Carbon footprinting requires the use of a Life Cycle Analysis to assess the inputs (e.g. materials and energetic resources) and outputs (i.e. methane, nitrous oxide, kg CO2 –e), from the point of production of raw materials to the disposal of the product/service.

The issue is that different countries and companies have different ways to calculate this. It is all about interpretation of what these processes are and the boundaries established.

The Carbon Trust, a private company set up by the UK government in 2001 to accelerate the move to a low carbon economy, developed a carbon footprint methodology. For those interested it can be found in their website:
http://www.carbontrust.co.uk

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