6.1 Introduction
93
6.1.2 Environmental Footprints: Descriptive Pressure
Indicators
To represent how much pressure or impact humanity exerts on the Earth’s ecosystems,
an expanding list of environmental footprints has been introduced to the scientific
community over recent years ( ˇ
Cuˇ cek et al. 2012; Hoekstra and Wiedmann 2014).
Irrespective of the prevalence of footprint-style indicators, there remains a considerable amount of confusion and controversy regarding the concepts and methodologies
(Giampietro and Saltelli 2014; Kitzes et al. 2009; Van den Bergh and Grazi 2014).
A consequence is that there is, to our knowledge, not yet an explicit and agreed definition of footprints. To bring transparency to this issue, here we propose a general
definition as follows: environmental footprints are tools that communicate humandriven pressure on the environment and associated impacts. To our understanding,
this is probably the common ground on which most, if not all, footprint indicators
depend crucially.
The ecological footprint (Rees 1992), the water footprint (Hoekstra and Hung
2002), and the carbon footprint (Wiedmann and Minx 2008) have been subject to
a wide range of scientific scrutiny. A striking overlap has been identified between
the ecological and carbon footprints in terms of fossil carbon emissions. To avoid
double-counting, it is suggested to exclude the energy component from the ecological
footprint accounting and to refer to the remainder as “land footprint” which accounts
for the pressure associated with actual land use (Fang et al. 2014; O’Brien et al. 2015).
Collectively, the carbon, water, and land footprints are able to capture the complicated
effects of human activities, including carbon emissions (climate change), water use,
and land use, on the Earth’s system processes.
6.1.3 Planetary Boundaries: Critical Threshold Indicators
The planetary boundaries framework (PBF) offers a set of quantitative capacity
thresholds for vital Earth system processes based on recent scientific evidence
(Rockström et al. 2009). Even though planetary boundaries were not designed to
downscale to smaller scales (Steffen et al. 2015), there is an increasing demand for
allocation to national and regional levels at which numerous environmental policies are formulated and executed with broad participation of stakeholders. This has
triggered a growing interest in the development of approaches to detecting sustainability limits and to anticipating critical transitions at multiple scales (Cole et al.
2014; Dearing et al. 2014; Smith et al. 2014). Furthermore, based on recent understanding of the complexity of the Earth system functioning and resilience, Steffen
et al. (2015) have implemented updates of planetary boundaries, with a special focus
on those that are spatially heterogeneous and show threshold behaviors at sub-global
scales.
93
6.1.2 Environmental Footprints: Descriptive Pressure
Indicators
To represent how much pressure or impact humanity exerts on the Earth’s ecosystems,
an expanding list of environmental footprints has been introduced to the scientific
community over recent years ( ˇ
Cuˇ cek et al. 2012; Hoekstra and Wiedmann 2014).
Irrespective of the prevalence of footprint-style indicators, there remains a considerable amount of confusion and controversy regarding the concepts and methodologies
(Giampietro and Saltelli 2014; Kitzes et al. 2009; Van den Bergh and Grazi 2014).
A consequence is that there is, to our knowledge, not yet an explicit and agreed definition of footprints. To bring transparency to this issue, here we propose a general
definition as follows: environmental footprints are tools that communicate humandriven pressure on the environment and associated impacts. To our understanding,
this is probably the common ground on which most, if not all, footprint indicators
depend crucially.
The ecological footprint (Rees 1992), the water footprint (Hoekstra and Hung
2002), and the carbon footprint (Wiedmann and Minx 2008) have been subject to
a wide range of scientific scrutiny. A striking overlap has been identified between
the ecological and carbon footprints in terms of fossil carbon emissions. To avoid
double-counting, it is suggested to exclude the energy component from the ecological
footprint accounting and to refer to the remainder as “land footprint” which accounts
for the pressure associated with actual land use (Fang et al. 2014; O’Brien et al. 2015).
Collectively, the carbon, water, and land footprints are able to capture the complicated
effects of human activities, including carbon emissions (climate change), water use,
and land use, on the Earth’s system processes.
6.1.3 Planetary Boundaries: Critical Threshold Indicators
The planetary boundaries framework (PBF) offers a set of quantitative capacity
thresholds for vital Earth system processes based on recent scientific evidence
(Rockström et al. 2009). Even though planetary boundaries were not designed to
downscale to smaller scales (Steffen et al. 2015), there is an increasing demand for
allocation to national and regional levels at which numerous environmental policies are formulated and executed with broad participation of stakeholders. This has
triggered a growing interest in the development of approaches to detecting sustainability limits and to anticipating critical transitions at multiple scales (Cole et al.
2014; Dearing et al. 2014; Smith et al. 2014). Furthermore, based on recent understanding of the complexity of the Earth system functioning and resilience, Steffen
et al. (2015) have implemented updates of planetary boundaries, with a special focus
on those that are spatially heterogeneous and show threshold behaviors at sub-global
scales.