Ethical travel insurance lets you 'offset' your flight with a donation. Mark MacKenzie reports

Reducing your "carbon footprint", the CO2 emissions generated every time you travel by plane, is an idea appealing to increasing numbers of conscientious travellers. The principal way of doing this is "offsetting" - paying a premium on the cost of your flight that specialist organisations then re-invest in energy-saving projects. Where the argument comes unstuck is that if you're genuinely concerned about saving the planet then the best solution is not to travel at all.

But the appeal of distant shores makes such a dramatic move unlikely for all but the firmest few, so offsetting is, for the time being, as good as it gets. Last month saw the launch of Climatesure, the latest offsetting innovation in the form of the world's first "green" travel insurance policy. In 2005, Britons spent an estimated £600m on travel insurance. What Climatesure claims sets it apart is that factored into your premium is a donation to one of the global offsetting projects run by Climate Care, a British offsetting organisation.

"International travel is a part of our lives we're not likely to give up any time soon," says Climatesure's director Phil Denman. "If you want to make a difference, you can either stand Canute-like on the runway at Heathrow Airport or do something practical by making your flight 'carbon neutral'."

Over the next two years, Climatesure hopes to sell "somewhere in the region of 10,000 policies" and says response thus far has been "small but steady". Mr Denman says this is due in part to an inevitable flaw in Climatesure's campaign. "To offer competitive premiums and contribute to offsetting projects, something's got to give," he explains. "In our case that's the advertising budget."

Instead, Climatesure is relying on what Mr Denman refers to as an "ideas-orientated" marketing strategy: using the word-of-mouth common among ethical consumers.

"The concept of green insurance is an interesting development," says Malcolm Tarling of the Association of British Insurers. "Obviously it taps into a genuine concern about the environment, but it's a very competitive marketplace."

Climatesure therefore aims to keep it simple, offering three products (single-trip, annual multi-trip, backpacker), all with the same level of cover. Offset contributions are based on the average time a policyholder is likely to spend in the air, roughly four hours on European policies and 16 for worldwide. In terms of how much cash finds its way into offsetting projects, a week-long, £15 European policy provides a £2 donation, while a £120 annual family multi-trip policy generates £30.

"The main thing is that products give adequate cover," says Mr Tarling. Climatesure policies are underwritten by high-street names such AXA and Norwich Union and, according to Mr Denman, compare favourably with better-known providers. "Our message is: why wouldn't you buy Climatesure when for a competitive price you can encourage responsible tourism?"

Mr Denman believes the insurance industry views green customers as a below-average risk group. "The thinking is that if people take a responsible attitude towards their planet, they're likely to take a responsible attitude to their belongings. The ethical traveller is less likely to leave behind a camera through absent-mindedness or crash a car through recklessness." (Climatesure also offers motor insurance.)

But Mr Tarling is cautious. "Insurers are looking for the reliable consumers, but when you travel things happen, whether you're a green consumer or not."

The scheme will inevitably draw critics, with some suggesting that all the company is really selling are indulgences that will lead to more flights. But Mr Denman disagrees. "We're simply offering consumers the chance to alleviate the carbon costs of their consumption."