Corporate carbon footprint analysis in practice – With a special focus on validity and reliability issues

As a yield of efforts in the international climate policy and emerging consumer awareness there is a growing interest for the quantification of corporate level carbon footprints. As a consequence, there have been numerous initiatives, guidelines and calculation methods emerged recently to be able to quantify company level direct and indirect greenhouse gas emissions. Most of them are based on the philosophy and classification of the Greenhouse Gas Protocol. This paper intends to provide a comparison of freely available online corporate level carbon footprint calculators with a novelty value of addressing their validity and reliability. Validity here refers to the issue whether different calculators cover the same or similar aspects or scopes of the corporate carbon footprint, while reliability addresses the question whether different calculators deliver the same or similar result if we use the same input data. Based on the example of an imaginary enterprise, we argue that validity is partly achieved, while reliability of the calculators is relatively low. This means that online corporate carbon calculators can be useful to provide a first insight for companies into their carbon footprints and they can also be useful for temporal comparisons at the level of one company (if the activity of the company is not too complex.) However, these calculators do not seem to be very appropriate for comparisons among different companies or with external benchmarks.