World Cities
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Transcript of World Cities
Going globalWorld cities
Urbanisation today and tomorrow
• By 2030, the urban population will have risen to 5 billion or 60% of the global
population.• 50% of the urban population today is aged under 25.• Asia’s urban population is set to rise from 1.4 billion now to 2.6 billion in
2030 (equivalent to the world’s total population in 1955).• Africa’s urban population will rise from 300 to 750 million and that of Latin
America and the Caribbean from 400 to 600 million.
Types of city
• Urban areas with a population of over 10 million people are termed
‘megacities’. • There were around 20 of these in 2007; 75% are in the developing world and
most continue to grow rapidly.• Strictly speaking, London is not a megacity, but if the population of the wider
metropolitan area is taken into account, it comes very close to being one.• There are around 200 ‘million cities’ with populations of over 1 million.• ‘World cities’ are those cities that wield huge economic and political power,
such as New York, Tokyo (also megacities) and London.
Urban growth
Towns and cities grow in a number of ways: • Rural–urban migration is a key process.• Rural–urban migrants tend to be young and have high fertility; this boosts rates
of natural increase in cities.• Rural–urban migration in the developing world is currently responsible for much
urban growth.• Natural increase, especially in the developing world.• In the developed world, counter-urbanisation tends to balance the influx of
migrants to towns and natural increase is low due to low fertility rates. • The more developed the megacity, the slower the rate of growth.
Megacities (1)
• Megacities are very diverse.• Some are at the early or immature stage in the cycle of urbanisation, whereas
in others the rate of growth is slowing (consolidating).• Developed world megacities (mature) tend to have very slow growth rates and
are dominated by suburban sprawl. They are increasingly feeling the effects of
counter-urbanisation.
Megacities (2)
Mature, slow growing
Europe and North America
Population 70%+ urban
No slums
Consolidating, growing
South America and southeast
Asia
Population 40–50% urban
Under 20% slums
Immature, rapidly growing
South/southeast Asia and
Africa
Population under 30% urban
20%+ slums
Osaka-Kobe
Tokyo
Moscow
Los Angeles
New York
Beijing
Rio de Janeiro
Shanghai
Buenos Aires
São Paulo
Mexico City
Jakarta
Dhaka
Karachi
Lagos
Mumbai
Kolkata
Cairo
Delhi
Manila
Future trends
• There will be a significant shifts in the
distribution and ranking of megacities,
with major cities in the poorer parts of Asia
entering the top ten list. • New cities will also gain megacity status.
By 2020 there could be close to 30
megacities, including: Istanbul,
Guangzhou, Kinshasa, Lima, Tianjin,
Lahore and Bogota.• Other rapidly growing cities likely to
exceed the 10 million mark by 2020 are:
Bangalore, Wuhan, Chennai (Madras),
Tehran, Riyadh, Hyderabad, Baghdad and
Hong Kong.
2015 population
(millions)
Tokyo 35
Mumbai 22.5
Mexico City 21
São Paulo 20.5
New York 19.9
Delhi 18.6
Shanghai 17.2
Calcutta 17
Jakarta 16.8
Dhaka 15.2
Top ten megacities, 2015 (predicted)
Slums (1)
• 60% of Mumbai’s population live in slums crammed on 6% of the city’s land. • Slums in Mumbai are growing at a rate of 2.2% per year.• The world slum population will rise from 1 billion in 2005 to an estimated 1.3–
1.4 billion by 2020.• There are two views of slums and shanty towns:
— One is that they are hotbeds of poverty and potential unrest.— The other is that, with a little effort and help, they can be improved to
provide basic housing for the city’s poor.
Increasing numbers of people live in the slums and shanty towns of the developing
world’s megacities:
Slums (2)
• Newcomers to developing world megacities face stark choices in terms of
housing. • Some inhabit ‘old’ inner city slums (e.g. Dharavi in Mumbai). • They have the ‘advantage’ of being close to available work in the city. • Alternative squatter settlements spring up on the ‘septic urban fringe’.• Many of these slums and shanties are located on dangerously steep slopes, next
to polluted rivers, on marshland or near polluting industry.
Megacity problems (1)
• Sprawling slums Developing world• Explosive population growth • Poverty and prevalence of informal economy• Lack of clean water and sanitation • Disease epidemics • Transport gridlock • Urban funding crises• Overcrowding • Lack of green space• Pollution of air and water • Gating and segregation• Visual and noise pollution• Water supply problems• Deep eco-footprints • Declining centres • Sprawling suburbs and exurbs Developed world
Megacity problems (2)
• Finding solutions to these problems is becoming increasingly difficult. • In many developing cities, growth is clearly out of control with annual rates
running at 6–8% per year in the worst cases. • Some possible solutions have been demonstrated: Curitiba in southeastern
Brazil is a well-known example and Dongtan, China’s first ‘ecocity’ is
attempting to create a sustainable urban area.
Megacity problems (3)
• An important issue is planning. This is the key to Curitiba’s success, albeit this is
only a small city of 1.8 million inhabitants.• If planners can control the growth and density of cities, they should be able to
avoid the stifling congestion of high-density cities and the sprawling mass
and high private transport use of low-density cities.
Urban resource use (1)
• As urban areas grow they become voracious consumers of resources.• This results in deep eco-footprints and a huge amount of waste. • London’s urban metabolism is shown on the next slide:
— London has a population of 7.5 million.— London recycles 18% of its waste.
Urban resource use (2)
London’s annual metabolism
Inputs Outputs
20 million tonnes of fuel, in oil equivalent
40 million tonnes of oxygen
2.2 million tonnes of paper
2.4 million tonnes of food
1 billion tonnes of clean water
360 tonnes of glass
2.1 million tonnes of plastics
1.2 million tonnes of metals
1.2 million tonnes of timber
2 million tonnes of cement
36 million tonnes of bricks, blocks, sand and
tarmac
60 million tonnes of carbon dioxide
4 million tonnes of household waste
11.4 million tonnes of industrial and
demolition waste
400,000 tonnes of sulphur dioxide
280,000 tonnes of nitrogen oxides
7.5 million tonnes of wet, digested sewage
sludge
Urban resource use (3)
To decrease the eco-footprints of urban areas and improve the quality of urban life
ways need to be found to reduce both the inputs and outputs of cities. Some
possible methods are outlined in the table below.
Ways to reduce inputs Ways to reduce outputs
Water metering and mending leaking pipes
Reducing packaging
Introducing more public transport/more efficient
vehicles
Using recycled building materials
Localising food distribution and improving
storage
Using less polluting vehicles
Using alternative (renewable) energy
sources
More recycling
Reusing and recycling water
More carbon sequestration (e.g. urban
gardens, farms and forests)