356
13.2.3.2 Absolute vs. Relative
The second dimension we use for defining metrics is absolute vs. relative. Absolute
metrics have units of some sort (cubic meters, kilowatt-hours, etc.), whereas relative metrics are dimensionless, essentially a rephrasing of absolute metrics relative
to some normalization factor.
At the establishment level, absolute metrics can be converted to a relative metric
by scaling to an industry standard (e.g., best practice) or a target performance metric
(e.g., Carnot efficiency). For example, the Corporate Average Fuel Economy fuel
efficiency and emissions standards for company-wide vehicle sales determine
whether a company’s vehicles produce emissions at levels below that of the target
standard as well as its competitors.
Box 13.2 Boundaries Are Not Always Political
We are often used to thinking of “boundaries” in terms of political boundaries
between countries or between other governmental jurisdictions (e.g., counties, states). However, within the environmental sustainability literature, there
is a concept of ‘planetary boundaries,’ or sustainable limits defined by scientific research and translated via government or industry policy (Rockström, J.,
et al. 2009, Heijungs et al. 2014). Ordinarily, LCA studies produce intensive
characterizations of products or services that do not address whether the product or service fits within sustainable consumption patterns. The imposition of
these so-called planetary boundaries enables the determination of a sustainable pattern of consumption for the products and services under analysis.
The term “planetary” is also somewhat misleading since in some cases the
spatial region would be more restrictive, depending on the impact being analyzed. This is most clearly demonstrated in the case of water management,
where the spatial region of interest would be the extent of the watershed where
the processes and activities.
Limits are most appropriately defined at the meso/macro scale as an absolute
metric (e.g., water supply, availability, or precipitation within the watershed). One
way to achieve the imposition of the limit is using the distance-to-target approach,
by which the weighting factor of the impact is scaled as one approaches the limit.
For example, to determine stress on a resource, we can scale by a factor f:
f
D
A
=
(13.2)
where A and D are availability and demand, respectively, of food, water, energy, or
another resource of interest (Boulay et al. 2015).
An example water stress indicator is the amount of water available in a region
(e.g., water in a basin as typical rainfall, flow rates, etc.) relative to water demand
M. Carbajales-Dale and C. W. King
13.2.3.2 Absolute vs. Relative
The second dimension we use for defining metrics is absolute vs. relative. Absolute
metrics have units of some sort (cubic meters, kilowatt-hours, etc.), whereas relative metrics are dimensionless, essentially a rephrasing of absolute metrics relative
to some normalization factor.
At the establishment level, absolute metrics can be converted to a relative metric
by scaling to an industry standard (e.g., best practice) or a target performance metric
(e.g., Carnot efficiency). For example, the Corporate Average Fuel Economy fuel
efficiency and emissions standards for company-wide vehicle sales determine
whether a company’s vehicles produce emissions at levels below that of the target
standard as well as its competitors.
Box 13.2 Boundaries Are Not Always Political
We are often used to thinking of “boundaries” in terms of political boundaries
between countries or between other governmental jurisdictions (e.g., counties, states). However, within the environmental sustainability literature, there
is a concept of ‘planetary boundaries,’ or sustainable limits defined by scientific research and translated via government or industry policy (Rockström, J.,
et al. 2009, Heijungs et al. 2014). Ordinarily, LCA studies produce intensive
characterizations of products or services that do not address whether the product or service fits within sustainable consumption patterns. The imposition of
these so-called planetary boundaries enables the determination of a sustainable pattern of consumption for the products and services under analysis.
The term “planetary” is also somewhat misleading since in some cases the
spatial region would be more restrictive, depending on the impact being analyzed. This is most clearly demonstrated in the case of water management,
where the spatial region of interest would be the extent of the watershed where
the processes and activities.
Limits are most appropriately defined at the meso/macro scale as an absolute
metric (e.g., water supply, availability, or precipitation within the watershed). One
way to achieve the imposition of the limit is using the distance-to-target approach,
by which the weighting factor of the impact is scaled as one approaches the limit.
For example, to determine stress on a resource, we can scale by a factor f:
f
D
A
=
(13.2)
where A and D are availability and demand, respectively, of food, water, energy, or
another resource of interest (Boulay et al. 2015).
An example water stress indicator is the amount of water available in a region
(e.g., water in a basin as typical rainfall, flow rates, etc.) relative to water demand
M. Carbajales-Dale and C. W. King