Carbon and Water Footprints

Summary
The objective of this study is to analyse the origins and characteristics of the carbon and water footprints in order to understand their similarities and differences and to derive lessons on how society and business can adequately build on the two concepts. We compare the two concepts from a methodological point of view and discuss response mechanisms that have been developed, with the hope that experiences in one field might be able to benefit the other. The carbon and water footprint concepts were introduced about a decade ago, simultaneously, but independently from one another. The ‘carbon footprint’ concept has become popular over the past few years – since, more or less, 2005 – and is currently widely accepted and used by the public and media despite its lack of scientifically accepted and universally adopted guidelines: it describes greenhouse gas emission measurement from the narrowest to the widest sense. Several calculation methods and approaches for carbon footprint accounting have been proposed and are being used. Since about 2008, ‘water footprint’ has also become a popular term. Although the meaning and methodology of the water footprint were well defined in the scientific literature in the early stages of its inception, there is still an immense potential for less rigorous usage of the term, similar to the fate of the carbon footprint. The ambiguity around the concept of the carbon footprint could become a problem for the water
footprint concept in the near future. By drawing lessons from the history and progress of the carbon footprint and understanding the development and mechanisms of carbon footprint assessment (both accounting and response formulation), we can help reduce the risk that the water footprint will lose its strict definition, interpretation and usage.