3.3 Lessons for the Classification and Integration …
51
n I P O F j =
I P O F j
I P O F re f , j
(3.5)
The globe is in many cases the most suitable reference system, because a single
product may also have global coverage of waste emission and resource extraction in
today’s globalized economy (Guinée et al. 2002). However, for some region-specific
impacts, the reference system can specify by a continent scale-like Europe or North
America (Hauschild et al. 2013; Laurent et al. 2012). The footprints for the reference
are usually calculated through inventorying the emissions and extractions of the
reference system and subjecting it to the same footprint calculations:
IPOF ref ,j =
i
M ref ,i × cf ij
(3.6)
By translating abstract impact results into relative contributions of the product
to a reference situation, the normalized footprint results (e.g., yr) allow for a direct
comparison between impact categories at a broader context. Nevertheless, the sum of
normalized footprint results could still be environmentally irrelevant so long as it is
not placed in an adequate context (Sleeswijk et al. 2008). For this reason, normalization is often followed by a weighting step in which the footprints of multiple impact
categories are integrated into a single composite metric. We name this metric as
composite footprint index CFI, which is equal to multiplying the normalized results
with footprint weighting factor fwf j for footprint j:
CFI =
j
nIPOF j × fwf j
(3.7)
Unlike inventory weighting, footprint weighting in most cases cannot be replaced
by a characterization approach given the difficulty of encompassing the full characteristics of divergent environmental impacts without the assistance of any subjective trade-off; with few exceptions, however, such as exergy-based characterization
(Huysman et al. 2015). It means that in general value-based weighting is unavoidable when integrating a set of IPOFs into the CFI. This supports, to some extent,
that a science communication intended to serve decisions must involve both facts
and values (Dietz 2013). The procedure for deriving weighting factors is beyond the
scope of this chapter; see Ahlroth et al. (2011) for an overview.
Finally, as visualized in Fig. 3.2, our proposal for the three-step framework makes
a novel contribution to the area and is inherently different from the one that aims to
bring together all footprints into LCA, because this framework can be operationalized
without a life cycle approach, like for instance what is needed for an organization
environmental footprint (OEF) (Fang and Heijungs 2014b) and, in reverse, doing
an LCA does not necessarily follow the inventory-characterization-normalizationweighting (ICNW) logic, like in LCA for EcoDesign (Karlsson and Luttropp 2006).
51
n I P O F j =
I P O F j
I P O F re f , j
(3.5)
The globe is in many cases the most suitable reference system, because a single
product may also have global coverage of waste emission and resource extraction in
today’s globalized economy (Guinée et al. 2002). However, for some region-specific
impacts, the reference system can specify by a continent scale-like Europe or North
America (Hauschild et al. 2013; Laurent et al. 2012). The footprints for the reference
are usually calculated through inventorying the emissions and extractions of the
reference system and subjecting it to the same footprint calculations:
IPOF ref ,j =
i
M ref ,i × cf ij
(3.6)
By translating abstract impact results into relative contributions of the product
to a reference situation, the normalized footprint results (e.g., yr) allow for a direct
comparison between impact categories at a broader context. Nevertheless, the sum of
normalized footprint results could still be environmentally irrelevant so long as it is
not placed in an adequate context (Sleeswijk et al. 2008). For this reason, normalization is often followed by a weighting step in which the footprints of multiple impact
categories are integrated into a single composite metric. We name this metric as
composite footprint index CFI, which is equal to multiplying the normalized results
with footprint weighting factor fwf j for footprint j:
CFI =
j
nIPOF j × fwf j
(3.7)
Unlike inventory weighting, footprint weighting in most cases cannot be replaced
by a characterization approach given the difficulty of encompassing the full characteristics of divergent environmental impacts without the assistance of any subjective trade-off; with few exceptions, however, such as exergy-based characterization
(Huysman et al. 2015). It means that in general value-based weighting is unavoidable when integrating a set of IPOFs into the CFI. This supports, to some extent,
that a science communication intended to serve decisions must involve both facts
and values (Dietz 2013). The procedure for deriving weighting factors is beyond the
scope of this chapter; see Ahlroth et al. (2011) for an overview.
Finally, as visualized in Fig. 3.2, our proposal for the three-step framework makes
a novel contribution to the area and is inherently different from the one that aims to
bring together all footprints into LCA, because this framework can be operationalized
without a life cycle approach, like for instance what is needed for an organization
environmental footprint (OEF) (Fang and Heijungs 2014b) and, in reverse, doing
an LCA does not necessarily follow the inventory-characterization-normalizationweighting (ICNW) logic, like in LCA for EcoDesign (Karlsson and Luttropp 2006).