5.5 Research Agenda for Strengthening the Footprint–boundary …
81
As such, aggregated issues are unlikely to show strong evidence of global threshold
behaviors (Rockström et al. 2009b); unless their heterogeneous impacts on local environment have been extensively replicated and ultimately spread worldwide (Lewis
2012). Consequently, setting planetary boundaries merely and waiting until we
approach them are dangerous and may significantly obscure the seriousness of environmental degradation at a regional or local scale. For example, while the planetary
boundary for phosphorus has not yet been transgressed (Rockström et al. 2009a,
b), a striking fact which should not be neglected is that the absorptive capacity for
phosphorus in two-thirds of the world’s river basins has already been fully consumed
(Hoekstra and Wiedmann 2014).
This justifies the importance of developing measurable aggregated boundaries
regionally or locally, which however remains largely unexplored in current PBF. As
discussed, the biocapacity and water availability provide paradigms for the measurement of local and regional environmental boundaries. We argue that aggregating
local or regional boundaries to the national level would allow for a reasonably
refined estimate of national boundaries for those aggregated issues. This could be
achieved by means of a bottom-up approach. The sensitivity to place of aggregated
issues, however, constitutes a major constraint on applications of such an upscaling
(Nykvist et al. 2013). Another challenge concerns the allocation problem (Heijungs
and Frischknecht 1998), as the real geographical scale of anthropogenic perturbation
and associated impacts, which for instance can be a river basin, is very likely to go
beyond national borders.
5.5.2 Partitioning of Systemic Planetary Boundaries
for Sub-Global Assessments
On the other hand, it is also unclear how long the boundary exceedance actually takes
to cause catastrophic environmental effects, even though a global threshold effect for
systemic issues (climate change, ozone depletion, and ocean acidification) arguably
exists regardless of where stressors are imposed (Nykvist et al. 2013; Rockström
et al. 2009b). Such a transition is elusive and unpredictable, typically lagged by
centuries, millennia, or even millions of years (Hughes et al. 2013), as evidenced
in the observation that over the past two billion years global transitions rarely took
place, with an estimate of five times merely (Barnosky et al. 2012). This is why
the planetary boundaries practitioners recently concede that exceeding one or few
planetary boundaries is unlikely to give rise to disastrous consequences as immediate
as previously thought (Hughes et al. 2013; Lenton and Williams 2013).
Misinterpretation may occur if one misunderstands the precautionary principle
that the planetary boundaries concept relies on and equates a surpassed boundary
with a critical transition that corresponds to regime shift—a sharp and persistent
reorganization of the state of an ecosystem, which can hardly be anticipated and
reversed by man (Brook et al. 2013). Besides, the global nature of systemic issues
81
As such, aggregated issues are unlikely to show strong evidence of global threshold
behaviors (Rockström et al. 2009b); unless their heterogeneous impacts on local environment have been extensively replicated and ultimately spread worldwide (Lewis
2012). Consequently, setting planetary boundaries merely and waiting until we
approach them are dangerous and may significantly obscure the seriousness of environmental degradation at a regional or local scale. For example, while the planetary
boundary for phosphorus has not yet been transgressed (Rockström et al. 2009a,
b), a striking fact which should not be neglected is that the absorptive capacity for
phosphorus in two-thirds of the world’s river basins has already been fully consumed
(Hoekstra and Wiedmann 2014).
This justifies the importance of developing measurable aggregated boundaries
regionally or locally, which however remains largely unexplored in current PBF. As
discussed, the biocapacity and water availability provide paradigms for the measurement of local and regional environmental boundaries. We argue that aggregating
local or regional boundaries to the national level would allow for a reasonably
refined estimate of national boundaries for those aggregated issues. This could be
achieved by means of a bottom-up approach. The sensitivity to place of aggregated
issues, however, constitutes a major constraint on applications of such an upscaling
(Nykvist et al. 2013). Another challenge concerns the allocation problem (Heijungs
and Frischknecht 1998), as the real geographical scale of anthropogenic perturbation
and associated impacts, which for instance can be a river basin, is very likely to go
beyond national borders.
5.5.2 Partitioning of Systemic Planetary Boundaries
for Sub-Global Assessments
On the other hand, it is also unclear how long the boundary exceedance actually takes
to cause catastrophic environmental effects, even though a global threshold effect for
systemic issues (climate change, ozone depletion, and ocean acidification) arguably
exists regardless of where stressors are imposed (Nykvist et al. 2013; Rockström
et al. 2009b). Such a transition is elusive and unpredictable, typically lagged by
centuries, millennia, or even millions of years (Hughes et al. 2013), as evidenced
in the observation that over the past two billion years global transitions rarely took
place, with an estimate of five times merely (Barnosky et al. 2012). This is why
the planetary boundaries practitioners recently concede that exceeding one or few
planetary boundaries is unlikely to give rise to disastrous consequences as immediate
as previously thought (Hughes et al. 2013; Lenton and Williams 2013).
Misinterpretation may occur if one misunderstands the precautionary principle
that the planetary boundaries concept relies on and equates a surpassed boundary
with a critical transition that corresponds to regime shift—a sharp and persistent
reorganization of the state of an ecosystem, which can hardly be anticipated and
reversed by man (Brook et al. 2013). Besides, the global nature of systemic issues