The word ‘Carbon’, when used within the phrase ‘carbon footprint’ is often used as a short-cut term to describe the main greenhouse gases (e.g. Carbon Dioxide - CO², Methane – CH and Nitrous Oxide – N²O) in terms of carbon dioxide equivalents. However, on occasion it is also used to refer only to CO² so it is important to clarify what is meant when the term is used.

‘Carbon dioxide equivalents’ (CO²e) is the internationally recognised way of expressing the amount of global warming of a particular greenhouse gas in terms of the amount of CO² required to achieve the same warming effect over 100 years. Methane has 23 times the global warming potential of Carbon Dioxide, whilst Nitrous Oxide has approximately 300 times the potential. So for example, 1kg of methane has the global warming potential of 23kg of CO².

‘Global warming’ is most often used to refer to the greenhouse gas effect caused by human activities. It must be recognised however that there is a natural greenhouse effect.

	Carbon Trust's original label

	Source: Carbon Trust

A ‘carbon footprint’ is the total emissions of greenhouse gases (in carbon equivalents) from whichever source is being measured – be it at an individual, organisation or product level.

‘Embedded carbon’ is the term used to describe the way in which the carbon footprint of a product, as measured by a full lifecycle assessment from ‘cradle to grave’, can be represented in terms of kg of CO² per kg of product.

The term ‘carbon label’ is used to refer to the communication of embedded carbon to consumers. The Carbon Trust has adopted a label which gives a product’s embedded carbon emissions in terms of grams of CO²e for the particular pack weight.

Why do companies calculate carbon footprints?

There is near universal consensus that greenhouse gases produced by human activity lead significantly to global warming, and its consequences.

The early incentive for some businesses to understand their footprints came in the form of the EU’s Emissions Trading Scheme (see factsheet on ‘Emissions Trading’). As companies could sell permits they did not need, they had a real incentive to understand their carbon impact (footprint) and to reduce it.

More recently, there is increasing public understanding of carbon footprints and their impact and an increased desire to buy ‘low carbon’ products and service. Indeed, Carbon Trust research reports that 66 per cent of the UK population are more likely to buy products and services with a low carbon footprint.

Many companies which have undertaken some form of carbon footprint of their operations have identified ‘hotspots’ (e.g. associated with energy use) and have been able to address these, saving both money and carbon emissions.

The drivers for food and grocery companies to understand their carbon footprints in the future are likely to be both consumer demand for lower carbon products and regulation. In the UK, within the Climate Change Act there is specific reference to introducing a mandatory scheme called the Carbon Reduction Commitment for greenhouse gas emissions which is likely to cover significant parts of the food chain.

How to calculate carbon footprints?

The traditional method of carbon management was for each company in a supply chain to focus simply on their own carbon footprint, from the operations they directly undertake. Other companies in the chain may also undertake an analysis, but possibly using a different methodology, so it was difficult to form a complete picture of the overall carbon footprint of a product.

Today, the generally accepted method used in calculating a carbon footprint is based on ‘Life Cycle Assessment’ (LCA). An LCA evaluates quantitatively the environmental impact of a product or service in each stage of its life - from ‘cradle to grave’ (or ‘cradle to cradle’ if the material is recycled for further use).

So for example, an LCA of a food product sold through a retail outlet would look at the following stages:

Life Cycle Assessment of a food product

Taking a full supply approach has a number of advantages over the traditional approach:

the analysis covers the entire supply chain for a product, and so companies must collaborate on providing information and undertaking the LCA;
the carbon savings from a full supply chain assessment can come from internal efficiency improvements or from external process change. In this sense, there are many similarities between full supply chain LCA’s and ‘Value Chain Analyses’ conducted by the Food Chain Centre.

	Carbon Trust's current label

	Source: Carbon Trust

There is an international standard which sets the necessary principles and framework, and requirements and guidelines for a LCA (ISO 14040/14044). The Carbon Trust have developed a draft methodology based on the ISO standard and is currently using it in a number of pilot projects with food and grocery (and other) companies.

For companies that go through the process and wish to, they are able to use the Carbon Trust’s consumer facing label, which gives the weight of CO²e per pack. There are rules for carbon reductions which allow the continued use of the label.

IGD’s involvement

Through our Industry Leaders’ Forum IGD has set up an Industry Working Group on Carbon Footprinting to consider all the issues from a food and grocery industry perspective.

In addition, this Group fed into the Carbon Trust’s ‘Technical Advisory Group’ which was undertaking a consultation on the Carbon Trust’s methodology throughout 2007 and 2008. At the end of 2008, the PAS (Publicly Available Specification) 2050: Assessment of the Life Cycle Greenhouse Gas Emissions of Goods and Services was launched.

PAS 2050 and the guidance document are freely available from www.bsigroup.com/PAS2050

The issue of how best to communicate the embedded carbon of products, or carbon reductions, to the general public has not (yet) been considered in detail.

Related Items on IGD.com:

Factsheets:
- Carbon Offsetting
- Emissions Trading
- Carbon Reduction Commitment

Reports:
- The Next Big Food Thing
- Food for Life

Carbon Footprinting and Labelling - Definitions

Why do companies calculate carbon footprints?

How to calculate carbon footprints?

IGD’s involvement

Related Items on IGD.com:

Related Internet links: