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

GROUP 6, SESSION B: METHODS, TOOLS, DATABASES 8 th Int. Conference on LCA in the
Agri-Food Sector, 1-4 Oct 2012
181. Uncertainty analysis in a comparative LCA between organic and
conventional farming of soybean and barley
Monia Niero * , Alessandro Manzardo, Sara Toniolo, Filippo Zuliani, Antonio Scipioni
CESQA (Quality and Environmental Research Centre), University of Padova, Department of Industrial Engineering,
Via Marzolo 9, 35131 Padova, Italy, * Corresponding author. E-mail: monia.niero@unipd.it
There are several methods based on different approaches to quantify and analyse uncertainty (Lloyd and
Ries, 2007). One of the main advantages of the uncertainty analysis method used within Ecoinvent database
(Frischknecht et al., 2005) is to determine a correlation between data quality and the uncertainty of LCIA
results (Cooper and Kahn, 2012).
The objective of this research is to test the effectiveness of the uncertainty analysis methodology developed
by Scipioni et al. (2009) in the case of a comparative Life Cycle Assessment. The uncertainties on the LCA
input come from a qualitative assessment by data quality indicators based on the pedigree matrix. The research
considered two different cultivation techniques: organic (system A) and conventional (system B)
farming of a 3-year crop cycle for the production of soybean in the first and third year and barley in the second
year of the triennial crop. The LCA study was conducted in accordance with the ISO 14040 standards
(ISO 2006a,b), using the ReCiPe 2008 methodology for the LCIA step (Goedkoop et al., 2008). The functional
unit was 1 kg of seeds, composed respectively by 2/3 kg of soybean from first and third years of the 3year
cycle and 1/3 kg of barley from second production year. The results of the comparison between the two
farming systems at damage category level (Fig. 1.)
Concerning the damage category resources, conventional farming presents higher impacts than organic, because
of the resources (oil and gas) used in the production of triple superphosphate and urea fertilisers. On
the other hand the damage to ecosystems is higher for organic farming, because of the lower crop yields.
Within human health end-point category results, it is controversial to determine which is the best option,
because of the minor differences among the two farming systems. The first step of the uncertainty analysis
allowed the selection of the main parameters contributing to the uncertainty for both the systems under study,
through a contribution analysis at the damage assessment level, with 1% cut-off and the assignment of a
probability distribution. The most influencing input data for the human health category are shown in Table 1.
The second step included the quantitative uncertainty analysis through Monte Carlo simulation (10 3 iterations),
considering the number of comparison runs in which organic farming (A) is larger than conventional
farming (B) (Fig. 2).
The methods developed by Scipioni et al. (2009) showed its effectiveness when applied to comparative LCA.
The results confirmed that for human health there are no significant differences among the two farming systems.
Finally, the application of the two step methodology for the quantification of uncertainty connected
with the results allowed to define to which extent the LCIA results at damage level are reliable.
References
Cooper, J.S., Kahn E., 2012. Commentary on issues in data quality analysis in life cycle assessment. Int J
Life Cycle Assess doi10.1007/s11367-011-0371-x.
Frischknecht, R., Jungbluth, N., Althaus, H.J., Doka, G., Dones, R., Heck, T., Hellweg, S., Hischer, R., Nemecek,
T., Rebitzer, G., Spielmann, M., 2005. The ecoinvent database: overview and methodological
framework. Int J Life Cycle Assess 10 (1), 3–9.
Goedkoop, M., Heijungs, R., Huijbregts M, De Schryver, A., Struje, J., van Zelm, R., 2009. ReCiPe 2008. A
life cycle impact assessment method which comprises harmonised category indicators at the midpoint and
then endpoint level. First edition, Report I: Characterisation.
ISO, 2006a. Environmental management. Life cycle assessment. Principle and Framework. ISO 14040:2006.
International Organization for Standardisation, Geneva, CH.
ISO, 2006b. Environmental management. Life cycle assessment. Requirements and Guidelines. ISO
14044:2006. International Organization for Standardisation (ISO), Geneva, CH.
Lloyd, S.M., Ries, R., 2007. Characterizing, Propagating, and Analyzing Uncertainty in Life-Cycle Assessment.
A Survey of Quantitative Approaches. J of Ind Ecol 11(1), 161-179.
Scipioni, A., Mazzi, A., Niero, M., Boatto, T., 2009. LCA to choose among alternative design solutions: The
case study of a new Italian incineration line. Waste Manege 29, 2462–2474.
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