In the street today I notice a Suzuki Alto car, which is part of the GoGet Share Car scheme. This is a good example of how to use computers and telecommunications for improving the environment. After joining the GoGet scheme you book a car online and open it with an electronic key. This allows inner city residents to convinently share a car. Residents are more likely to forgo car ownership and use public transport if they have access to a share car when required. Also most of the cars such schemes use are small fuel efficient models, like the Suzuki Alto.
This is an example of reducing greenhouse gas emissions without the need for a large investment in new technology. The care share system uses conventional petrol powered cars and roads. There is a small investment needed in a web based booking system and the electronic keys for the cars. However, this is minor compared to the cost, for example, of electric cars or a metro system.