Assessing the contribution of Circular Economy to Urban Sustainability: an analysis based on the use of indicators

Currently our world is becoming increasingly urban, with around 50% of its population living in cities. Whereas cities produce 80% of the worldwide GDP and are places with high innovation, they also consume 75% of worldwide resources and produce 80% of CO2 emissions. Thus, achieving urban sustainability will be crucial in the future. To reduce resource consumption in cities, Circular Economy has been proposed as a key concept, i.e. using resources more efficiently through value retention processes and minimizing the waste produced. Although the concept of the Circular Economy is not new, its potential contribution to Urban Sustainability still needs to be elicited. How does the Circular Economy conceptually integrate and, contribute to, Urban Sustainability? To answer this question, we focused on how the transitions towards the Circular Economy and towards Urban Sustainability are currently assessed. We conducted a cluster analysis of approximately 50 sets of indicators. Roughly half of the sets are currently used by municipalities or institutions to track the progress of cities towards the Circular Economy; the others cover Urban Sustainability. Each set contains approximately 40 indicators, although the number varies greatly. From each set, we extracted single indicators and categorized them according to conceptual frameworks, namely the three pillars of sustainability and the Sustainable Development Goals. We analyzed the overlap between the sets to derive clusters. We hypothesized that it should be possible to detect two clusters of sets of indicators: one referring to Circular Economy, one to Urban Sustainability. This would emphasize the differences in how the transitions towards Circular Economy and Urban Sustainability have been assessed, through the choice of distinct indicators. Our results will have both theoretical and practical contributions, informing the debate on the differences and overlaps between the two concepts and supporting urban communities in developing ad-hoc sets of indicators.

Scrutinizing the Circular Economy concept applied at the urban level:A contribution based on the analysis of urban circularity indicators, the categorization ofCircular Economy interventions, and the identification of factors fostering the adoption ofcircular innovation.

Valeria Superti

Problem. Our current economic systems are deemed unsustainable. Although a global issue, the objective of living in a sustainable society is increasingly an urban challenge, as a rising 50% of the world's population currently dwell in cities. To secure a better urban future, integrated and actionable urban knowledge focused on what urban sustainability entails and how to achieve it is needed. In this context, the Circular Economy (CE) concept fosters efficient resource use through value-retention processes and waste minimization. Despite the wide attention on the CE, its interconnectedness with, and contribution to, sustainability, and whether these concepts might support or hinder each other, have not yet been clarified. Besides, knowledge is needed to guide cities towards a CE, for example, by identifying the types of interventions needed to achieve circularity, and the factors affecting the adoption of innovation that can foster it.Aim. This dissertation aims to scrutinize the CE concept applied in urban settings. It is based on a) the analysis of indicators used to assess circular cities, b) the categorization of interventions aimed at achieving a CE, and c) the identification of factors that affect the adoption of recycled products, as one measure towards CE.Approach. Indicators used to assess circularity and sustainability in urban settings were analyzed and compared. Semi-structured expert interviews were performed to iterate a framework that categorizes interventions that foster the achievement of a CE. A behavioral framework was developed that combines insights from the theory of adoption of innovation and behavioral theories, to identify and analyze the factors that can affect architects' decisions to recommend recycled concrete. A survey was used to gather quantitative insights from architects on their beliefs about the selected product.Insights. The results show that the concept of an urban CE is embedded in the broader concept of urban sustainability; however, the use of CE indicator sets entail a more detailed focus on certain thematic groups (e.g., waste production and management), for which more indicators are available in comparison with what offered by urban sustainability indicator sets. To categorize CE interventions, the proposed framework (RISE: Research & Realize, Implement, Support, Enable) offers a tool to guide the achievement of CE targets. In current circularity assessments, specifically in the construction sector, most attention is paid to implementation interventions (e.g., the quantity of material recycled). However, some of them (e.g., recycling strategies) still face barriers. Focusing on one recycling strategy (i.e., recycling concrete aggregates for recycled concrete) we inquired about the factors that affect this product's adoption. A senior position, a high level of knowledge of the material and a specific label, beliefs about the material's lower environmental impact, and prescriptive social norms affect the selected innovation's adoption. Finally, we suggest leveraging specific predictors of behavior to increase the recommendation of recycled concrete.Conclusions. This work contributed to shed light on the CE concept. This research challenged the added value of focusing on a CE rather than sustainability. Furthermore, it put forward a) an integrative perspective on achieving a CE focusing on a systemic approach, and b) a holistic behavioral framework for analyzing innovation adoption.

