Developing an Urban Circular Economy Framework Based on Urban Metabolism

Abstract: There is an urgent need to transition to more sustainable cities and to do so we must identify in what ways and where cities are unsustainable. Urban metabolism offers a way to provide insight into how to move from linear to more sustainable, circular flows of energy and material in the urban area. Incorporating circular economy principles into the urban metabolism concept offers a promising way to reduce urban resource flows and increase the sustainability of the urban system. This thesis aims to combine an urban metabolism framework with circular economy indicators to create an urban circular economy framework, to support the transition towards more sustainable cities. This was achieved by identifying urban metabolism frameworks at the urban scale as well as several circular economy indicators, and then developing criteria for assessing them. It was found that several of the urban metabolism frameworks lacked an inclusion of hinterlands and a life cycle perspective, but provided various approaches to the urban metabolism. Assessment of the identified circular economy indicators showed that there is a lack of flow-based indicators that evaluate the social dimension of sustainability. To assess this in an adequate way there is a need to develop flow-based circular economy indicators, or alternatively urban metabolism frameworks which incorporate the social aspects. Furthermore, there is a need to develop more evaluation criteria and a categorisation for assessing the circular economy indicators. This would ensure that all sectors and some scales of delineation are addressed and provide a holistic understanding of the circular economy. Still, a somewhat holistic view can be gained from the combination of several indicators, as shown in the circular economy framework developed in this thesis. The framework was developed by combining a multilevel urban metabolism framework with 17 of the selected circular economy indicators. Out of these, 16 could be applied directly to the multilevel framework and together they cover all assessment criteria for circular economy indicators. This new framework is extensive and can be used to evaluate circular economy from a sustainable point of view. However, it is not fully holistic since it does not cover all sectors and could use a larger set of indicators. Still, by providing an example of an urban circular economy framework, this thesis offers a step towards the development of urban circular economy frameworks.