The comprehensive sustainability assessment of urban waste management systems (UWMSs) is crucial for understanding the impact of current and future city strategies aimed at improving circularity and inclusion in cities. In this study we propose a framework for conceptualizing the inclusive circular city (ICC), and we review specifically scientific literature on methodological tools and trends in integrated sustainability assessments (ISAs) of UWMSs. Of the 145 publications reviewed, only 10 % concurrently evaluated social, environmental, and economic aspects, and just 2 % incorporated circularity and inclusion metrics. Publications focusing simultaneously either on social and environmental dimensions or economic and environmental dimensions accounted for 3 % and 17 % of studies, respectively, while 70 % adopted a single-dimensional approach. A notable proportion of studies focused exclusively on environmental impact assessment, predominantly employing life cycle assessment or indicators such as carbon footprint. Social assessments were notably less prevalent, comprising only 20 % of studies. Stakeholder engagement and inclusion metrics were considered in 20 % and 5 % of the publications, respectively. In terms of R strategies, 65 % of the studies concentrated on recycling and recovery, targeting mainly municipal solid waste. To advance our knowledge on ISAs of UWMSs and improve our understanding of their embeddedness in ICCs, future research should: (a) focus on multidimensional, transdisciplinary assessments with an emphasis on strong sustainability-oriented methodologies by including circularity and inclusion metrics; (b) prioritize inclusion and active stakeholder participation in collaborative knowledge creation; and (c) shift the focus from conventional waste recycling and recovery to ambitious circular strategies that retain resources in closed-loop systems.@en

Purpose
We evaluate methodological approaches of different methods that can offer social assessments of product value chains. By analyzing both product-oriented social life cycle assessment (S-LCA) methods and qualitative, organization-, and project-oriented methods, we provide recommendations towards a clearer, harmonized method to better integrate the social dimension into sustainability assessments of products. This could help make S-LCA more analogous to environmental LCA (E-LCA) and more suitable for implementation in frameworks as life cycle sustainability assessment (LCSA).

Methods
We apply two quantitative S-LCA methods side-by-side with three qualitative social assessment methods on the same case-study of a textile’s value chain. The two quantitative S-LCA methods adopt a quantitative functional unit (FU) approach, use similar data structures and calculation principles as E-LCA and are based on the product social impact life cycle assessment (PSILCA) database. The three qualitative methods applied include two social due diligence approaches — one based on the OECD Due Diligence and UN Guiding Principles for Business and Human Rights and the other on the IFC Performance Standards — and the Subcategory Assessment Method (SAM), a semi-quantitative performance evaluation assessment method based on the UNEP S-LCA Guidelines.

Results
None of the approaches to S-LCA described in the UNEP S-LCA Guidelines can, at present, fully achieve the equivalent goals and scope of E-LCA, specifically in the social domain. Our evaluation of five social assessment methods, including two S-LCA methods, highlights their significant differences in basic structure and logic. Consequently, results differ considerably in nature, depth, and social aspects covered. Current product-oriented S-LCA approaches encounter important limitations as they require quantifiable aspects, whereas many social impacts are often qualitative in nature. Qualitative, organization-focused methods, conversely, make it difficult to link organizational social performance to specific products. Instead, these methods are typically used for social due diligence on suppliers in the company’s supply chain and cover only a small part of the product’s life cycle.

Conclusion
For the purpose of computational integration, LCSA frameworks need an S-LCA method with a quantitative FU approach. However, only some S-LCA approaches are able to comply with this requirement, and these will only be able to cover a limited set of scalable quantitative impact indicators. We conclude by emphasizing the equal importance of product-oriented S-LCA and organization-oriented social assessment methods, while appreciating their fundamentally different goals and scopes.@en

An ecological metaphor can enable transitions towards regenerative circular economies. Yet, this potential remains latent because its conceptual development, which is a prerequisite for its practical operationalization, is in its incipient phase and largely vague. To strengthen its epistemological underpinning, we propose a forward-looking interdisciplinary research agenda which brings together theories, ontological positions, analytical approaches, and strategies of action from ecological economics, panarchy theory, socio-metabolic research, process ecology, environ network theory, the constructal law, nature-based solutions, complexity economics, doughnut economics, regenerative economics, and ergodicity economics. The agenda facilitates the concentration, consolidation, and acceleration of theoretical and methodological innovation for the generation and accumulation of a diverse yet coherent body of knowledge on the interpretation of the process of regeneration and for illuminating the ways in which regenerative circular economies may function.

