Carbon Footprinting For Beginners

Before a business can attempt to reduce its carbon emissions, it is important to measure current emissions – the famous carbon footprint reduction. The main reasons for measuring a footprint are:

o to provide a baseline against which future emissions can be compared;
o to identify ‘hotspots’ for action;
o to identify obvious quick wins during the analysis;
o to make a statement of intent to internal and external stakeholders that the company is serious about the climate change agenda.


A carbon footprint is a total amount of persistent Greenhouse Gas (GHG) associated with a person, an organisation, a country or a product.

Greenhouse Gases

The recognised 6 greenhouse gases are:

o Carbon Dioxide (CO2);
o Methane (CH4);
o Nitrous Oxide (N2O);
o Hydrofluorocarbons (HFCs);
o Perfluorocarbons (PFCs);
o Sulphur Hexafluoride (SF6).

These all have different global warming effects, so they tend to be expressed as kilogrammes or tonnes CO2 equivalent using standard conversion factors. For example, 1kg methane is equivalent to 21kg CO2. From now on I’ll refer to all of these generically as “carbon emissions”.

Scope of Carbon Footprints There are three types of carbon emissions for organisations, and four a product:

  1. direct emissions from internal operations (eg carbon dioxide and nitrous oxide from vehicle use, carbon dioxide from gas-fired heating systems);
  2. indirect emissions from electricity use (ie the carbon emissions from the power station);
  3. direct and indirect emissions from suppliers (and their suppliers) relating to the goods and services purchased; and for products:
  4. emissions from the distribution, use and disposal of the product after it has been manufactured.

This is where footprinting gets complicated and controversial. Type 3 emissions are usually very significant (eg in the NHS they make up 60% of the footprint), yet many companies, including major supermarkets, simply ignore them, as does the UK Government and many personal carbon calculators on the Internet. For example, the UK’s national emissions (types 1 & 2) are officially going down, but this is because we are offshoring our dirty industries (type 3) and our carbon footprint is actually going up. In my opinion, if you use the word ‘footprint’, you must include Type 3 emissions. This is easier said than done and will require a significant amount of data gathering – and much of that data will be held by other organisations, who may not be keen to reveal it.

Type 4 emissions are hard to calculate because predicting the lifecycle of a product is very difficult, but again it is important to include these emissions as they can often exceed the ‘cradle to gate’ emissions of types 1-3. For example, a compost company recently put a carbon label on their peat-based product with emission types 1-3, ignoring the fact that the type 4 emissions as the peat breaks down in use are 5 times as high as the rest put together.

Making Assumptions

The inclusion of indirect emissions from the entire supply chain raises one very difficult question – “Where do you stop?”. If you start to list the number of potential sources of greenhouse gases amongst your suppliers, their suppliers etc, you will soon realise that this is a very data-intensive exercise. I recommend the following shortcuts to prevent the exercise from becoming unmanageable:

o 80/20 Thinking: if the company consumes a large amount of energy-intensive material (eg Aluminium) and a tiny amount of low energy services (eg contractors who carry out an annual site audit), then it is reasonable to count the production of aluminium in and exclude the contractors.
o Use of published data: If suppliers already publish their carbon footprint then it is reasonable to use a pro-rata amount of this. Data from a study on a similar organisation as long as it is documented.