2.4 Discussion
27
area of sea space required to sustain the harvested aquatic species, while the water
footprint includes the volume of evaporated and polluted water associated with the
activity of fishing and aquaculture (Borucke et al. 2013; Hoekstra 2009). Thus, the
ecological and water footprints can be seen as two complementary indicators in
terms of fishing-related EIA. Another example is the combination of the carbon and
water footprints which can be profitably implemented as dual single-issue indicators
allowing for trade-offs without the risk of problem shifting both in the case of potable
water distribution (Del Borghi et al. 2013) and in the case of fresh tomato production
(Page et al. 2012).
However, significant double counting of the footprint family has been discerned
in terms of carbon emissions and sequestration. A partial solution is to exclude
the carbon uptake land from current ecological footprint accounting (Galli et al.
2012; Steen-Olsen et al. 2012; Van den Bergh and Verbruggen 1999). It is better to
rename the rest of the ecological footprint as “land footprint” which accounts for the
actual land and ocean exploited by humanity (Steen-Olsen et al. 2012; Weinzettel
et al. 2013). This can be justified by two arguments. First, the carbon uptake land is
hypothetical land that does not exist and thus conflicts with the actual appropriated
land within the aggregate ecological footprint account (Hubacek and Giljum 2003;
Van den Bergh and Verbruggen 1999). Second, the carbon uptake land is tightly
tied to energy-related carbon emissions and sequestration which are already covered
by the energy and carbon footprints (Fang et al. 2013; Steen-Olsen et al. 2012).
Nevertheless, there is still a need to get rid of the overlap between the energy and
carbon footprints. A potential approach for making the energy footprint completely
independent of the carbon footprint will be presented in Sect. 2.4.2.1.
2.4.1.3 Methodological Consistency
Of particular interest in evaluating the footprint family is to what extent the consistency between different footprint indicators has been maintained. From a methodological perspective, this is largely driven by two factors: standardization and harmonization. With respect to the progress of methodological standardization, several
accounting standards underlying individual footprints already exist in two internationally standardized formats (Giljum et al. 2011): the normative format (e.g., ISO,
PAS) and the descriptive format (e.g., GFN, WFN). The normative one like the ISO
never aims to standardize accounting methods in detail, and there is not even common
agreement on how to interpret some of the ISO requirements, so diverging approaches
have occurred spontaneously (Guinee et al. 2010). The descriptive one contains
numerous detailed regulations in which it seems much easier to build consensus
concerning methodology, transparency, and communications but is constrained by
weak enforcement. In addition, the methodology for the energy footprint is not yet
as standardized and scientifically robust as the cases of the ecological, carbon, and
water footprints (Galli et al. 2012); therefore, there is much room for improvement
in future studies of the energy footprint.
27
area of sea space required to sustain the harvested aquatic species, while the water
footprint includes the volume of evaporated and polluted water associated with the
activity of fishing and aquaculture (Borucke et al. 2013; Hoekstra 2009). Thus, the
ecological and water footprints can be seen as two complementary indicators in
terms of fishing-related EIA. Another example is the combination of the carbon and
water footprints which can be profitably implemented as dual single-issue indicators
allowing for trade-offs without the risk of problem shifting both in the case of potable
water distribution (Del Borghi et al. 2013) and in the case of fresh tomato production
(Page et al. 2012).
However, significant double counting of the footprint family has been discerned
in terms of carbon emissions and sequestration. A partial solution is to exclude
the carbon uptake land from current ecological footprint accounting (Galli et al.
2012; Steen-Olsen et al. 2012; Van den Bergh and Verbruggen 1999). It is better to
rename the rest of the ecological footprint as “land footprint” which accounts for the
actual land and ocean exploited by humanity (Steen-Olsen et al. 2012; Weinzettel
et al. 2013). This can be justified by two arguments. First, the carbon uptake land is
hypothetical land that does not exist and thus conflicts with the actual appropriated
land within the aggregate ecological footprint account (Hubacek and Giljum 2003;
Van den Bergh and Verbruggen 1999). Second, the carbon uptake land is tightly
tied to energy-related carbon emissions and sequestration which are already covered
by the energy and carbon footprints (Fang et al. 2013; Steen-Olsen et al. 2012).
Nevertheless, there is still a need to get rid of the overlap between the energy and
carbon footprints. A potential approach for making the energy footprint completely
independent of the carbon footprint will be presented in Sect. 2.4.2.1.
2.4.1.3 Methodological Consistency
Of particular interest in evaluating the footprint family is to what extent the consistency between different footprint indicators has been maintained. From a methodological perspective, this is largely driven by two factors: standardization and harmonization. With respect to the progress of methodological standardization, several
accounting standards underlying individual footprints already exist in two internationally standardized formats (Giljum et al. 2011): the normative format (e.g., ISO,
PAS) and the descriptive format (e.g., GFN, WFN). The normative one like the ISO
never aims to standardize accounting methods in detail, and there is not even common
agreement on how to interpret some of the ISO requirements, so diverging approaches
have occurred spontaneously (Guinee et al. 2010). The descriptive one contains
numerous detailed regulations in which it seems much easier to build consensus
concerning methodology, transparency, and communications but is constrained by
weak enforcement. In addition, the methodology for the energy footprint is not yet
as standardized and scientifically robust as the cases of the ecological, carbon, and
water footprints (Galli et al. 2012); therefore, there is much room for improvement
in future studies of the energy footprint.