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With the latest IPCC report, dramatic global climate action must be taken immediately to limit global warming to 1.5 °C, or face more frequent and extreme weather events with catastrophic implications. Cities must invest in climate resilience development; however, government policies are only effective if they are supported by the society in which they serve. As such, this study aims to characterize the social perception of climate resilience development, in particular the implementation of sustainable urban rooftop strategies, to support policy makers and enable individual action. This was accomplished through the analysis of 1,100 answered surveys in Cerdanyola del Vallès (Spain), to assess one’s willingness to pay (WTP) and willingness to implement (WTI) rooftop strategies according to: 1. socio-demographical characteristics; 2. social perceptions and beliefs; and 3. surrounding land use and land cover, and vulnerabilities identified through temperature and normalized difference vegetation index (NDVI) maps. The results of this study found age played a significant role in predictability, with 18-39-year-olds being the most willing to pay and implement the various rooftop scenarios. However, our results uncovered societal inequality as those 85+ were the second group most interested in rooftop agriculture but the most financially restricted. Belief in the viability of rooftop strategies increased respondents WTP and WTI while having access to ones’ rooftop increased willingness to partake in rooftop food cultivation and enhance rooftop greenery. A new finding presented by this study is the quantifiable impact that urban greenery plays on increasing survey respondents WTP and WTI.

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Cities face the challenges of supplying food and managing organic municipal solid waste (OMSW) sustainably amid increasing urbanization rates. Urban agriculture (UA) can help with this effort by producing local crops that are fertilized with nutrients recovered from compost generated from OMSW. This research aims to determine the potential of OMSW compost to supply the nitrogen-phosphorus-potassium (NPK) demand of UA and the environmental benefits of replacing mineral fertilizer from a life cycle perspective. The Metropolitan Area of Barcelona (AMB) serves as the case study given its commitment to reuse biowaste according to the Revised Waste Framework Directive and to promote UA as a signing member of the Milan Urban Food Policy Pact. Based on crop requirements and farmer surveys, we find that the annual NPK demands of the agricultural fields of the AMB that cover 5,500 ha and produce 70,000 tons of crops are approximately 769, 113, and 592 tons of NPK, respectively. Spatial material flow analysis and life cycle assessment were applied to found that the current waste management system can potentially substitute 8 % of the total NPK demanded by UA with compost, reduce the impacts by up to 39 % and yield savings in global warming of 130 %. The more ambitious future scenario of 2025 can potentially substitute 21 % of the total NPK demand and reduce environmental impacts up to 1,049 %, depending on the category considered. Avoiding processing of mixed OMSW, mineral fertilizer replacement and cogeneration of electricity from biogas are the major contributors to these environmental savings.

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Considering the importance of waste metals for the transition to circular economies, this study follows a bio-inspired approach to evaluate their material and monetary global trade patterns for sustainability and equity. Between 2000 and 2022, the global trade grew by 5 % in trading countries, by 37 % in trade links, by 71 % in material flows, and by 569 % in economic flows. Driven by indirect effects, the average circulation of material and monetary flows ranged between 21.8–34.9 % depending on the demand or supply perspective but showed a declining trend. Due to homogenization, high network redundancy, and low network efficiency the trade remained robust yet outside the "window of vitality" characterizing natural ecosystems. A few, mostly high-income countries dominated the market, consolidating imports of high-value metal waste mostly from low- and middle-income exporters. Policies should address circularity and trade inequities, accounting for environmental and social ramifications throughout the lifecycle of products and materials.@en

Although the number of studies assessing the textile sector is increasing, only a few focus on its waste management. This study aims to shed light on current textile waste disposal practices and account for their environmental impact. To do so, a combination of citizen surveying and environmental quantitative tools, such as material flow analysis and life cycle assessment, are used to assess municipal textile waste in Catalonia in 2020. The results show that only approximately 10 % of municipal textile waste is separately collected, while 90 % is landfilled/incinerated. Of the 10 % of textiles collected separately, almost 40 % are prepared for reuse and recycled in Catalonia and Spain, approximately 40 % are exported for reuse and recycling in Asia, Africa and the rest of Europe, and the remaining 20 % are incinerated or landfilled, stocked or treated as improper waste. The carbon footprint generated by 1 t of textile waste managed by unseparated collection is 353 kg CO₂ eq, which almost double that of 1 t of textile waste collected separately: 207 kg CO₂ eq. The results also show that the emissions of textiles collected separately could be considerably reduced by minimizing their exports. The conclusions indicate that a proper course of action includes raising awareness about textile waste management and secondhand buying habits among citizens while investing in better sorting and local recycling technologies to reduce exports. Identifying the existing limitations to creating a local reuse and recycling textile sector is crucial to reduce its carbon footprint.

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The inclusion of the informal recycling sector (IRS) in a circular economy (CE) is challenging and it is gaining increasing attention by the academic community in an exponential yet fragmented way. In this narrative review, we demarcate the direct and indirect contributions of the IRS to various domains of the CE by drawing knowledge from relevant literature. First, we capture the modi operandi of different forms of recycling value chains into a typology. We do so based on distinct foci and policy approaches towards the IRS which have been adopted across different countries. Second, we synthesize various threads of information on reported forms of collaboration, tensions, and challenges in the context of urban waste management, into a conceptual framework to facilitate transitions towards circular and inclusive wise-waste systems. Finally, we discuss important aspects related to circular business models and integration approaches towards the IRS, and we propose avenues for further research.

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