Consequences of urban growth
Urban populations are predicted to carry on growing. The continued growth of urban areas will have consequences.
Housing shortages - there won't be enough houses for everyone. This will have different effects in different places though, e.g. in developed countries children may live with their parents for longer. In developing countries more people could end up living in overcrowded shanty towns - these cause other problems like poor health, insufficient water supply and a lack of sewage removal.
Increased ecological footprints - more power will be needed as the population grows.This could mean that more fossil fuels are burnt to produce the power. This reduces the amount of fossil fuels in the future.
Transport problems - lots of people use bikes and scooters to get around in megacities in less developed countries. But as more people move in and become more affluent, car ownership will inrease. This will cause an increase in pollution and the number of accidents. Thr transport system may not be able to sope so it will become more difficult to get around the city.
Consequences of urban growth
Increased effect on climate change - more GHGs will be emitted beause power is used as the urban area grows. This could mean that climate change is accelerated.Some natural hazards are imcreasing because of climate chaneg, e.g. hydrometeorlogical hazards, which means people may be at risk.
The need to become sustainable
Sustainable development means growth in a way that lets the people living now have the things they need, but without reducing the ability of people in the future to get what they need.
Megacities require so many resources that its unlikely any megacity could ever develop in a truly sustainable way. But things can be done to make them develop in a way that's more sustainable:
- Building more carbon-neutral homes
- Generate more power from renewable energy sources
- Recycling more waste
- Water conservation schemes
- Improving public transport
Building more carbon-neutral homes
Buildings that generate as much energy as they use. They have things like solar panels to produce energy, and lots of insulation to reduce the amount of energy that's lost.
BedZED is a carbon neutral housing development in London.
Building more carbon-neitral homes provides more housing without increasing the ecological footprint of the city. However, carbon neutral homes can be expensive to build so they can't always be used to solve housing shortages.
Power from renewable energy sources
Burning fossil fuels to generate power isn't sustainable because they'll run out.
They also increase the rate of climate change because burning fossil fuels produces GHGs.
Megacities could use more power from hydroelectric power from the sources that don't run out, e.g. LA uses hydroelectric power from the Hoover Dam.
Greater energy needs can be met without increasing the ecological footprint of the city. This means people's ability to generate power in the future is less affected. However, at the moment renewable energy sources can't generate enough power on their own to support large cities.
Recycling more waste
Increased recycling means less resources are used. Less waste is produced, which reduces the amount of waste that goes to landfill.
Landfill is unsustainable because it uses up resources - finite resources that are thrown away and the resource of sustainable landfill sites.
Decomposition of landfill also releases GHGs.
Water conservation schemes
Only as much water should be taken from the environment as can naturally be replaced.
If natural stores, e.g. lakes or groundwater, are reduced too much there won't be enough for future generations.
Water conservation schemes reduce the amout of water used, but don't affect how the needs of perople using the water are met, e.g. collecting rainwater for use on gardens or installing toilets that use less water to flush,
Improving public transport
Using buses, trains and trams that generate little or no harmful emissions. The ecological footpront of the city is reduces because the buses and trains are producing less harmful emissions.
The number of buses and trains can also be increased, as well as the area they cover.
Improved public transport networks will mean fewer cars on the road, so emissions will be further decreased.
Dongtan is planned to be built on the island of Chongming, China. It's meant to be a sustainable city. The idea is to help solve the problems of urban growth in Shanghai, but in a way that will help to achieve more sustainable development.
- All the homes will produce their own power. They'll be well insulated to prevent energy loss, e.g green roofs provide good insulation.
- Dongtan will be more sustainable because it will provide housing to help Shanghai's housing shortages, but the housing won't increase energy use or deplete the resources available to the city.
Renewable energy sources:
- Power will be provided by wind turbines outside the city as well as smaller wind turbines on the buildings.
- Biofuels will also be used - generating power by burning waste biological material.
- Dongtan will be more sustainable because less energy resources will be used, but enough power will be produced to provide for the needs of the population. Using biomass to generate energy also means less waste goes to the landfill so less space is used up.
Green transport schemes:
- Vehicles that run on a petrol or diesel engine won't be allowed in the city.
- City will have a nework of cycleways, walkways and canals.
- Public transport system will use low-emission vehicles, e.g. solar-powered water taxis.
- Dongtan will be more sustainable because few eissions will be produced by the city's transport systems, but it shouldn't affect people's ability to get around the city.
Reasons why China's plans for sustainable urban living might not be achieveable:
Not enough governmental support for sustainable development - political leaders need to make and enforce laws to change the way urban areas are developed, e.g. the government hasn't renewed the planning permission for Dongtan.
It costs a lot and takes a long time to build more sustainable urban areas. Shanghai's urban growth problems may need cheaper and quicker solutions, so plans for Dongtan may be compromised to get it finished sooner.
Even if all the plans were carried out in full, Dongtan still wouldn't be truly sustainable - huge resources would be used to construct the city, and some emissions would be caused by housing and transport.
It's difficult to make existing urban areas sustainable. Even if new urban areas are made to be more sustainable, old urban areas are still unsustainable - they're using up resources and damaging the environment.