Transcript Centripetal and Centrifugal Movements

Urbanization, Centripetal and
Centrifugal Movements
IB Geography II
PART 1: URBANIZATION
Bell Ringer: Make a list of 5 valid claims relating to
patterns of urbanization you can see in the map
The Process of Urbanization
• Urbanization: the process by which 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.
Causes of urbanization
1. Rural to urban migration
2. Natural Increase
Rural – urban migration
• Rural to urban migration – result of push and pull factors
Push and pull factors
Push factors
Pull factors
Difficult/harsh climate – eg. droughts
Chance of a better life
Struggle to provide food for family
Better housing and amenities
Very low income
Chance of good jobs – higher wages,
more varied employment
High rates of population growth have put
pressure on natural resources such as
water/energy/land
Better medical/health care
Can’t afford to fertilizers to increase yields Children able to go to school
Mechanization of farming favors rich
farmer and leads to unemployment or
underemployment of poor farmer.
Natural increase
• The people that migrate into towns and cities tend to be
young resulting in high levels of natural increase
• high % of young adults = high levels of births
• Falling death rates due to improved medical care means more
babies are born than people dying, further increasing the
urban population
% urban population
World Urban Population
Elbow Partner Discussions
• Using the last two data slides, discuss this
question:
– Why are there higher rates of urbanization in
developing nations compared to developed
nations?
Graphing Global Urbanization Activity
• Step 1: Take 5 minutes to read/annotate data
set. Be sure to read definition of
agglomerations for notecards!
• Step 2: In elbow partners, answer the
following questions:
– How many urban agglomerations had a
population greater than 10 million in 1950?
Where were these urban areas?
– Describe the changes in the number and location
of urban agglomerations in 1975, 2000, and 2010.
– What changes does the UN project for 2025?
Graphing Global Urbanization Activity
• Step 3: Graph the Data.
– Create a comparative bar graph showing bars for
each of the following continents (N. America, S.
America, Europe, Asia, Africa) and different colors
for each time period in the handout
– Y axis will be number of urban areas in each time
period in each continent
Graphing Global Urbanization Activity
• Step 4: Analyze the data. In one paragraph,
answer the following prompt using data from
your graph as resources.
• Discuss changing patterns of urbanization
from 1950-2025.
PART 2: CENTRIPETAL MOVEMENTS
Centripetal Movements involve
the migration of people into
towns and cities
Urban Processes can be seen as
inward and outward movements
Inward Movement (Centripetal)
Rural to urban migration,
gentrification, re-urbanization, urban
renewal
Outward Movement (Centrifugal)
Suburbanization, urban sprawl,
counter-urbanization
Rural Push Factors
• High rates of population growth have put
pressure on natural resource such as water
and energy and reduced the size of land
holdings
• New farming technology favors the rich
farmer, but for others it leads to
unemployment or underemployment
• Migration for work is often the only option
• (See complete list of rural push factors in
yesterday’s notes)
Urban Pull Factors
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Higher wages
More varied employment
Educational opportunities
(See complete list in earlier notes)
The Consequences of Urbanization
• Economic Growth:
– Urban economies are
almost always more
productive than rural
ones
– Industrial productivity is
higher in cities.
– Cities are usually
responsible for a greater
percentage of total GDP
The Consequences of Urbanization
• Gentrification
– The Reinvestment of capital into inner-city areas.
– Improvement in residential areas
– It is a type of filtering that may lead to the social
displacement of poor people (as a place becomes
gentrified, housing prices rise and the poor are
unable to afford it– often times minorities)
The Consequences of Urbanization
– Re-urbanization: (urban
renewal) the development of
activities to increase
residential population
densities within the existing
built-up area of a city.
– This may include the
redevelopment of vacant land
and the refurbishment of
housing and the development
of new businesses.
The Consequences of Urbanization
– Brownfield Sites:
abandoned or
underused industrial
buildings and land,
which may be
contaminated but
have potential for
redevelopment
Centrifugal Movements
Centrifugal Movements
• Also known as Decentralization
• The outward movements of a population from
the center of a city towards its edge or
periphery, resulting in the expansion of a city.
Suburbanization
• Suburb: a residential area just outside the
boundaries of a city.
• Suburbanization: the outward growth of
towns and cities to engulf surrounding villages
and rural areas. This may result from the outmigration of population from the inner urban
areas to the suburbs.
Urban Sprawl
• The unplanned and uncontrolled physical
expansion of an urban area into the
surrounding countryside. It is closely linked
with the process of suburbanization.
• Good examples of Urban Sprawl include
Mexico City
• http://www.dailymail.co.uk/news/article2401975/Amazing-aerial-photos-Mexico-Citynatural-boundaries-stand-way.html
Counter-Urbanization
• A process involving the movement of
populations away from inner urban areas to a
new town, new estate, commuter town or
village on the edge or just beyond the city
limits or rural-urban fringe.
• Characteristic of wealthy cities in MEDCs
• It is a response to increasing stress of
overcrowding, congestion, pollution and
crime.
Reasons for counter-urbanization
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Increased car ownership
Increased wealth
De-industrialization
Relocation of industry/employment to rural urban
fringe
• Desire for safe, pleasant environment, the rural
ideal/utopia
• Perception of urban areas as dangerous, high
levels of crime, racial/ethnic problems – ‘white
flight’
• Change in tenure from public/renting to private
ownership. Sell property and move out.
The Consequences of Centrifugal
Movements
• Centrifugal movements involve a shift of
population and economic activity from the
center of the urban area to its periphery and
beyond, which is detrimental to the center.
• Construction of roads and buildings destroy
open space and increases air pollution
Response to Consequences
• Urban Planners have focused on ways of
reviving the urban center(urban
renewal/gentrification) and restricting new
construction in urban hinterlands
• Hinterlands: the zone surrounding a city
The Family Life Cycle
• Intra-urban population movement may
involve shifts of population during the family
life cycle.
• A person is likely to move around different
zones of city depending on their age and their
need for a house of a certain size.