4
1 General Introduction
3. Footprints are indicators that include a supply chain or that even take a full life
cycle perspective, i.e., indicators that only look at impacts of a country, company,
for instance, without including at least the upstream impacts would be disqualified
from the footprint family with this categorization.
4. Footprints are indicators that apply to the macro, economy-wide scale, in contrast
to, for instance, LCA that studies one functional unit (e.g., kg) of a product.
5. Footprints are indicators that have the word “footprint” in their name. This criterion is based on an accidental nomenclature but many footprint users implicitly
stick to. It excludes, for instance, those studies that account for water footprint
but refer to this as virtual water or embodied water.
It is necessary to recognize further that a single footprint indicator may differ
from another that has the same name but a different logic. For instance, the difference between volumetric water footprint and scarcity-based water footprint has
been a subject of intense debate (Berger and Finkbeiner 2013). This highlights the
importance of categorization in systematizing the footprint family—a topic that has
grown in interest in recent years ( ˇ
Cuˇ cek et al. 2012). In addition, while integrating
different footprint results, by using weighting factors, into a single composite metric
is appealing from a user-perspective, the scientific robustness and certainty of such
a step are disputable, as any weighting schemes inevitably involve subjective judgments and are therefore prone to a lot of uncertainty (Huppes et al. 2012). The core
of this challenge is the trade-offs between aggregate and disaggregate measures of
environmental footprints (Fang and Heijungs 2015).
1.4 The Relation to Life Cycle Assessment
Discussions on the close connection between environmental footprints and LCA
have spawned an enormous literature (e.g., Hoekstra 2015; Lenzen 2014). A large
number of pilot studies have provided concrete evidence of how LCA frameworks, in
particular life cycle impact assessment (LCIA), allow various footprint indicators to
be suited for environmental impact assessment (EIA) (e.g., Castellani and Sala 2012;
Huijbregts et al. 2008). Given that the footprint community has indeed learned and
borrowed much from LCA knowledge, some LCA experts argue that all footprint
accounts should be exclusively on an LCA basis (Ridoutt et al. 2015), in the hope that
the much broader appeal of footprint indicators could, in turn, facilitate the diffusion
of life cycle thinking, particularly for non-LCA experts (Ridoutt and Pfister 2013;
Weidema et al. 2008). In that case, LCA is meant to replace or supersede all other
footprinting methods and to be the “golden standard”.
However, the relationship between environmental footprints and LCA is not as
simple as it may seem. While being similar in many key elements, environmental
footprints differ from LCA in that they can be operationalized in contexts where
there is no clear life cycle or even without an LCA. This can be exemplified by the
case of the NFA calculations, where data gaps constitute a major challenge to the
1 General Introduction
3. Footprints are indicators that include a supply chain or that even take a full life
cycle perspective, i.e., indicators that only look at impacts of a country, company,
for instance, without including at least the upstream impacts would be disqualified
from the footprint family with this categorization.
4. Footprints are indicators that apply to the macro, economy-wide scale, in contrast
to, for instance, LCA that studies one functional unit (e.g., kg) of a product.
5. Footprints are indicators that have the word “footprint” in their name. This criterion is based on an accidental nomenclature but many footprint users implicitly
stick to. It excludes, for instance, those studies that account for water footprint
but refer to this as virtual water or embodied water.
It is necessary to recognize further that a single footprint indicator may differ
from another that has the same name but a different logic. For instance, the difference between volumetric water footprint and scarcity-based water footprint has
been a subject of intense debate (Berger and Finkbeiner 2013). This highlights the
importance of categorization in systematizing the footprint family—a topic that has
grown in interest in recent years ( ˇ
Cuˇ cek et al. 2012). In addition, while integrating
different footprint results, by using weighting factors, into a single composite metric
is appealing from a user-perspective, the scientific robustness and certainty of such
a step are disputable, as any weighting schemes inevitably involve subjective judgments and are therefore prone to a lot of uncertainty (Huppes et al. 2012). The core
of this challenge is the trade-offs between aggregate and disaggregate measures of
environmental footprints (Fang and Heijungs 2015).
1.4 The Relation to Life Cycle Assessment
Discussions on the close connection between environmental footprints and LCA
have spawned an enormous literature (e.g., Hoekstra 2015; Lenzen 2014). A large
number of pilot studies have provided concrete evidence of how LCA frameworks, in
particular life cycle impact assessment (LCIA), allow various footprint indicators to
be suited for environmental impact assessment (EIA) (e.g., Castellani and Sala 2012;
Huijbregts et al. 2008). Given that the footprint community has indeed learned and
borrowed much from LCA knowledge, some LCA experts argue that all footprint
accounts should be exclusively on an LCA basis (Ridoutt et al. 2015), in the hope that
the much broader appeal of footprint indicators could, in turn, facilitate the diffusion
of life cycle thinking, particularly for non-LCA experts (Ridoutt and Pfister 2013;
Weidema et al. 2008). In that case, LCA is meant to replace or supersede all other
footprinting methods and to be the “golden standard”.
However, the relationship between environmental footprints and LCA is not as
simple as it may seem. While being similar in many key elements, environmental
footprints differ from LCA in that they can be operationalized in contexts where
there is no clear life cycle or even without an LCA. This can be exemplified by the
case of the NFA calculations, where data gaps constitute a major challenge to the