LCA Food 2012 in Saint Malo, France! - Manifestations et colloques ...

GROUP 3, SESSION A: LABELLING, CONSUMERS, DIET 8 th Int. Conference on LCA in the
Agri-Food Sector, 1-4 Oct 2012
772
79. Bittersweet comparability of carbon footprints
Silvia Marton
myclimate – The Climate Protection Partnership, Zürich, Switzerland, E-mail: silvia.marton@myclimate.org
Comparability of results from life cycle assessments is a critical topic, especially when results are used for
communication and product labelling. The main sources of variation are (1) different system boundary definitions,
(2) data handling and assumptions, (3) different databases for background data (Kägi et al. 2011). In
our study of three types of chocolate, the carbon footprint is performed by the same person in order to eliminate
the first and second cause for variation. The carbon footprint was performed using two different tools,
Footprint Expert (FPX) of the British Carbon Trust Footprinting Company Ltd., and EMIS 5.6 from Carbotech
AG. Both tools provide an integrated database for background data, the FPX Reference Database 3.3
and ecoinvent 2.2, respectively. The calculation of agricultural products was performed with the FPX Crop
Calculator. In the EMIS model, direct emissions were calculated following the methodology used in ecoinvent
(Nemecek & Kägi, 2007) and the IPCC 2006 Guidelines. The aim of this study is to find out if the results
of the footprints are comparable or not. The study is performed according to PAS 2050. Primary data
were collected for cocoa and sugar cane farming and the production stages. Secondary data were mainly
taken from the databases of the tools.
The study shows that the final results from both tools are in the same magnitude order, with differences of
less than 15 per cent. Larger differences could be observed for the single production stages (Fig. 1 and Table
1). The calculated greenhouse gas (GHG) emissions from cocoa beans were higher using the ecoinvent
methodology compared to those from the FPX Crop Calculator. For sugarcane, the result was different, as
the emissions calculated with the ecoinvent methodology were lower than those from the FPX Crop Calculator.
GHG emissions from transport were higher when calculated with FPX compared to the transport emissions
based on ecoinvent. Especially for sea freight, ecoinvent emission factors are much lower, which is in
line with the results from other studies analysing sea freight (Emanuelsson et al. 2010).
Both tools, FPX and EMIS, have their advantages and disadvantages. FPX is a tool with a strict guideline
and especially designed for carbon footprinting. Therefore it can be used by non-professionals, allowing
them to calculate carbon footprints of good quality. The aim of FPX is to standardise carbon footprinting in
order to enable comparable results, even if footprints are performed by different organisations. However, the
tool is limited to carbon footprinting. EMIS is a tool for life cycle assessments (LCA). Therefore it can be
used for other impact categories and includes more functionality such as input-output analyses or uncertainty
analyses. It allows a more differentiated analysis of products. However, as it is more flexible in its use, comparability
of studies performed by different people is lower.
Often product carbon footprint analyses are conducted mainly for marketing reasons. It has to be emphasised
that the communication of results on product labels is a difficult topic. Indicating an exact number may be
misleading to customers, as it pretends an accuracy that cannot be achieved by current methodologies. However,
standardised tools like FPX together with an accredited certification body do provide comparable results
that may help customers to choose climate friendly products.
References
Emanuelsson, A., Skontrop Hognes, E., Ziegler, F., Sund, V., Winther, U., Elligsen, H., 2010. Life cycle
approach to Norwegian seafood logistics – new ways to model food transports, in: Notarnicola B., Settanni
E., Tassielli G. Giungato, P. (Eds.), proceedings of LCAfood 2010, Bari, Italy
Kägi, T., Wettstein, D., Schmid, H., Azapagi, A., Amienyo, D., Contreras, A., Sanchez, M., Villegas Costa,
L., Ménard, J.F., Bécaert, V., Kanzaki, M., 2011. LCA Comparative Study on Beer. 5 th PCF World Summit,
Zurich, 7-8 April 2011
Nemecek, T., Kägi, T., 2007. Life Cycle Inventories of Agricultural Production Systems. ecoinvent report
No. 15, Zurich and Dübendorf, Switzerland.