Every time you hop aboard a jet, you are about to make your own, massive, contribution to global warming. Mark MacKenzie explores a way to offset the damage by contributing to green projects

The term "offsetting" is one we usually associate with mortgages and bank accounts; robbing Peter to pay Paul in order to restructure personal finances. But now it might just help to save the planet from the environmental damage caused by global tourism. The Climate Care Trust was established in 1998 with the aim of offering people the chance to develop a "climate-neutral" lifestyle. To negate the carbon dioxide emissions created through modern living - driving, domestic heating and air travel in particular - paying customers can offset a given volume of CO2 generated by investing in a scheme to fund emissions reductions elsewhere in the world. From promoting fuel-efficient cooking stoves in Bangladesh to subsidising energy-saving light bulbs in St Lucia, "Climate Care is about paying someone else to clear up your rubbish," says Mike Mason, the trust's chairman and founder.

Tourism's main offending refuse is the many tons of CO2 poured into the atmosphere each year by commercial aircraft, the total of which is unknown. "The contribution when flying abroad isn't reported because international flights fall outside the Kyoto Protocol," Mason explains. At a conservative estimate, he puts the annual increase in aviation emissions at around 8 per cent globally. To put this into context, Mason cites a report from the Royal Commission on Environmental Pollution which warns that in order to prevent "environmental catastrophe", Western economies would have to reduce emissions by a minimum of 60 per cent in the next 50 years.

Purchasing Climate Care's products, known as offsets, is relatively straightforward. Log on to the website (climatecare.org) and an "emissions calculator" will tot up how many tons of CO2 will be created by travelling on a particular airline route. One person travelling return from London to Melbourne, for example, will produce 4.7 tons of CO2 . To counteract this pollution, Climate Care estimates it will need to invest £35 in one of its nine projects in the developing world, such as restoring the rainforest of Uganda and installing cleaner and more efficient stoves in Honduras. Punch in your credit card details and your conscience is clear.

"Is this some middle-class, guilt-assuaging indulgence or are we delivering the goods?" asks Mason. "The fact is the climate doesn't care if emissions savings come from your aeroplane or a factory in outer Mongolia. This is a step towards a time when each of us will be personally accountable for the CO2 we create." So who is signing up now? "Eighteen months ago we were offsetting around 2,000 tons of carbon emissions annually," says Mason. "This year we aim to increase that to 20,000 tons. That's equivalent to over 100 million passenger kilometres or about 50 full jumbo jet flights to New York." This increase in volume is reflected in the increased funding available for offsetting projects. "The funds available in 2005 were around £560,000; this year it should be close to £1m," says Mason.

But doesn't paying into a private scheme absolve airlines of any responsibility? "Airlines only fly to [a particular destination] because you want to go there," says Mason. "Air passengers are desperately price sensitive and the reality is that most of us don't want them to include the cost of offsetting in the price of a ticket. If they did, most of us would fly with someone else." That said, Mason is in discussions with British Airways, one airline that does offer an offsetting scheme, albeit a small one.

"At some point in the future we will have to accept the concept of personal carbon rationing," Mason says.

"The Kyoto Protocol is a good thing but in practical terms it's about as useful as giving an elephant a throat lozenge."

More information from Climate Care on 01865-207 000; climatecare.org