Exposed: The Truth Behind Popular Carbon Offsetting Schemes

A television documentary has uncovered flaws in a series of carbon offsetting schemes intended to make good the global warming gases emitted by flights and other polluting activities.

An episode of the British show Dispatches aired "The Great Green Smoke Screen," which revealed how academics and environmentalists are questioning the ethics and impact of offsetting -- and suggesting that offsetting schemes have not been effective as claimed.

Two of Britain's biggest carbon offset companies, the Carbon Neutral Company and Climate Care, and offsetting schemes at BA, BP and Sky are scrutinised by the programme.

Carbon offsetting has becoming popular in recent years as a way for individuals and business to mitigate the effects of emissions, for example from cars or planes, as publicity has grown about the threat and speed of climate change.

Dispatches claims that schemes run by Climate Care, and promoted by BA, took no account of the "multiplier" effect which increased the damage done by aviation fumes in the stratosphere by a factor of three. In other words, the schemes funded by BA passengers only mitigate one third of the damage that their flights cause. Climate Care, which uses a multiplier of two on its website, told Dispatches that it was unhappy about the way Britain's biggest airline ran its scheme.

A project funded by BP to siphon methane gas from excrement at pig farms in Mexico will only produce half the savings claimed on the company's website, which is now being amended.

In Bulgaria, Sky funds a hydro-power plant that turns water into low-pollution electricity but the manager, Vladislav Tsvetkov, said that Sky's money, though welcome, was "not required" -- a view backed by the Bulgarian bank which lent the capital. The manager later retracted his comments and the Carbon Neutral Company which administers the offsets insisted the money had been critical in establishing the plant.

At Donkleywood forest in Northumberland, the Carbon Neutral Company said the planting of the trees helped the climate. But it emerged that 70 percent of the funding came from the Forestry Commission.

The programme analysed the behaviour of the electricity suppliers which offer customers the opportunity to match their bills to wind and solar power with "green tariffs" while doing no more than meeting their legal obligations to buy renewable power.

Dispatches questioned whether big companies such as HSBC and Sky had any right to claim they were "carbon neutral" as a result of buying offsets to undo the effects of their pollution. Instead the programme hinted that more should be done to limit the polluting activity in the first place.

Dieter Helm, professor of energy policy at Oxford University, told the programme: "It's very, very fashionable for big companies who are actually engaged in pretty polluting activities to somehow embrace the slogan that they have gone carbon neutral, so we can go on consuming their products knowing that actually we're not damaging the environment. If only it was that simple.

"The idea that they can assuage their consciences by buying some offsets in the international market as a substitute to cleaning up their act -- this is good perhaps PR and publicity, but substance I think is seriously lacking."