When you fly, drive or heat your home you are directly responsible for CO2 emissions. You can offset these emissions by buying carbon credits that are invested in renewable energy projects, in reforestation or in some other activity that results in a net reduction in atmospheric CO2. For every one tonne of CO2 you or your business produces, one tonne is saved somewhere else in the world. If you buy enough carbon credits you can offset all your emissions and effectively become carbon neutral.

So is anything real happening, or is it just a sop to our consciences? Well, offset projects need to meet certain criteria if the concept is to have any meaning. It is important that your payment results in emission reductions that would not have happened without your intervention, so the project's funding must be instrumental to its going ahead. This concept is known in the carbon market as ‘additionality’.

There are two main project types, VERs (Verified Emission Reductions) and CERs (Certified Emission Reductions). VER projects are developed independently of government regulations. Benefits are verified by independent third parties, and standards vary. CER projects are developed using the UN Kyoto Protocol process, the Clean Development Mechanism (CDM). The UK Government encourages investment in CERs, although the carbon reductions cost more to achieve. (i.e. it costs you more per tonne offset).

There are some question marks over carbon offsetting, not least of which is additionality (see above). Other problems include accurate measure of the emissions to be offset and of course an accurate measure of the carbon saved elsewhere. Many offset projects involve planting trees, which naturally ingest carbon, but this is a complex and unpredictable process which precludes accurate measurement. Projects that focus on energy efficiency can be even trickier. See our article on types of offset HERE for more information.

If after minimising your emissions as far as possible you choose to offset some or all of the remainder then this site's recommendation would be to look carefully into the company selling the carbon credits and the projects they are investing in. There are a lot of offset businesses and charities to choose from - see our directory HERE for a comprehensive list.