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Publication

City Environmental Footprint. Development of a New Methodology to calculate Environmental Impacts of Cities

Book - Dissertation

Cities are complex entities which are constantly evolving, they are responsible for the largest share of most environmental impacts, but provide also major opportunities for improvement (EC 2011). Although holistic methodologies to evaluate the environmental footprint of cities are necessary, these are still lacking at the urban scale level. Indeed, few metrics already exist to evaluate and improve the sustainability of cities. One metric to gain insight in the material and energy flows to and from cities is the Urban Metabolism (UM) model that uses top-down approaches, such as Material and Energy Flow Analysis (MEFA) and input/output (I/O) analysis. UM clearly has it strengths as it makes an inventory of the flows into and out of the city, but it does not allow to interpret these flows in terms of environmental impacts. A first attempt to gain insights in the environmental consequences of these flows was done by Goldstein et al. (2013) to fuse the UM approach with the life cycle assessment (LCA) approach. The proposed UM-LCA translates the input-output flows within the city in terms of environmental impacts, but it considers only four environmental indicators. These do not represent the whole environmental picture as for instance the nine critical ecological boundaries of the earth (Rockström et al., 2009) and it is proved that considering just few impact categories may be misleading and increase the possibility of burdens shifting. Hence, extending the list of environmental impact categories is of paramount relevance to move towards a comprehensive and reliable environmental assessment method able to guide cities on a sustainable transition path. Furthermore, The two metrics mentioned (i.e. UM and UM-LCA) are both top-down approaches. These top-down approaches allow to gain insight in the most important flows going in and out of the city, but do not allow to analyze the parameters which are influencing these flows in depth on a micro-scale level. Insight in the effect of these micro-scale parameters is however necessary if the aim is to identify the priorities in terms of most effective measures to reduce the city's environmental impact. From the conviction that such insight is needed for real action taking and for engaging all stakeholders, the aim of this research proposal is to develop a hybrid approach, combining the typical top-down approaches with a bottom-up LCA approach. The research project aims at developing a hybrid (top-down and bottom-up approach) to identify the contribution of the main flows at the macro-scale level, but also the main hotspots on the micro-scale level and the potential improvements. This proposal hence contributes to the development of attractive, sustainable, and economically viable urban areas. It addresses both city governance issues and issues regarding vulnerability, resilience and adaptability. The main challenge is to develop a method which is more holistic and accurate than existing ones and to approach the challenge from bottom-up and top-down to allow for better insights in the main causes of the city's environmental impact. This research proposal departs from the hypothesis that if the environmental footprint of cities can be estimated accurately and if this footprint could be used for communication and inter-city comparison, it would be a powerful instrument to push cities in a more rapid transition towards sustainable entities. Such city environmental footprint (City EF) method would moreover allow to monitor the environmental performance of cities on a yearly base and would allow to identify the priorities in terms of efficient environmental impact reduction. Based on a combination of the top-down and a bottom-up analysis. a holistic environmental assessment method will be developed and tested to the city of Leuven. References: European Commission (EC) - DG Regions (2011). Cities of tomorrow. Challenges, vision, ways forward Goldstein B, Birkved M, Quitzau MB, Hauschild M, 2013. Quantification of urban metabolism through coupling with the life cycle assessment framework: concept and development and case study. Environmental Research Letters 8 (14 pp) Rockström, J., W. Steffen, K. Noone, Å. Persson, F.S. Chapin, III, E.F. Lambin, T.M. Lenton, M. Scheffer, C. Folke, H.J. Schellnhuber, B. Nykvist, C.A. de Wit, T. Hughes, S. van der Leeuw, H. Rodhe, S. Sörlin, P.K. Snyder, R. Costanza, U. Svedin, M. Falkenmark, L. Karlberg, R.W. Corell, V.J. Fabry, J. Hansen, B. Walker, D. Liverman, K. Richardson, P. Crutzen, and J.A. Foley, 2009: A safe operating space for humanity. Nature, 461, 472-475, doi:10.1038/461472a
Publication year:2022
Accessibility:Embargoed