Offsets are only a start in neutralising nasty whiffs

Carbon offsetting is the phrase on the lips right now of anyone who wants to help save the planet. The theory is that you can carry on flying and polluting as long as you pay for someone else to do an environmental good deed or to cut their emissions. That way, you can repair the damage you caused in the first place.

So take that flight to New York, the argument goes, but then neutralise your carbon footprint by paying a company to help build a wind farm in Africa.

It's not only flights that can be offset. After all, we emit CO2 every time we turn on a kettle, so there's plenty of scope for consumers to take action. You can find out the exact extent of your emissions by going online and using the Department for Transport's "Act on CO2 calculator" or the "Carbon Calculator" form specialist offsetter The CarbonNeutral Company.

There are two main options if you want to clean up your own pollution. You can support green projects through dedicated firms such as The Carbon Neutral Company, Climate Care or Carbon Clear, or you can pay a bit more for flights or holidays through easyJet and lastminute.com, and the extra will help clear the air. You can, for instance, offset two and a half years' worth of your baby's nappies for 4.88 with Carbon Clear, and you can even become a "carbon neutral citizen" offset your entire annual footprint for as little as 71.32 with The CarbonNeutral Company.

Organisations that offer offsetting will look to carry out their pledge in one of two ways. First, they may use your cash to purchase carbon credits on a global market. Buying credits in effect forces businesses to reduce their emissions.

But at the launch of its flight-offsetting scheme last summer, easyJet rubbished brokers dealing in credits as "snake oil salesmen". Its argument was that brokers were charging too high an administration fee. As a result, it decided to buy carbon credits on the open market itself and sell them to passengers.

A more straightforward alternative is for the offset provider to pay for something of environmental benefit such as the wind farm in Africa or trees to be plan-ted in Norway. There is an internationally recognised accreditation for firms adopting this approach, designed by the Swiss non-profit foundation Gold Standard. Qualifying companies must use "renewable energy and energy-efficiency technologies that promise sustainable development for the local community" to move away from a "fossil-fuel dependent lifestyle".

No matter what accreditation is in place, though, the "polluter pays" concept behind offsetting has its dangers, according to environmentalists.

Dale Vince, founder of the green energy company Ecotricity, says: "It's an easy 'out.' To say my flight to New York is OK because I pay a few quid to offset my carbon is a stretch."

Alex Lambie at Greenhelpline, the renewable-energy comparison website, says too much attention is "given to offsetting, as opposed to reducing emissions". But this argument also has much to do with the plethora of schemes available, some of which are less worth while than others most notably the practice of planting trees, which is hard to measure accurately and takes too long to have any impact. Mr Vince says such schemes give "offsetting a bad name".

Don't assume that by offsetting the odd flight, you're an eco-warrior. As Mr Lambie says: "It's not a bad thing to offset but it's not a good thing if that's all you do."