What do Sienna Miller, Tony Blair, Josh Hartnett and Prince Charles all have in common? Besides the fact that they have a lot more money than most of us will see in a lifetime, they have all spent some of that income on a "tonne of cool," an initiative through Global Cool that accepts money to offset carbon emissions.

Offsetting operates under the concept that by donating money to certain organizations, measures such as planting a tree, can be taken to undo the damage caused by activities that aren't very environmentally friendly like excessive flying or driving. The opposition to these types of programs claim that no organization can guarantee the future of a tree or a piece of land, and ultimately, this is not a solution to curbing the problem of climate change. Instead, they say offsetting simply behavior that is destructive to the environment and once the damage is done, no amount of money or planted trees will solve the problem.

"Taking a dodgy accounting proposition, which is that you can somehow identify the amount of carbon that any given new bit of forest picks up out of the atmosphere and sequesters, and make that correspond somehow to emissions elsewhere," is how Greenpeace sees carbon offsetting, according to its senior climate adviser Charlie Kronick. "It can't be done. The methodology is poor, and the logic isn't very good either. Once the carbon you've put in from fossil fuels is up there, nothing is going to make it go away."

Instead these experts recommend people actually make an effort to reduce their emissions rather than buy their way out of them.

obin Oakley, Greenpeace's climate and energy campaigner, agrees: "The issue with offsetting is that, fundamentally, it doesn't undo the damage done by carbon pollution. The vast number of players in the offsetting market are not reducing emissions in any accountable or measurable way."

 They are being misled," says Oakley. "Most carbon offsetting companies are making a killing."

Because most offsetting companies are for-profit, they lack guidelines that outline exactly how and where their money is used. In fact, indigenous people often suffer the effects of carbon projects such as new plantations, and face invasion of their land, the destruction of their homes and crops and the destruction of traditional resources.

"Turning the forest into just another commodity is not going to protect the climate or the lives of the people who live there," says Kronick.

Instead of offsetting try...

- Look into organizations such as Survival International and the Forest Peoples Programme, which assist indigenous communities in protecting their rights and their habitat.

- Rather than buying "a tonne of cool," visit the Global Cool website to find how how you can reduce your emissions using tangible measures such as turning off lights when you leave a room, turning the heat down and powering down your computer at night.

- Ensure an organization is non-profit if you are determined to buy offsets. While the money you give to one of these organizations may not save trees, it will likely benefit initiatives such as communities making the transition from fossil fuel to alternative, earth-friendly types of power.

» The Independent