It's well known that vehicles contribute to harmful air pollution in busy towns and cities.

We can see and smell those fumes. But cars and lorries also pump out damaging carbon dioxide, which you can't see or smell. That carbon dioxide is building up in the earth's atmosphere like a greenhouse - heating up the earth, and causing unpredictable changes in our climate.

If we don't all start reducing those carbon dioxide emissions, we can expect an increasing number of gale force winds and torrential downpours - more and heavier floods like those experienced in and around York last year.

In the UK, every year, road transport emissions are responsible for around 25 per cent of the UK's carbon dioxide (CO2). And that proportion is growing - fast.

Today, there are 31 million vehicles on the roads of Britain, of which the vast majority are cars. According to official road traffic forecasts, this number is likely to increase by 50 per cent within 30 years.

Seventy per cent of car journeys are trips to and from work; 20 per cent are the school run'. But taking into account the fact that more than a quarter of all journeys are of less than two miles, do we really need to get out the car keys as often as we do?

There are plenty of alternatives for most people to using the car: cycling, walking, public transport, lift-sharing, or tele-working'. The City of York Council and many other authorities are working hard to promote realistic alternatives to using the car so often.

While technology can help reduce the carbon dioxide produced by individual motor vehicles, it will also need a change in attitudes to travel and car use to create a lasting, sustainable solution.

So look to your own transport policy - it's only by understanding the problem and working together that we can make a difference.