Requirements on Consumer Information about Product ... - ANEC

Consumer Information about PCF
LCA cannot eliminate uncertainty
“Due to the iterative nature of LCA, decisions regarding the data to be included shall be
based on a sensitivity analysis to specify their significance. This analysis may result in
exclusion of life cycle stages or of inputs and outputs that lack significance to the results of
the study, or otherwise in inclusion of new unit processes, inputs and outputs that are shown
to be significant. Nevertheless, there is always a danger of missing important flows. Data
gaps of bottom-up LCAs can reach up to 50% of the total environmental exchanges
(Christiansen et al. 2006). Another barrier of including all relevant data and primary data
origin are the extraordinary charges which implies again (monetary) resources and time.
Combined with the problems mentioned in the paragraphs above, this situation provides a
severe hurdle to use LCA for product differentiation purposes in environmental labelling:
Since it might not be feasible to provide an undisputable data base for product labelling, LCA
cannot eliminate uncertainty. This is especially severe when the competitive nature of
environmental labelling is considered: Especially in product groups with only little latitude for
product differentiation this will very likely lead to inquiries and complaints by disadvantaged
producers. While this could on the one side lead to massive additional data flows towards the
labelling scheme administration (which might overburden its capacity), judicial steps
questioning the scope, system boundaries and data quality are also likely. At best, such legal
disputes will slow down the labelling process.” Prakash 2008
Uncertainties occur in LCA as well as in PCF studies, there is no principal difference. They
result from several sources. According to de Koning et al (2009) three types of uncertainties
can be distinguished in LCA models:
• Parameter uncertainty: uncertainty in observed or measured values used as input
model.
• Model uncertainty: uncertainty about the way the interaction between technosphere
and biosphere has to be modelled.
• Scenario uncertainty: relates to choices made in constructing scenarios. Typical
choices include choice of impact assessment method and allocation
Using the example of two detergents de Koning et al (2009) showed for the carbon footprint
that depending on the extent different parameters to calculate the PCF are fixed or left open
to the person / institution performing the PCF the results differ. The more parameters are
fixed the fewer uncertainties could be observed and vice versa. Additionally, the uncertainties
are further reduced if the same person actually performs the study for the products to be
compared. The actual results of the comparison of one compact and one liquid detergent
were quite different depending on the approach and could even lead to contradictory
statements.
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