94
6 Benchmarking the Carbon, Water and Land Footprints …
As one of the most widespread systems of threshold indicators, planetary boundaries present, for the first time, an up-to-date comprehensive estimate of critical
values for nine Earth-system processes at the global scale. A threshold-behavioral
distinction has been made between “systemic processes” with explicit global thresholds, such as climate change, and “aggregated processes” without strong evidence of
planetary-scale thresholds, such as water use and land use (Rockström et al. 2009).
For systemic processes, in theory, their planetary boundaries can be readily allocated to nations and regions through a top-down approach. The reality is, however,
that the control variables used for all three systemic planetary boundaries (climate
change, ocean acidification, and stratospheric ozone depletion) are concentrations or
intensity indices (such as 2 °C) that do not allow for yielding remaining budgets and
for dividing into country-specific shares. To overcome this issue, all such threshold
values must be translated into quantities of flow characters, such as Gt/yr of CO 2 .
Things get more complicated when it comes to aggregated processes, for which
no top-down approach is applicable, because a truly global threshold behavior hardly
exists unless boundaries at a local or regional level have been repeatedly transgressed
for large parts of the world (Lewis 2012; Rockström et al. 2009). More specifically,
the environmental boundaries for water and land use are essentially subject to the
local availability and scarcity of freshwater and land and thus vary over space, while
the planetary carbon boundary potentially can be applied to any specific regions,
regardless of location. All this points to a key methodological limitation of the present
PBF: it is inherently incapable of downscaling environmental boundaries from the
planetary level to smaller levels because of the inappropriate control variables and
the omission of sub-global dynamics that are critical to both regional and global
sustainability.
6.1.4 The Need for Integrating Footprints and Boundaries
into ESA
In summary, environmental footprints and planetary boundaries fall into the categories of descriptive pressure indicators and critical threshold indicators, respectively.
Biophysical elements underlying the two have the potential to constitute an evolving
representation of ESA, where a distinction between “sustainable” and “unsustainable” activities is made by showing to what extent a planetary or regional environmental boundary has been approached or exceeded by the corresponding footprint
(Fang et al. 2014). This is accompanied by the recognition that planetary boundaries
for both systemic and aggregated processes are necessary to allocate to a national or
regional level in support of decision-making (Fang et al. 2015).
In this chapter, we first introduce an integrated framework that makes complementary use of environmental footprints and planetary boundaries originating from two
isolated research fields. We then apply this framework to a comparative analysis of
national-scale environmental sustainability by measuring and integrating three pairs
6 Benchmarking the Carbon, Water and Land Footprints …
As one of the most widespread systems of threshold indicators, planetary boundaries present, for the first time, an up-to-date comprehensive estimate of critical
values for nine Earth-system processes at the global scale. A threshold-behavioral
distinction has been made between “systemic processes” with explicit global thresholds, such as climate change, and “aggregated processes” without strong evidence of
planetary-scale thresholds, such as water use and land use (Rockström et al. 2009).
For systemic processes, in theory, their planetary boundaries can be readily allocated to nations and regions through a top-down approach. The reality is, however,
that the control variables used for all three systemic planetary boundaries (climate
change, ocean acidification, and stratospheric ozone depletion) are concentrations or
intensity indices (such as 2 °C) that do not allow for yielding remaining budgets and
for dividing into country-specific shares. To overcome this issue, all such threshold
values must be translated into quantities of flow characters, such as Gt/yr of CO 2 .
Things get more complicated when it comes to aggregated processes, for which
no top-down approach is applicable, because a truly global threshold behavior hardly
exists unless boundaries at a local or regional level have been repeatedly transgressed
for large parts of the world (Lewis 2012; Rockström et al. 2009). More specifically,
the environmental boundaries for water and land use are essentially subject to the
local availability and scarcity of freshwater and land and thus vary over space, while
the planetary carbon boundary potentially can be applied to any specific regions,
regardless of location. All this points to a key methodological limitation of the present
PBF: it is inherently incapable of downscaling environmental boundaries from the
planetary level to smaller levels because of the inappropriate control variables and
the omission of sub-global dynamics that are critical to both regional and global
sustainability.
6.1.4 The Need for Integrating Footprints and Boundaries
into ESA
In summary, environmental footprints and planetary boundaries fall into the categories of descriptive pressure indicators and critical threshold indicators, respectively.
Biophysical elements underlying the two have the potential to constitute an evolving
representation of ESA, where a distinction between “sustainable” and “unsustainable” activities is made by showing to what extent a planetary or regional environmental boundary has been approached or exceeded by the corresponding footprint
(Fang et al. 2014). This is accompanied by the recognition that planetary boundaries
for both systemic and aggregated processes are necessary to allocate to a national or
regional level in support of decision-making (Fang et al. 2015).
In this chapter, we first introduce an integrated framework that makes complementary use of environmental footprints and planetary boundaries originating from two
isolated research fields. We then apply this framework to a comparative analysis of
national-scale environmental sustainability by measuring and integrating three pairs