Walk a part of your journey to/from school where you would normally take public transport.
Why? - Cycling and walking are viable alternatives to the use of private cars or public transport, and are completely emission free forms of getting from 'A' to 'B'. They are, in fact, as yet the only readily available ways of transportation that produce absolutely no emissions.
It is shown that walking and cycling are sustainable, healthy alternatives to using forms of transport that produce harmful carbon emissions.
Carbon emissions, such as Carbon Dioxide, are very harmful to the environment, and are one of the main causes of Global Warming. Additionally, Carbon Monoxide, which is released from cars, is toxic. It joins onto your blood cells and prevent that cell from passing vital oxygen around your body.