Drive with a clean conscience

Go to their websites and find the carbon calculator. The motoring function allows a ready reckoning for your CO2 output reflecting two main variables, the size of the car and the mileage. You then offset tonnes of CO2 by planting trees or contributing to some other offset project, not necessarily in the UK. It costs less than you'd think, and making a two-litre Ford Mondeo carbon neutral costs £50 a year, assuming 12,000 miles – really no more than joining a breakdown service.

The trees have to reach maturity to count, so the forestry projects are carefully chosen. Thankfully they're not deadening rows of industrially planted pine trees, but mostly UK projects such as Bowden Wood in Devon, which Future Forests is helping to return to its former glory as a native English forest through the planting of indigenous broadleaf trees such as oak, ash, alder, rowan and cherry.

The first surprise is that it's not the gas guzzling supercars that are necessarily the problem, despite their very high specific output of CO2 per mile driven. Jonathan Shopley, managing director of Future Forests, explains "We're not especially bothered by the Ferrari that's driven 1,000 miles a year. The Ford Fiesta driven 20,000 a year will produce five times more CO2."

One also has to reckon with the big picture, which shows UK motorists accounting for only one third of total UK carbon emissions. Switching to an efficient boiler at home, or to a renewable energy provider, could make a bigger difference than spending thousands of pounds on a smaller car that will still produce CO2. Taking the train also leaves behind a carbon footprint, and one recent study concluded that four people sharing a diesel-powered Peugeot 406 from London to Edinburgh would emit less CO2 each than if they'd taken the train.

Meanwhile, flying is a comparatively horrific activity in global warming terms, and a family of four flying return from London to New York emit 4.88 tonnes of CO2, requiring eight trees to offset – as much in a few hours as a Bentley Flying Spur driver knocks up in a full year's driving.

Despite this the spiralling number of cars in the world – 500 million at the last estimate – are potent symbols of the global warming dilemma, and the quest to become a carbon neutral motorist is gathering pace. Greenpeace demonstrators chained themselves recently to the Land Rover production line in a non-violent protest against gas-guzzling Sport Utility Vehicles, or SUVs, suggesting that the debate has only just begun.

Presumably the same demonstrators all arrived in Radio Taxis operated by the London-based black cab operator, the first fleet operator in the UK to become completely carbon neutral. Given how conservative the average cabbie appears to be, what possessed the company to spend £100,000 a year voluntarily protecting the environment?

Andrew Herbert, commercial director, notes that several large corporate customers had begun to enquire about Radio Taxis' environmental policy. Secondly, he says, "we wanted to achieve a high profile. Of course there was a business case for doing this, and of course the decision wasn't made for purely altruistic reasons, yet we also wanted to do something really imaginative."

It is this carbon economy that the founders of a growing band of carbon neutralisation companies are so keen to foster, based on the principle that the polluter should pay, and that the only way to tackle climate change is to 'price' the pollution and then bring the bill down by reducing it.

Opponents of 'carbon sinks', as carbon sequestering projects are often described, claim to the contrary that sequestration amounts to a 'license to pollute', adding that forestry projects often create environmental problems of their own if they are merely blanket the landscape with spruce trees, and that a tree is only a temporary 'offset' given that it eventually dies. A third objection is that responsible citizens merely end up subsidising Tony Blair's Kyoto Protocol commitments, so that what they have paid for "would have happened anyway".

"What the growing CO2 sequestration business needs is government backed trading standards leading to transparency about what you are buying, how it offsets CO2 and why this offset is 'additional' to 'what would have happened anyway'," Tom Morton at Climate Care argues. Climate Care has decided to focus less on UK forestry projects than on offset programmes in developing countries where relatively small investments can reap large environmental benefits, making 'additionality' much easier to claim. Like Future Forests, CO2balance focuses on native woodland projects backed by a broader conservation theme, only planting on otherwise degraded agricultural land where free hold ownership permits long term stability.

As for the private car driver who already feels taxed to death at the petrol pump, the carbon neutralisers have heard it all before. Buying a bicycle, using public transport or adopting a more efficient car saves you petrol costs. If these alternatives are impossible, then admit your responsibilities and do something about them. Offsetting CO2 may not be a panacea, but it is a radical advance over handwringing and the sort of uneasy bad consciences that most people seem to have about their cars – it might just be the next big thing.

www.co2balance.com; www.climatecare.org.uk; www.futureforests.com