well-being, influencing cognition, perception, and behavior. It likewise determines how an individual handles stress, interpersonal relationships, and decision-making. 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 country, 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 Slum, 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
ODI (formerly the 'Overseas Development Institute') is a global affairs think tank, founded in 1960. Its mission is "to inspire people to act on injustice and inequality through collaborative research and ideas that matter for people and the p ...
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 infrastructure, urban infrastructure installed before urbanization occurs. Landscape planning, Landscape planners are responsible for landscape infrastructure (public parks, sustainable urban drainage systems, Greenway (landscape), 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.
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 to lower use of fossil fuels, 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 overexploitation, overuses land use, 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
The United States of America (U.S.A. or USA), commonly known as the United States (U.S. or US) or America, is a country primarily located in North America. It consists of 50 states, a federal district, five major unincorporated territorie ...
, Canada, Mexico, Brazil, Argentina, Chile, Japan, Australia, the United Kingdom,
France
France (), officially the French Republic ( ), is a country primarily located in Western Europe. It also comprises of Overseas France, overseas regions and territories in the Americas and the Atlantic Ocean, Atlantic, Pacific Ocean, Pac ...
, Spain and South Korea.
South America
South America is a continent entirely in the Western Hemisphere and mostly in the Southern Hemisphere, with a relatively small portion in the Northern Hemisphere at the northern tip of the continent. It can also be described as the southe ...
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
*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 Mumford
The 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
Urbanization,
Human migration
Industrial Revolution
Land use
Urban development