for the same offset.) Registries also clarify ownership of offsets. A serial number is assigned to each verified offset. When an offset is sold, the serial number and “credit” for the reduction is transferred from the account of the seller to an account for the buyer. If the buyer “uses” the credit by claiming it as an offset against their own emissions, the registry retires the serial number so that the credit cannot be resold.

A cheap way to wash off your sins?

Offsetting can claim several pluses. It raises people’s awareness of the issue, promotes sustainable technologies (e.g. through funding for renewable energy projects), and can offer development benefits to local communities. Above all, it reduces GHG emissions, if done correctly. But there are also inescapable drawbacks, and offsetting has some determined opponents. It is a cheap and easy way to salve your conscience without actually doing anything at all, they argue. If you can simply pay a little for the promise of future climate innocence, it will do nothing to persuade you to cut your emissions radically in the here and now. Even if the overall amount of emissions is reduced by the offsets, structures that are linked to the emissions generated in the first place remain without improvement (for example inefficient public transport systems). Inequality between those who can afford to emit and those who cannot is yet another criticism that offset supporters have to face. Carbon Trade Watch (www.carbontradewatch.org) describes offsets as “modern day indulgences, sold to an increasingly carbon-conscious public to absolve their climate sins.”

And what about future value accounting? This arises when you are sold an offset today which will actually take some time to act before the emissions are reduced. This can lead to a buyer thinking wrongly that they have already offset their emissions. And the longer the project takes to make the reduction, the more chance there is of something going wrong, with the offset perhaps never actually being achieved.

To counter these arguments, supporters of offsets argument that compared to indulgences, offsets are more than just useless promises on paper; they actually do help in saving the climate. And given that there are binding emissions targets in place, rising prices for offsets resulting from both, increasing demand as well as growing economic development, cutting our