EPFL2021

Unraveling how the concept of circularity relates to sustainability: An indicator-based meta-analysis applied at the urban scale

Claudia Rebeca Binder Signer, Albert Merino, Valeria Superti

Cities account for 75% of resource consumption and 80% of CO2 emissions. With rising urbanization, achieving urban sustainability becomes crucial. The Circular Economy (CE) concept has been proposed to reduce resource consumption, although its link to sustainability remains unclear from theoretical and practical perspectives. This paper provides an in-depth comparative analysis of 57 indicator sets used in academia or practice to measure either CE in urban areas or urban sustainability. Indicators were extracted and categorized according to three conceptual frameworks, namely: the STEEP categories, the Sustainable Development Goals, and inductively-created thematic groups. The similarities among the 57 sets were analyzed to derive clusters. Results show that CE represents a subset of urban sustainability, while offering more indicators to assess specific thematic groups (e.g., waste). In the discussion, the value added by targeting a CE rather than sustainability is questioned, and insights are provided to support actors involved in an urban transition to develop well-informed city targets. The results offer theoretical, practical, and methodological contributions, and aid involved actors, especially those leading urban transition agendas, to unravel the conceptual link between CE and sustainability, specifically at the urban scale.

2021

Méthodologie de gestion durable des ressources du sous-sol urbain

Pascal Blunier

The world is becoming more and more urban. During the last fifty years, the population in Swiss cities has grown from 45% to 70% of the total population. This change is characterised by urban sprawl and by an increase in the consumption of resources, particularly those coming from rural areas. This evolution is not compatible with the principles of sustainable development. To solve this problem, new urban policies are being developed. They favour development within the urbanised areas and reduced use of exogenous resources. The urban underground contains resources – space, geomaterials, groundwater and geothermal energy – which can efficiently support such policies. This project analyses how these resources have been exploited until now and how they could be used with sustainability in mind. The use of underground resources was analysed in five cities : Mexico, Paris, Helsinki, Tokyo and Montreal. It appears that, although resources participate in the urban metabolism, there is an important lack of planning and coordination in their use. Developments follow a sectional approach where the resources are considered independently, and only at the scale of a given construction project. As a consequence, conflicts occur between uses and resources are wasted. An understanding of the urban underground as a system was developed with the aim of preventing conflicts and promoting synergies. To this effect, the way in which resources interact was considered attentively. Situations in which interactions occur were described and analysed and compatibility conditions were suggested. A methodology was elaborated to evaluate the resource potential of an urban underground. It aims at considering the resources and the interactions between their uses from the beginning of the process of urban planning. The methodology is based on the use of Geographical Information Systems and 3-D modelling of geological and hydrogeological conditions. It aims at reversing the current paradigm, that proceeds from the needs to the resources, into an approach based on resources to satisfy the needs. Spatial information was exploited to determine indicators and maps of potentiality and of restrictions. The derived results will help support decision making by planners and policy makers who seek to better exploit the resources from the urban underground. The methodology was tested and applied on a case study : Geneva. The developed approach allows more efficiency in the use of urban underground resources, it can help prevent conflicts between uses and develop synergies. When integrated in the urban planning process, it highlights new opportunities and helps to develop projects that take into account the physical conditions of the underground.

EPFL2009

Méthodologie de gestion durable des ressources du sous-sol urbain

Pascal Blunier

EPFL2009

Valeria Superti

EPFL2021