24
2 A Conceptual Framework for Constituting a Footprint Family
quantifying the ecological footprint at the macro-scale have been implemented
including the NFA-NPP, IOA, MEA, emergy analysis, and exergy analysis. For
instance, IOA can facilitate the calculation of a national ecological footprint of
different categories of final demand (Tukker et al. 2009). A micro- or mesoscale ecological footprint often benefits from the component-based (bottomup) or compound-based (top-down) approaches. Moreover, since LCA is more
comprehensive in terms of coverage of impact categories but neglects the limits
of renewable capacity supplied by the biosphere (i.e., biocapacity), studies have
recommended to give priority to combining the ecological footprint and LCA in
a complementary way so that more robust and detailed sustainability assessment
could be achieved (Castellani and Sala 2012; Huijbregts et al. 2008).
(b) The NFA and its variation, NFA-PLUM, are the most common options for the
organizational- or national-level energy footprint analysis. However, unlike the
ecological footprint, many of the alternative approaches mentioned above are not
available for the energy footprint. Moreover, from a methodological perspective,
there is a great need to clarify which key features distinguish the energy footprint
from the carbon footprint. It is our conviction that the most crucial difference
between them is that the energy footprint takes a further step in translating the
amount of CO 2 emissions into the amount of biologically productive land and
water required to absorb these emissions than does the carbon footprint (Fang
et al. 2013).
(c) Given the widespread acceptance of LCA in carbon footprinting, it has almost
become the preferred method for measuring the product-level carbon footprint
(Wiedmann and Minx 2008). However, limitations hampering the application
of LCA have been observed in terms of boundary settings and responsibilitysharing among the organizational or national carbon footprints, with the particular argument that a full life cycle perspective does not allow both producers and
consumers to evaluate their footprints without double counting (Lenzen et al.
2007; Peters 2010). Currently, there are a growing number of studies on hybrid
approaches for companies or sectors, which combine the strengths of both LCA
and IOA in order to cover a broader scope of organizations and their activities
(Heijungs and Suh 2002).
(d) In the water footprint analysis the bottom-up and top-down approaches both
serve as major supporting tools. The former is accumulated item by item by
multiplying all products and activities consumed by the respective water needs
for those commodities. In some cases, it appears to be more reliable than the
latter (Van Oel et al. 2009) which is, on the contrary, calculated as the total
use of freshwater plus the gross virtual-water import minus the gross virtualwater export (Hoekstra 2009), resembling the NFA of the ecological footprint.
Furthermore, the NFA has been argued to be a special case of generalized physical input–output formulation (Kitzes et al. 2009). Therefore, it seems reasonable to make a deduction from a broad point of view that the NFA and IOA are
designed in a similar way.
2 A Conceptual Framework for Constituting a Footprint Family
quantifying the ecological footprint at the macro-scale have been implemented
including the NFA-NPP, IOA, MEA, emergy analysis, and exergy analysis. For
instance, IOA can facilitate the calculation of a national ecological footprint of
different categories of final demand (Tukker et al. 2009). A micro- or mesoscale ecological footprint often benefits from the component-based (bottomup) or compound-based (top-down) approaches. Moreover, since LCA is more
comprehensive in terms of coverage of impact categories but neglects the limits
of renewable capacity supplied by the biosphere (i.e., biocapacity), studies have
recommended to give priority to combining the ecological footprint and LCA in
a complementary way so that more robust and detailed sustainability assessment
could be achieved (Castellani and Sala 2012; Huijbregts et al. 2008).
(b) The NFA and its variation, NFA-PLUM, are the most common options for the
organizational- or national-level energy footprint analysis. However, unlike the
ecological footprint, many of the alternative approaches mentioned above are not
available for the energy footprint. Moreover, from a methodological perspective,
there is a great need to clarify which key features distinguish the energy footprint
from the carbon footprint. It is our conviction that the most crucial difference
between them is that the energy footprint takes a further step in translating the
amount of CO 2 emissions into the amount of biologically productive land and
water required to absorb these emissions than does the carbon footprint (Fang
et al. 2013).
(c) Given the widespread acceptance of LCA in carbon footprinting, it has almost
become the preferred method for measuring the product-level carbon footprint
(Wiedmann and Minx 2008). However, limitations hampering the application
of LCA have been observed in terms of boundary settings and responsibilitysharing among the organizational or national carbon footprints, with the particular argument that a full life cycle perspective does not allow both producers and
consumers to evaluate their footprints without double counting (Lenzen et al.
2007; Peters 2010). Currently, there are a growing number of studies on hybrid
approaches for companies or sectors, which combine the strengths of both LCA
and IOA in order to cover a broader scope of organizations and their activities
(Heijungs and Suh 2002).
(d) In the water footprint analysis the bottom-up and top-down approaches both
serve as major supporting tools. The former is accumulated item by item by
multiplying all products and activities consumed by the respective water needs
for those commodities. In some cases, it appears to be more reliable than the
latter (Van Oel et al. 2009) which is, on the contrary, calculated as the total
use of freshwater plus the gross virtual-water import minus the gross virtualwater export (Hoekstra 2009), resembling the NFA of the ecological footprint.
Furthermore, the NFA has been argued to be a special case of generalized physical input–output formulation (Kitzes et al. 2009). Therefore, it seems reasonable to make a deduction from a broad point of view that the NFA and IOA are
designed in a similar way.