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Urban Environments

Urbanisation

Definition: An increasing percentage of a country’s population comes to live in towns and cities. It may involve both rural–urban migration and natural increase.

Urbanisation is occuring most rapidly in developing countries.

The fastest growing cities are in Asian, African and Latin American countries. These regions have been experiencing high population growth rates and large scale movements of people to cities seeking better economic opportunitites.

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Figure G1: Urban Landscape, New York

Inward Movements

Rural to Urban Migration

Centripetal (inward) movements occur when people move from rural areas to urban areas

Push factors are the negative aspects about a place/location that cause people to leave.

Pull factors are the positive factors about places that attract people to them.

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Figure G2: Rural to Urban Push & Pull Factors

Outward Movements

Counter-Urbanisation

Definition: The movement of population away from inner urban areas to a new town, a new estate, a commuter town or a village on the edge or just beyond the city limits/rural–urban fringe.

Counter-urbanisation is resulting in cities becoming more expansive. You should know these two terms:

Suburbanisation: The growth of towns & cities to include (engulf) surrounding villages/ rural areas.

Urban Sprawl: Unplanned & uncontrolled spread/growth of a city into the surrounding rural area.

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Figure G3: Counter-Urbanisation Push & PUll Factors

Decentralisation

Definition: The movement of shops, offices and industry from urban centers edge of town or rural locations.

The decentralisation of offices and retailing due to the factors shown in figure G4 contributes to counter-urbanisation.

As workplaces and services become located on the egde of towns, it makes more sense for people to live in the suburbs/satelite villages. High car ownership and ring roads make commuting to these locations relatively quick and easy.

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Figure G4: Decentralisation Push & Pull Factors

The Global Megacity

Megacities

Defintion: cities with a population over 10 million

Objective: Explain the global increase in the number and location of megacities

Tasks

  1. Scroll through the interactive timeline showing the growth of global cities (embedded chart G1). Describe the changing number and location of global megacites through time. Click here to go to the source page
  2. Suggest reasons for the changing pattern shown
  3. Open and progress through the timeline in this interactive Guardian article. Make notes about the examples given.
Embedded Chart G1: Growth of global cities

Land Use Models

Concentric Ring Model; Burgess

Quick summary

This model dates back to the 1960s and was based on Chicago.

CBD: the oldest and central part of the city. It is the most accessible part of the city- transport routes lead inwards to it. It is home to the main retail, banking and office buildings (many shops have offices above them on the higher floors). See figure G for more detail about the CBD.

During industrialisation and the rapid inward migration of people looking for work the city expanded and industry located around the CBD. In many developed countries the original heavier industry has been replaced with light manufacturing and distribution firms.

The workforce employed in the industries lived close by, in generally high density cheaper housing (flats or terraced streets)

Over time and with growing affluence the city expands. Larger houses with gardes and drives for cars are built around the existing housing forming the suburbs - residents are generally slightly wealthier and likely to own a car.

The wealthier residents live on the outskirts of the city in large detached houses close to the countryside

Limitations

  • The model is fairly basic and based on a specific city in a developed country.
  • It assumes that land and resources are equal in all directions - which is rarely true (mountains, rivers, coasts etc majorly influence the land-use pattern in many cities).
  • Environmental factors such as prevailing wind direction and pollution from industry are often a factor in where residential zones are located
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Figure G ; Illustrated Concentrc Ring Model

Sector Model; Hoyt

This model introduced the idea that lines of transportation would have a significant impact on land-use zoning.

Industry is likely to locate along routes of transportation (road and rail) to receive raw materials and to deliver the final product.

Workers in these industries were likely to live close the industries (lack of transport and perhaps accomodation provided by the industries).

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Figure G ; Hoyt Sector Model

CBD Core & Frame

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Figure G ; CBD Core and Frame Functions

Brownfield Land

Definition: Abandoned, derelict or under‑used industrial buildings and land that may be contaminated but have potential for redevelopment.

Tasks

Read factfile - UK brownfield sites

Why are brownfield sites often more expensive to develop than greenfield land?

UK brownfield development issues (2001)

Example 1:London Olympic Park

Read the following articles and make notes about the site of the olympic park - where, clean-up required, benfits to the area: pdf article, olympic site.

