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the treatment, pumping and heating of the water, and, effectively, we consume the
energy and material simultaneously whether it is in a hot shower or a hot cup of
coffee. Similarly, the energy use and emissions associated with industry are linked
to the movement and transformation of materials: energy may be used in a factory
but the output is the material product.
It has been noted already that there is more embodied energy in household consumption of goods and services than directly consumed energy (Lenzen et al. 2004 ).
Furthermore, as housing standards improve and operational energy use declines,
there is an increasing importance of embedded emissions in the materials of dwelling construction (Giesekam et al. 2014 ).
Lastly, and relevant to the next section, materials exhibit dynamic path dependency. Material fl ows enter and stay in the system as stocks and leave, or are recycled, at a future date. Most energy embedded in products is not recoverable, but an
interesting and useful feature of material stocks in-use is their latent ability to contribute to material and energy saving through recycling in the future.
2.3 The Importance of Representing Stocks
Operational effi ciency and embodied energy are not simply properties of the aggregated material stock but of individual items making up infrastructure and other artefacts (appliances, durable goods, etc.). These stocks contain a great deal of material,
but they also have discrete lifetimes and often interact across sectors to supply services to society. This key point has been made by Fischer-Kowalski and Weisz
( 1999 ): ‘physical infrastructure (buildings, machines, artefacts in-use and livestock)’ is ‘core to our understanding of the society-nature interrelation.’ In-use
stocks represent large monetary investments and determine the long-term dynamics
of social metabolism. Through their long lifetime in-use, they are responsible for
lock-ins of lifestyles and emission pathways.
Urban in-use stocks also relate to the density and accessibility of urban spaces
and the capacity and utility of urban systems such as public transport or water supply systems. A study of global cities over 10 years (Angel et al. 2010 ) revealed that
recent trends are away from denser cities, and the implications in both the
industrialised and developing world are for cities to take up yet more space and for
more infrastructure to be needed to fi ll and connect that space.
Stocks and fl ows play different roles over different time scales. Over the shortterm (less than 5 years), physical and economic fl ows can change with the vicissitudes of markets, income ( GDP ), prices and events. Over the long-term, deeper
structural changes related to population dynamics, urbanisation and infrastructure
development, long-run economic policy, cumulative savings, resource depletion and
institutional arrangements are more connected to the development of stocks. Thus,
long-term change is recorded in the quantity and quality of in-use stocks, and existing stocks and systems of stocks infl uence the long-term future. This is valid from
both the metabolic and the wealth and income perspectives (Piketty 2013 ).
6 A Socio-economic Metabolism Approach to Sustainable Development and Climate…
the treatment, pumping and heating of the water, and, effectively, we consume the
energy and material simultaneously whether it is in a hot shower or a hot cup of
coffee. Similarly, the energy use and emissions associated with industry are linked
to the movement and transformation of materials: energy may be used in a factory
but the output is the material product.
It has been noted already that there is more embodied energy in household consumption of goods and services than directly consumed energy (Lenzen et al. 2004 ).
Furthermore, as housing standards improve and operational energy use declines,
there is an increasing importance of embedded emissions in the materials of dwelling construction (Giesekam et al. 2014 ).
Lastly, and relevant to the next section, materials exhibit dynamic path dependency. Material fl ows enter and stay in the system as stocks and leave, or are recycled, at a future date. Most energy embedded in products is not recoverable, but an
interesting and useful feature of material stocks in-use is their latent ability to contribute to material and energy saving through recycling in the future.
2.3 The Importance of Representing Stocks
Operational effi ciency and embodied energy are not simply properties of the aggregated material stock but of individual items making up infrastructure and other artefacts (appliances, durable goods, etc.). These stocks contain a great deal of material,
but they also have discrete lifetimes and often interact across sectors to supply services to society. This key point has been made by Fischer-Kowalski and Weisz
( 1999 ): ‘physical infrastructure (buildings, machines, artefacts in-use and livestock)’ is ‘core to our understanding of the society-nature interrelation.’ In-use
stocks represent large monetary investments and determine the long-term dynamics
of social metabolism. Through their long lifetime in-use, they are responsible for
lock-ins of lifestyles and emission pathways.
Urban in-use stocks also relate to the density and accessibility of urban spaces
and the capacity and utility of urban systems such as public transport or water supply systems. A study of global cities over 10 years (Angel et al. 2010 ) revealed that
recent trends are away from denser cities, and the implications in both the
industrialised and developing world are for cities to take up yet more space and for
more infrastructure to be needed to fi ll and connect that space.
Stocks and fl ows play different roles over different time scales. Over the shortterm (less than 5 years), physical and economic fl ows can change with the vicissitudes of markets, income ( GDP ), prices and events. Over the long-term, deeper
structural changes related to population dynamics, urbanisation and infrastructure
development, long-run economic policy, cumulative savings, resource depletion and
institutional arrangements are more connected to the development of stocks. Thus,
long-term change is recorded in the quantity and quality of in-use stocks, and existing stocks and systems of stocks infl uence the long-term future. This is valid from
both the metabolic and the wealth and income perspectives (Piketty 2013 ).
6 A Socio-economic Metabolism Approach to Sustainable Development and Climate…