DESIGNING TERRITORIAL METABOLISM

42 ON TERRITORIAL METABOLISM
INTRODUCTION
City administrations from Beijing, Amsterdam, Paris, and Brussels have in common
that they claim to use the principles of “circular economy” as their compass for
navigating through economic and environmental challenges. The policy roadmaps
they produce in this context often describe the circularization of urban systems in
terms of their “metabolism.” The two central concepts underpinning these policies—the
urban “metabolism” and its “circularization”—are, however, often very
poorly characterized.
Regarding the notion of “metabolism,” the metabolic overviews that have been
commissioned by metropolises are largely confined to discussing flows to, from,
and within a given urban agglomeration (Ecores et al., 2015). In most cases, this is
achieved through quantitative accounts in the form of Material and Energy Flow
Analysis (MEFA) or Sankey diagrams. The intensity of flows is, however, not the only
dimension of a city’s metabolism. The first objective of this article is to discuss the
implications of two other dimensions of urban metabolism: the spatial structure in
which these flows are organized and the socio-technical agents that govern them.
However, current uses of the notion of “circularization” are also questionable.
Arnsperger and Bourg (2017) recently pointed out that many of the policies and
promises churned out by governments, consultancies, and corporations are, in fact,
not “authentically” circular. Although they are steeped in the language and ideology
of economic growth, these circular economy initiatives may eventually fall short of
expectations. As an extension to the critical stance of Arnsperger and Bourg, our
second objective is to ask about the theoretical implications of circularization for
the intensity, spatial structure, and socio-technical agents of urban metabolism.
A better understanding of the different dimensions of urban metabolism and
their circularization is not only of theoretical interest; we argue that issues of intensity,
spatial structure, and socio-technical agents are also relevant in the practical
context of making plans and strategies aimed at improving metabolic flows in the
urban landscape. To be sure, previous research on planning for circular economy,
and in particular contributions based on research by design (Grulois et al., 2015),
have already touched upon all three of the dimensions of urban metabolism that
we highlight in this paper. However, a critical approach that frontally and explicitly
addresses the multidimensional character of (circular) urban metabolism is still
lacking in the literature. The concluding section will return to the practical relevance
of the theoretical considerations developed in this paper by assessing their implications
for planning and design.
INTENSITY
The intensity of stocks and flows of water, construction materials, nitrogen,
food, fuel, final products, municipal waste, etc. is arguably the most explored aspect
of urban metabolism in industrial ecology and neighboring fields (Weisz and Steinberger,
2010). The analysis of metabolic intensity relies on quantitative indicators
such as the primary and final consumption within a given territory. The literature has
also developed tools that bring several quantitative indicators of metabolic intensity
together, such as Material and Energy Flow Analysis (MEFA), Life Cycle Analysis
(LFA), or Sankey diagrams. These approaches have the merit of allowing more
systemic analyses of the relationships between different flows (Haberl et al., 2004).
Following quantitative indicators over time has led to the observation that the flows
of many substances have intensified in most cities over the XIX th and XX th centuries
(Barles, 2015; McNeill, 2001).