DOI: http://dx.doi.org/10.1065/lca2001.11.068 --- The option of weighting impact categories according
to ISO 14042 on Life Cycle Impact Assessment (LCIA) is particularly
difficult for global organizations, as they have to consider
a wide range of values. The motivation for employing
weighting is usually based on the desire to simplify LCIA output,
especially in circumstances where product system tradeoffs
occur. Looking globally at regional variations in legislation,
consumer values, monetary valuation, existing weighting sets
and expert opinions, no globally agreed upon weighting set is
likely to be derived. This is due to both the inherent subjectivity
of weighting and local variations in environmental imperatives.
Hence, the authors recommend that LCIA quantitative weighting,
especially those provided in pre-packaged software instruments,
should not be employed. Admittedly, to use a spectrum
of LCIA results for internal design decisions, some kind of tradeoff
analysis has to be performed, especially if comparing competing
design alternatives. However, this trade-off analysis should
be done separately from the technical LCA study and should
reflect values and visions of the global organization, as well as
the circumstances of the targeted market, in a qualitative way.
For any external communication, none of the quantitative
weighting sets can be used. |