Example 2: Battersea Powerstation, London

Read this Guardian article and watch the video opposite, make short notes about what the original use was and the new land use due to redevelopment.

What are the concerns about the redevelopment of the powerstation?

Video G:
Video G:

Land Use Models

Formal Job Sector

This is the official sector of employment. Workers benefit from regulated hours, holidays and sick pay. They contribute to state pensions and benefit from social security policies.

Working in the formal sector makes it much easier to secure bank loans (buy cars, houses, start businesses etc).

The formal sector is more difficult to enter - workers usually need evidence of education or qualifications and a recognised permanent address. A bank account is also neccessary for getting paid in most cases.

formal employment taxi driver
Formal Employment: New York Taxi Driver

Informal Job Sector

This is the unofficial sector, is wide ranging and plays an important role in many urban areas.

The formal sector lacks the financial security of the formal sector, is unregulated in terms of working conditions and safety. Workers in this sector dont contribute to state schemes such as pensions and health care.

Despite the risks of being employed in the informal sector it provides much needed opportunity for many of the poorest residents, especially those in slums/favelas.

In LEDCs the informal sector plays a vital role in recycling waste material and reducing the waste going to landfill sites.

Read this article

  1. Describe the scale of the informal sector in Columbia
  2. Describe the problems faced by workers in this sector
  3. What benefits of working in this sector are mentioned?
  4. Explain how the informal economy can offer a route out of poverty for people.
  5. Read this pdf for homework
informal sector
Figure Fake DVD selling

Urban Heat Islands

You should be able to explain the causes of higher temperatures and modified local climatic features in urban areas.

Factors such as the change in the albedo rate due to roads and buildings, the heat released from transport, the leakage of heat from buildings (heating and air conditioning).

Other factors to consider are things such as changes in the levels of humidity due to the loss of vegetation and the rapid draining of surface water out of the area. Changes in wind speed and flow due to building design (Chicago is a good example).

  1. Use this link to explain in more detail the causes of urban heat islands.
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Figure G ; Urban heat Island, New York

Urban Stress

Urban areas suffer from pressure due to their nature of dense populations.

  • Crime: increased levels as rich and poor live in close proximity and there are often extremes of both rich and poor.
  • Traffic congestion: rapid urban expansion and the increase in car ownership has left many urban areas struggling to keep traffic flowing.
  • Air pollution: air pollution in many cities has been deteriorating. Industry, car ownership and in many developing urban areas the use of charcoal for cooking all contribute. Beijing Smog
  • Refuse: urban areas produce vast amounts of domestic and industrial waste. Developed countries increasingly invest in collection and recycling of domestic waste. In many developing countries official waste collection does not function as effectively and pollution is an increasing concern.
  • Housing: rapid rising demand often outstrips the ability to increase supply of housing. This results in price increases (London) and/or illegal settlements emerging (favelas in Rio).

Guardian 2015 article looking at the patterns of use and urban stresses for 4 major global cities. Some good information about comparative densities and transport networks.

You should be able to describe and explain examples of urban stress, supporting your answers with examples.

Use the videos and links to make case study notes.

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Traffic congestion: Kigali, Uganda
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Sustainable City Index

Cities around the globe in both developing and developed countries are facing many challenges due to their size and the resources that they consume.

Their populations are increasingly aware of the health issues caused by pollution (water, air and and noise). International agreements have been established to reduce different types of pollution and fines for failure may be imposed. Traffic congestion, over-crowding ,poverty and crime are examples of social issues that need to be addressed to improve the functioning of urban areas.

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Cities as Systems

Linear Systems

inputs—energy, water, people, materials, products, food

outputs—solid, atmospheric and liquid waste, noise, people.

Inputs are consumed and waste sent for disposal, ususally in landfill or incineration.

IB Geography, urban environments, linear city systems
Figure G: Linear City System

Circular Systems

Reducing, reusing and recycling the resources that the city consumes lead to less inputs and less outputs, shrinking their urban ecological footprint and increasing their sustainability.

This circular approach can be applied by households, industry and local governments/councils.

Be able to discuss strategies and impacts with examples.

IB Geography, urban environments, circular city system
Figure G: Circular City Systems
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