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

GROUP 2, SESSION A: CARBON OR WATER FOOTPRINTS, SOIL, BIODIVERSITY 8 th Int. Conference on LCA in the
Agri-Food Sector, 1-4 Oct 2012
59. Environmental impact of green beans: the relevance of water use
Thomas Kägi * , Silvan Rüttimann, Fredy Dinkel
Carbotech AG, Switzerland, Corresponding author. E-mail: t.kaegi@carbotech.ch
About 80% of the world fresh water consumption is attributed to agriculture. Excessive water use can lead to
water stress, one of the major environmental challenges in the future. As fresh water is getting scarcer due to
climate change and due to increase irrigation amounts, the role of environmental impact due to water scarcity
is growing in life cycle impact assessments.
The goal of this study (Kaegi et al. 2011) was to compare different green bean production and processing
scenarios and to derive the contribution of water use to the total environmental impact. The functional unit
was 1kg of green beans, ready to eat. All relevant life cycle phases were considered including cultivation of
beans (field processes, fertiliser and chemical inputs, irrigation, direct field emissions), transportation, further
processing (such as washing and then drying or canning or freezing) and cooking of the beans. Data for bean
production was based on Lattauschke (2002) and data for direct field emissions were derived from Nemecek
& Kägi (2007). The ecoinvent inventory V2.2 database (Swiss Centre for LCA 2009) was used for other
secondary data (fertiliser production, transportation and other) and emission factors. For valuation of the
different environmental impacts (such as global warming-, acidification-, eutrophication-, ozone depletion
potential, ecological and human toxicity etc.) the ecological scarcity method (Frischknecht 2007) was used
including regional water scarcity factors for the water use.
The high water scarcity in the Spanish region where the beans are grown leads to a large environmental impact.
Beans grown in greenhouses show a similar high environmental impact due to fossil energy use for
heating. Fresh beans from Egypt are flown to Switzerland which explains the high contribution from transportation.
Further processing such as canning, freezing, drying lead to higher environmental impacts compared
to fresh beans. However, when compared to irrigated beans from Spain, this seems to be irrelevant.
If the whole life cycle of ready to eat beans is considered the water impact can play a very important role. It
contributes up to 85% of the total environmental impact in the case of beans from Spain. The implemented
water impact in nowadays life cycle assessment methods covers a crucial and important environmental topic
and helps to improve environmental consulting in the field of agriculture and water consumption.
References
Dinkel et al. (2006). Calculations for „Der kluge Einkaufswagen“ Unterrichtseinheit zu den Themen Umwelt,
Konsum, Ökobilanzen. Bundesamt für Umwelt (BAFU)
Frischknecht et al. (2008) Frischknecht R., Steiner R., Jungbluth N. (2008) Methode der ökologischen Knappheit
­ Ökofaktoren 2006. Bundesamt für Umwelt (BAFU)/ÖBU.
Lattauschke, G, 2002. Hinweise zum umweltgerechten Anbau von Freilandgemüse im Freistaat Sachsen –
Buschbohnen. Sächsische Landesanstalt für Landwirtschaft. http://www.landwirtschaft.sachsen.de/LFL
Nemecek T. & Kägi T. (2007). Life Cycle Inventories of Swiss and European Agricultural Production Systems.
Final report ecoinvent V2.0 No. 15a. Agroscope Reckenholz-Taenikon Research Station ART,
Swiss Centre for Life Cycle Inventories, Zurich and Dubendorf, CH, retrieved from www.ecoinvent.ch
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