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Causes of Urban Growth

Urban global population will grow to 4.9 billion by 2030, while rural

population is expected to only increase by around 28 million.

Urban population of Africa and Asia expected to double from 2000 to

2030

1. Natural growth

More births than deaths

- Lower mortality, however this is dependent on the location, ex. Harlem

has lower mortality rates than Bangladesh on average

- Over the last 30 years, natural growth has seen to be responsible for 60%

of the urban growth

- Rural fertility leads to urban migration

2. Migration

Long term relocation of people to a location outside of thecommunity of origin. (International migration includes

labour, refugees and undocumented)

- May be confused by temporary migration

- How did it start? New job opporutnities motivated mass movements,

providing cheap labour for factories. Currently, due to globalisation,

circumstances are similar in developing countries

o Concentration of investment in city -> attracks migrants -> surplus

labour force -> low wages

o Urban poverty serves benefit of global capital

- Consider the push and pull factors living in rural areas, esp. on small

farm, it is difficult to improve standard of living beyond basic sustenanceas living id dependent on unpredictable environmental conditions;

whereas in cities, money and services are centralised so social mobility is

possible

- A pull factor is employment: people seek jobs, but often in the informal

sector

- A pull factor are the plethora of health services and amenities, like better

education: yet favelas/shanty towns/ barrios have situations

- A push factor is the industrialisation of the rural community

o Developing nations are industrialising right now, so growth rate of

urban population is very high

o

In industrialised countries, 80% of population already live in

urban areas

o Unemployment/ lack of need for labour

- A push factor is political persecution

- More women tend to migrate often ending up with low skill domestic

work.

o In South East Asia and Latin America, women cite economic

opportunity as the main reason for migrating 68% in Bangkok,

70% in the Philippines, 56% in Malaysia and over 50% in Costa

Rica, Mexico, Guatemala and Haiti

o

May be a survival method of large families to send daughters awaywho will probably send money back home

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o Also as girls education increases they have growing independence

Problems caused by urban growth

Uncontrolled urban growth resulting in sprawlenvironmental problem

o Increase traffic, saps resources and destroys urban space

o

More fuel consumption as more travel from suburbia to centralcity, traffic gridlock

o Electricity cost from extending and maintaining system further

from generator, more power lost in distribution

o Decreases forest area, farmland, woodland but also breaks up

what is left into chunks that disrupt ecosystems. Roads, power

lines and piplines cut through natural areas

o Loss of agricultural land means loss of fresh local food sources,

loss of habitat and species diversity

o Urban growth is set to consume 7 million acres of farmland, 7

million acres of environmentally sensitive land and 5 million acres

of other land during 2000 - 25

Difference between the way urbanisation occursin developing and

developed countries.

o Megacities of developing worlds has huge urban sprawl, many live

in slums or in urban periphery in poverty and degraded

environments. These high density settlements are often highly

polluted lack of services (water, sewer, trash pickup, electricity

or paved roads). Cities STILL provide people with more

opportunities and access to resources to transform their situation

Strains capacity to provide key servicesenergy, education, health care,

transportation, sanitation and physical security, as governments have lessrevenue to spend on the basic upkeep of cities and provision of services

o Sprawl requires more infrastructure, as it takes more roads, pipes,

cables and wires to service low-density areas

o Waste, recyclables, mail and street cleaning are more costly

o Public transit is impractical because the density needed support it

is not there

Rapid development of housing and infrastructure means lack of timefor

proper planning

Increase in temperatureof the cities

o Urban heat islands, caused by dark surfaces on roadways and

rooftops, absorbing heat from sunlight and rereadiated as IR

radiation)

o Also caused by lack of vegetation that would provide shade and

cool the air through evapotranspiration

o Therefore, sprawl causes an expansion of the heat island effect in

geographical extent and intensity. Especially true if development

features lots of tree-cutting and road construction

o FURTHERMORE, sprawl involves a positive feedback loop to

aggravate the problem, as there is more automobile travel, leading

tomore fuel combustion, more CO2, more climate change. Climate

change may intensify heat island effecto Number of habitants proportional to effect

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o Heat stroke, heat edema, heat tetany

Increase in air pollution due to cars (urban sprawl encourages this)

o Inhibit plant growth, create smog and acid rain, contribute to

global warming and cause health problems

o Seems low-density urban growth/sprawl contributes

o

Increased temperature leads indirectly to more pollution, asdemand for fans , coolers, air conditioners rises so power plants

have to increase their output

o Breathing problems, skin diseases

Impact on water quality

o Rainwater and snowmelt cant soak into ground to replenish

groundwater aquifers

o Urban areas in flood-prone areas, have more run-off therehfore is

an increased flood hazard

o Extra water from run-off during heavy rain can damage vegetation

and habitats along riverbanks, or lead to an increase in water

pollution from runoff contaminated by gardem chemicals, motor

oil and road salts

o These pollutants can be absorbed by humans when we eat fish

affected by this or drinking from contaminated surface water

Effects on public and social health

o Loss of community

Exploitationof workers

o Prostitution

o Child labour

o Informal sector has little security

POSITIVES TO GROWTH

Economic production

Opportunities for underemployed and unemployed

Better lifestyles

Extend better basic services (trasnporation, sewer and water) and other

specialist services (health and education) when controlled

Solutions to issues caused by growth