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60 ON TERRITORIAL METABOLISM “nature” into the city. 4 As a result, under the pressure of modernist urban development, the built and open spaces—or more simply, city and “nature”—were separated again. Discourse and practice within urbanism narrowed the focus of these concepts to the protection of historical neighborhoods. Research and practice in regional geography and urban ecology disappeared in favor of social geography and human ecology that focused on urban social conflicts (Grulois, 2015). At the same time, despite the comprehensive attention that the Brussels school paid to urban metabolism, additional remarkable works on the metabolism of Brussels influenced industrial ecology and the study of energy and material flows (Erkman, 2004), thus narrowing the scope of these investigations to urban space and environment. As an example, the collective work L’Ecosystéme Belgique, Essai d’écologie industrielle (Billen et al., 1983) extended the ecosystem study approach to the whole national industrial system by collecting data on material and energy input and output on the national scale of Belgium. The study questioned the efficiency of material circulation in six main production chains (iron, glass, plastic, lead, wood, and food), and the results showed the predominant linearity and sectorialization of industrial production, implicitly arguing that a more integrated policy was needed. Even though one of the co-authors, Gilles Billen, was a former student of Duvigneaud, outputs were not spatialized on a geographical scale and thus not related to natural ecosystem but rather illustrated through abstract schemes of material and energy flows. The spatial connotation of metabolism was no longer in the picture. THE RESURGENCE OF URBAN METABOLISM DISCOURSE IN BRUSSELS: CURRENT PERSPECTIVES AND DILEMMAS Recently, there has been a strong return to the debate on urban metabolism in Brussels. In 2012, the Etopia think tank of the Belgian green political party—Ecolo— organized a symposium on the subject in which Suren Erkman was invited to participate in a discussion with former Duvigneaud students (Etopia, 2012). 5 Following the symposium, Ecolo supported a first study on the application of the concept of urban metabolism—and industrial ecology—to support sustainable development of the Brussels Region (Calay, 2013). Although the work of Duvigneaud stands as a historical point of reference, the study examines more recent accounting methods such as the Eurostat method, the Baccini method, and the Climatecon method (Calay, 2013). Since the 1990s, those methods had been applied in various ways to European cities such as Geneva (Faist Emmengger, 2003) and Paris (Barles, 2007). Following these trends, regional programs and policies of the 2010s have fully embraced the urban metabolism discourse as a tool to boost local economic and social development and to meet regional environmental targets. The Sustainable Regional Development Plan project (PRDD, 2014) integrates the issue and deploys the term “urban metabolism” when addressing environmental and resource efficiency issues within a regional perspective (PRDD, 2014: 14). Similarly, the term “ecology” is explicitly used, albeit to refer specifically to “industrial ecology” (PRDD, 2014: 156) in addressing strategies of economic development through principles such as clustering productive zones. In the PRDD project, apart from the use of these two terms, there is no specification concerning what is meant by ecology or about the terms into which urbanism should actually integrate an ecological perspective. The ecological questions posed by the PRDD simply remain vague, as do those provided by European and national policies and guidelines (such as the EU 2020 strategy for smart, inclusive, and green development).

61 From Ecology to Urbanism MÉTABOLISME URBAIN, RÉGION DE BRUXELLES CAPITALE MATIERES Parts et flux entrants (kt) FLUX entrants BRUXELLES FLUX sortants MATIERES Parts et flux sortants (kt) Autres Agriculture et 1 767 alimentation 2 039 Minéraux 2 239 Combustibles 2 215 Métallurgie 673 8 932 kt 75 kt 448 kt 6 770 kt déchets 1 730 kt Agriculture et alimentation Autres 1 376 1 758 Combustibles 726 Minéraux et Métallurgie 2 422 488 Précipitations 131 000 000 m STOCK MATERIEL Autres Bois Métaux Plastiques 143 1 147 3 517 1 420 Evapotranspiration 57 000 000 m 3 ENERGIE Parts et flux entrants (GWh) Industrie 596 Transport 5 472 Tertiaire 6 843 Logement 7 734 Gaz naturel 20 838 GWh Fioul* Electricité Produits pétroliers ENR** Charbon Cours d'eau 120 000 000 m 3 Eaux de distribution 66 000 000 m 3 Eaux usées (RF) 32 000 000 m 3 184 921 kt Non métaux 178695 3 2 100 000 m 130 000 000 m3 1 150 GWh Cours d'eau 272 000 000 m 3 GES Parts et flux sortants (kt eq.CO 2 ) Autres Gaz fluorés 118 214 Incinération 223 Résidentiel (énergie) 3 693 kt eq. CO 1 353 2 663 + chaleur et autres émissions Eaux usées 40 000 000 m 3 Transport routier 1 061 Industries (énergie) 63 Tertiaire (énergie) * Fioul léger, ** biodiesel, bioethanol, bois, autre biocarburant inclus Source : ICEDD – ECORES – BATir, pour le compte de la Région de Bruxelles Capitale, bilan provisoire avril 2014 Fig. 3: Metabolism of the Brussels Capital-Region. Diagram taken from research that investigates the functioning of urban systems in terms of direct and indirect resource requirements and the resulting environmental impact. EcoRes, ICEDD, and BATir, 2015. Meanwhile, the study of urban metabolism has not been widely applied in other cities in Europe and abroad, e.g., for tracking greenhouse gas emissions, measuring urban resource efficiency, or for sustainable design and planning (Clift et al. 2015). In line with those applications, three recent studies might provide some interesting insight into the state of the art of research and practice around the concepts of ecology and urban metabolism in Brussels. The first is the study Métabolisme de la Région de Bruxelles-Capitale developed by a consortium of consultants including the ULB (EcoRes et al., 2015) within the framework of the new Regional Program for a Circular Economy (PREC 2015). In order to assess resource efficiency and pollution emissions in Brussels, the study again draws on industrial ecology (EcoRes et al,. 2015). 6 The final report collects an exhaustive database of material and energy input and output flows at the level of the Brussels Region and is intended as a tool for achieving an optimal planning of its resources. The second, Metropolitan Landscapes, is a strategic design study launched by Brussels and Flemish authorities in 2014 that focused on building new visions for the landscape and open spaces that lay in between the two regions. It takes those open spaces as potential areas for urban expansion but also as rich and important natural reservoirs for the city of Brussels [Fig. 4]. Inspired by the work of Reyner Banham on Los Angeles (1973), the preliminary study identified four “ecologies” that comprise those spaces: the “valley of infrastructure,” the “constructed landscapes,” the “system of parks,” and the “wet landscapes.” In this case, the term “ecology” defines a “territorial figure”: a key rhetorical tool widely used by urbanists (e.g., Gerber