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
782
85. LCA in organic and conventional product comparison: a review
Matthias S. Meier 1,* , Christian Schader 1 , Franziska Stoessel 2
1 FiBL - Research Institute of Organic Agriculture, Ackerstrasse, CH-5070 Frick, Switzerland, 2 ETH Zurich,
Institute of Environmental Engineering, Schafmattstrasse 6, CH-8093 Zurich, Switzerland, Corresponding
author. E-mail: matthias.meier@fibl.org
Life cycle assessment (LCA) is an important assessment tool to evaluate the environmental impacts of agricultural
products. One focus of assessments within agriculture has been the comparison of organic and conventional
production systems to evaluate whether organic or conventional agricultural products are more
environmental friendly. In different studies it has been shown that organic farming has benefits for the environment
when focusing on the farming practice (e.g. Mondelaers et al. 2009). However, when using LCA to
calculate impacts on a per unit product basis organic products show higher impacts for certain categories
mostly due to lower yields. If they are calculated per area*time unit basis the impact is lower due to lower
inputs of agricultural means. Though, there are studies showing a better performance of organic products for
both functional units (e.g. the global warming potential of milk in Cederberg and Mattsson (2000) or
Hörtenhuber et al. (2010)). Basically, there are two reasons for contradicting results of LCA studies comparing
organic versus conventional products: Firstly, real differences in performance of organic and conventional
products (from farm to farm and supply chain to supply chain) secondly, methodological artifacts
within LCA. To elucidate these presumed reasons we reviewed LCA studies on organically and conventionally
grown products of different product groups (fruits and vegetables, cereals, dairies and meat), systematically
analysing the parameters listed in Table 1.
We identified shortcomings on different levels that impair the comparison of LCA studies between organic
and conventional products. The most stringent is that system-specific characteristics of organic agriculture
are not fully reflected on the inventory level, which can lead to bias in certain impact categories (e.g.: climate
change, eco-/human toxicity, photo-oxidant formation, acidification and eutrophication). This is either due to
a lack of data or due to insufficient data quality. For example calculations of nitrous oxide emissions do not
consider the different transformation processes of organic fertilisers (which act mainly via the soil N pool)
but treat them as mineral fertilisers; heavy metal contents of manure from organic farms are based on measurements
of manure from conventional agriculture; or carbon sequestration usually is not included or the
interdependence of the C- and N-fluxes in soils is not reflected. Further, currently used allocation rules
within the livestock sector (milk and meat) seem to bias LCA results from organic and conventional production
systems (Flysjö et al. 2012). Since milk and meat production are interlinked and changes in the one production
will affect environmental impacts in the other system expansion should be used instead of allocation.
On the LCIA-level, environmental impact categories such as soil quality and functional biodiversity, which
are important impact categories for the analysis of agricultural systems, are not considered when comparing
organic and conventional agriculture products. We conclude based on present LCAs that an inter-comparison
of products from organic and conventional agricultural products is difficult and improvements can be
reached on the inventory and impact assessment level. With such adaptions LCA can become even more
important to evaluate the environmental impacts of agricultural products.
References
Cederberg, C., Mattsson, B., 2000. Life cycle assessment of milk production - a comparison of conventional
and organic farming. J. Clean. Prod. 8, 49-60.
Flysjö, Anna , Christel Cederberg, Maria Henriksson, and Stewart Ledgard. 2012. The interaction between
milk and beef production and emissions from land use change e critical considerations in life cycle assessment
and carbon footprint studies of milk. J. Clea. Prod. 28, 134-142.
Hörtenhuber, S., Lindenthal, T., Amon, B., Markut, T., Kirner, L., Zollitsch, W., 2010. Greenhouse gas
emissions from selected Austrian dairy production systems - model calculations considering the effects of
land use change. Renewable Agric. Food Syst. 25, 316-329.
Mondelaers, K., Aertsens, J., Van Huylenbroeck, G., 2009. A meta-analysis of the differences in environmental
impacts between organic and conventional farming. Br. Food J. 111, 1098-1119.