Green channel: A holiday costing the Earth?

"Green" travel means more than signing up for a conservation holiday or an exotic eco-tourism adventure. It means thinking about every step of the journey, and its impact on the planet.

Trains and planes, cars and buses: how much do you know about their relative merits? The pressure group Transport 2000 (0171-388 8386) can provide you with a "gas-o-meter" which reveals all. With some Blue Peter-style skills, you can assemble two cardboard discs and compare the pollution levels you create by travelling by car, bus, train or plane, on journeys from 1km to 1,500km.

So what are the options for skiers heading for France this winter? The new Eurostar train to Bourg St Maurice (see page 5) gives the chance to check on the impact of a 1,200-km journey from London. The gas-o-meter reveals that a journey on the new train would produce around 130kg of carbon dioxide - one of the main "greenhouse" gases. A bus would take twice as long but wreak only half the harm to the atmosphere, producing a mere 65kg of CO2.

At first sight the car appears to be the real villain, spewing 345kg of carbon dioxide into the air. But that applies to the whole vehicle, whether occupied by one person or by many. If three people drive south together, they do less harm than by train.

The confirmed individualist who insists on motoring alone does only slightly more damage than the person who flies. Taking the plane consigns 215kg of CO2 to the atmosphere.

At the moment we each generate 35kg of CO2 per week. Transport 2000 says we should reduce this to 14kg. On that scale, flying to France uses 30 weeks' worth of your ration. Better start cycling to work.