27
likely future outcome. This dogma, however, contradicts our intuition and the way
the term scenario is often used. Especially when it covers only a short time span into
the future, a scenario for the future development of SEM can appear to have
predictive character (Börjeson et al. 2006 ). We assert that the apparent short-term
determinacy of the indeterminate socio-metabolic system is a result of the slow
turnover of in-use stocks, such as buildings, infrastructure, and products of different
kinds, which adds considerable inertia to the system. The large amount of social and
biophysical resources required to transform in-use stocks limits the speed at which
the system can deviate from its present state (Pauliuk and Müller 2014 ). Hence, the
spectrum of likely future states of SEM is the narrower the shorter the time horizon.
Still, this predictability of an indeterminate system differs from the “absolute” predictions for truly deterministic systems because in indeterminate systems, unforeseen events such as the discovery of new technologies, sudden political changes, or
natural catastrophes can substantially alter the trajectory even in the short run. To
accommodate for the indeterminacy of SEM in the near future, prospective shortterm models of society’s metabolism are complemented by risk assessment .
The coming transformation of society’s metabolism will require us to rebuild a
substantial fraction of society’s in-use stocks. The more complete the transformation, the less the future state of SEM is determined by present in-use stocks.
Scenarios that cover time scales during which the coming transition may take place
are therefore only little constrained by the inertia given by present stocks.
Consequently, these scenarios have no predictive but explorative (What can happen?) or normative (How can a specifi c target be reached?) character (Börjeson
et al. 2006 ). Prospective models in industrial ecology are used to study the transition
ahead, and hence, the scenarios they generate are explorative or normative but not
predictive.
3 Prospective Modeling in Industrial Ecology: State
of the Art
3.1 Prospective Modeling with Established IE Methods
Industrial ecology methods and models, which allow us to study complex industrial
systems, have been at the forefront of the interdisciplinary systems approach for
more than three decades. Traditional industrial ecology methods include EE-I/O,
LCA, MFA , urban metabolism , and industrial symbiosis. They cover a wide spectrum of spatial, temporal, and organizational scales, from static snapshots of the
supply chain of local companies to studies of the evolution of aggregated material
and energy fl ow accounts through the last centuries. They offer to decision-makers
quantitative information about supply chains, environmental impacts embodied in
trade, material and energy stocks and fl ows, and options for system-wide
improvement.
2 Prospective Models of Society’s Future Metabolism: What Industrial Ecology Has…
likely future outcome. This dogma, however, contradicts our intuition and the way
the term scenario is often used. Especially when it covers only a short time span into
the future, a scenario for the future development of SEM can appear to have
predictive character (Börjeson et al. 2006 ). We assert that the apparent short-term
determinacy of the indeterminate socio-metabolic system is a result of the slow
turnover of in-use stocks, such as buildings, infrastructure, and products of different
kinds, which adds considerable inertia to the system. The large amount of social and
biophysical resources required to transform in-use stocks limits the speed at which
the system can deviate from its present state (Pauliuk and Müller 2014 ). Hence, the
spectrum of likely future states of SEM is the narrower the shorter the time horizon.
Still, this predictability of an indeterminate system differs from the “absolute” predictions for truly deterministic systems because in indeterminate systems, unforeseen events such as the discovery of new technologies, sudden political changes, or
natural catastrophes can substantially alter the trajectory even in the short run. To
accommodate for the indeterminacy of SEM in the near future, prospective shortterm models of society’s metabolism are complemented by risk assessment .
The coming transformation of society’s metabolism will require us to rebuild a
substantial fraction of society’s in-use stocks. The more complete the transformation, the less the future state of SEM is determined by present in-use stocks.
Scenarios that cover time scales during which the coming transition may take place
are therefore only little constrained by the inertia given by present stocks.
Consequently, these scenarios have no predictive but explorative (What can happen?) or normative (How can a specifi c target be reached?) character (Börjeson
et al. 2006 ). Prospective models in industrial ecology are used to study the transition
ahead, and hence, the scenarios they generate are explorative or normative but not
predictive.
3 Prospective Modeling in Industrial Ecology: State
of the Art
3.1 Prospective Modeling with Established IE Methods
Industrial ecology methods and models, which allow us to study complex industrial
systems, have been at the forefront of the interdisciplinary systems approach for
more than three decades. Traditional industrial ecology methods include EE-I/O,
LCA, MFA , urban metabolism , and industrial symbiosis. They cover a wide spectrum of spatial, temporal, and organizational scales, from static snapshots of the
supply chain of local companies to studies of the evolution of aggregated material
and energy fl ow accounts through the last centuries. They offer to decision-makers
quantitative information about supply chains, environmental impacts embodied in
trade, material and energy stocks and fl ows, and options for system-wide
improvement.
2 Prospective Models of Society’s Future Metabolism: What Industrial Ecology Has…