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) Jakarta Dhaka Karachi Lagos Mumbai Kolkata Cairo Delhi Manila Beijing Rio de Janeiro Shanghai Buenos Aires S ã o Paulo Mexico City Osaka-Kobe Tokyo Moscow Los Angeles New York Immature, rapidly growing South/southeast Asia and Africa Population under 30% urban 20%+ slums Consolidating, growing South America and southeast Asia Population 40–50% urban Under 20% slums Mature, slow growing Europe and North America Population 70%+ urban No slums
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 .
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 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 Outputs Inputs
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.
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) 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 Ways to reduce outputs Ways to reduce inputs