7.1 Conclusions
117
contexts as well. Besides, it offers experts without life cycle assessment (LCA)expertise new insights into how to form a truly integrated footprint family—which
remains unsolved and steeped in controversy (see Chap. 4).
There is no doubt that footprint practitioners and users have learned and borrowed
much from the LCA community. The strengths of LCA in assessing environmental
impacts could allow many footprint topics (e.g. climate change, resource use) to
be addressed under an LCA framework, in particular those that can be measured
in relation to a functional unit. The carbon and abiotic resource footprints are two
obvious examples of LCA-based footprints, where a variety of human disturbance
is tabulated and translated into the inventory of greenhouse gas (GHG) emissions
and abiotic resource extractions and further modeled quantitatively and expressed as
impact scores according to their relative contributions to climate change and resource
depletion, respectively (see Chap. 4). Given the satisfactory performance of life cycle
approaches on scientific robustness, environmental relevance and reproducibility,
taking advantage of LCA has now been a fashion trend followed by a growing group
of footprint users.
Regardless of the ubiquity of life cycle approaches to footprinting, like any
methodologies, however, LCA has its own limitations and uncertainties. Narrowing
environmental footprints down to an LCA context potentially creates blind spots,
where exhaustive inventory data for compiling or consensus models for characterization of impact pathways are unavailable. Moreover, some of the environmental
footprints such as the classical ecological and water footprints are designed in a way
that permits a measure of pressures, not impacts, of anthropogenic activities on the
planet’s environment, with the belief that this valuable information may get lost if
translating into an impact score through characterization modeling. In addition, there
are certain important types of questions for which a footprint-type representation
would be preferable to a life cycle-type representation, as is the case for organization
environmental footprint (OEF). For these reasons, LCA should not be interpreted as a
necessity, but rather an option, for defining and computing environmental footprints
(see Chap. 4).
While focusing on the measurement of planetary boundaries for several environmental issues, the ultimate aim of the planetary boundaries framework (PBF)
is to identify the remaining safe operating space for humans by comparing planetary boundaries with current environmental states. The sole use of expert knowledge
and lack of quantitative methods, however, compromise the reliability of current
estimate—a neglected part of the PBF which could have been more rigorous and
accurate if appropriate footprint models are employed instead. On the contrary, the
lack of comparison to threshold indicators makes many of the environmental footprints (e.g. nitrogen footprint, biodiversity footprint) policy-irrelevant. Even for those
which have already been linked to threshold values, the threshold estimates are far
from satisfactory and much work remains to be done. As a result, it becomes clear
that recent developments regarding planetary boundaries could facilitate the ongoing
process of benchmarking environmental footprints against the corresponding critical
thresholds.
117
contexts as well. Besides, it offers experts without life cycle assessment (LCA)expertise new insights into how to form a truly integrated footprint family—which
remains unsolved and steeped in controversy (see Chap. 4).
There is no doubt that footprint practitioners and users have learned and borrowed
much from the LCA community. The strengths of LCA in assessing environmental
impacts could allow many footprint topics (e.g. climate change, resource use) to
be addressed under an LCA framework, in particular those that can be measured
in relation to a functional unit. The carbon and abiotic resource footprints are two
obvious examples of LCA-based footprints, where a variety of human disturbance
is tabulated and translated into the inventory of greenhouse gas (GHG) emissions
and abiotic resource extractions and further modeled quantitatively and expressed as
impact scores according to their relative contributions to climate change and resource
depletion, respectively (see Chap. 4). Given the satisfactory performance of life cycle
approaches on scientific robustness, environmental relevance and reproducibility,
taking advantage of LCA has now been a fashion trend followed by a growing group
of footprint users.
Regardless of the ubiquity of life cycle approaches to footprinting, like any
methodologies, however, LCA has its own limitations and uncertainties. Narrowing
environmental footprints down to an LCA context potentially creates blind spots,
where exhaustive inventory data for compiling or consensus models for characterization of impact pathways are unavailable. Moreover, some of the environmental
footprints such as the classical ecological and water footprints are designed in a way
that permits a measure of pressures, not impacts, of anthropogenic activities on the
planet’s environment, with the belief that this valuable information may get lost if
translating into an impact score through characterization modeling. In addition, there
are certain important types of questions for which a footprint-type representation
would be preferable to a life cycle-type representation, as is the case for organization
environmental footprint (OEF). For these reasons, LCA should not be interpreted as a
necessity, but rather an option, for defining and computing environmental footprints
(see Chap. 4).
While focusing on the measurement of planetary boundaries for several environmental issues, the ultimate aim of the planetary boundaries framework (PBF)
is to identify the remaining safe operating space for humans by comparing planetary boundaries with current environmental states. The sole use of expert knowledge
and lack of quantitative methods, however, compromise the reliability of current
estimate—a neglected part of the PBF which could have been more rigorous and
accurate if appropriate footprint models are employed instead. On the contrary, the
lack of comparison to threshold indicators makes many of the environmental footprints (e.g. nitrogen footprint, biodiversity footprint) policy-irrelevant. Even for those
which have already been linked to threshold values, the threshold estimates are far
from satisfactory and much work remains to be done. As a result, it becomes clear
that recent developments regarding planetary boundaries could facilitate the ongoing
process of benchmarking environmental footprints against the corresponding critical
thresholds.