Measuring Progress towards a Circular Economy: A Monitoring Framework for Economy‐wide Material Loop Closing in the EU28

The concept of a circular economy (CE) is gaining increasing attention from policy makers, industry, and academia. There is a rapidly evolving debate on definitions, limitations, the contribution to a wider sustainability agenda, and a need for indicators to assess the effectiveness of circular economy measures at larger scales. Herein, we present a framework for a comprehensive and economy‐wide biophysical assessment of a CE, utilizing and systematically linking official statistics on resource extraction and use and waste flows in a mass‐balanced approach. This framework builds on the widely applied framework of economy‐wide material flow accounting and expands it by integrating waste flows, recycling, and downcycled materials. We propose a comprehensive set of indicators that measure the scale and circularity of total material and waste flows and their socioeconomic and ecological loop closing. We applied this framework in the context of monitoring efforts for a CE in the European Union (EU28) for the year 2014. We found that 7.4 gigatons (Gt) of materials were processed in the EU and only 0.71 Gt of them were secondary materials. The derived input socioeconomic cycling rate of materials was therefore 9.6%. Further, of the 4.8 Gt of interim output flows, 14.8% were recycled or downcycled. Based on these findings and our first efforts in assessing sensitivity of the framework, a number of improvements are deemed necessary: improved reporting of wastes, explicit modeling of societal in‐use stocks, introduction of criteria for ecological cycling, and disaggregated mass‐based indicators to evaluate environmental impacts of different materials and circularity initiatives. This article met the requirements for a gold – gold JIE data openness badge described at http://jie.click/badges .     

Fostering sustainable land restoration through circular economy‐governed transitions

Soil and land are critical common pool resources offering a multitude of ecosystem services (ES) and presently affected by degradation and unplanned exploitation. The present article therefore attempts to elucidate the importance of circular economy in boosting land restoration and realization of several sustainable development goals through efficient waste recycling and clean energy production from degraded lands combined with policy restructuring for aligning circularity with restoration. Integrative policy frameworks targeting a “sustainable restoration economy” can help improve the cost feasibility of restoration projects through circularization of resource value chains besides enhancing social welfare and ecological vitality.     

基于生态效率的辽宁省循环经济分析

生态效率与循环经济相辅相成。基于区域生态效率评价是考量区域循环经济的重要内容,又基于目前对于循环经济与生态效率结合的实证研究相对较少,因此,以生态效率理论为基础,对我国最早开展循环经济的试点省份——辽宁省的循环经济发展作以综合衡量。通过生态效率度量模型与循环经济度量模型,以辽宁省1990～2008年数据为基础,运用基于熵权的TOPSIS方法,分别计算了19a间辽宁省各年的资源效率、环境效率、生态效率,进而综合评价了辽宁省循环经济发展轨迹。研究表明：在19a间,辽宁省生态效率总体呈现波动上升态势,经历了传统经济发展模式——末端治理模式——循环经济模式的转变;19a间,辽宁省循环经济发展状态总体上处于循环性不断增强的状态,即经济发展的同时,环境压力不断减小。研究证明了辽宁省2002年实行循环经济以来取得了明显成效,对全国尤其是东北地区发展循环经济,走新型工业化道路具有重要的示范意义。     

Cost versus environment? Combined life cycle,techno-economic,and circularity assessment of silicon- and perovskite-based photovoltaic systems

Photovoltaics will play a key role in future energy systems, but their full potential may not be realized until their life cycles are optimized for circularity and overall sustainability. Methods that quantify flows of compound and minor element mixtures, rather than non-mixed elemental flows, are needed to prospectively analyze and predict inventory and performance for complex technology life cycles. This study utilizes process simulation to resolve the mass and energy balances needed to rigorously analyze these complexities in circular systems. Using physics-based prospective inventory data, we simultaneously assess the environmental and techno-economic performance of three photovoltaic life cycles and predict the effects of circularity on resource efficiency, carbon footprint, and levelized cost of electricity. One inventory dataset is generated per life cycle to ensure alignment between assessments and to identify trade-offs between environmental and techno-economic performance with respect to circularity, so linking circularity and sustainability. The linked material and energy resource and techno-economic models allow for the impacts of carbon taxation and the moderating effects of circularity to be explored. In addition to the clear environmental benefits of increased circularity, we find that it could dampen the cost impact of taxation. While confirming that perovskite-based modules, single junction or in tandem with silicon, clearly outperform the silicon market standard both techno-economically and environmentally, we show that maximum circularity does not automatically deliver the most sustainable outcome. The approach enables assessment of the combined impacts of specific technological, commercial, and policy choices made by different actors along the photovoltaic value chain. This article met the requirements for a gold–gold JIE data openness badge described at http://jie.click/badges .      

A consequential approach to life cycle sustainability assessment with an agent-based model to determine the potential contribution of chemical recycling to UN Sustainable Development Goals

Chemical recycling (CR) could support a circular approach for municipal solid waste (MSW) treatment. In promoting the recirculation of recyclable carbon-containing waste as secondary feedstock for chemical production, it could contribute to resource conservation, emissions reduction, and supply security. To evaluate CR's contribution to the transition from a linear to a circular carbon economy—and correspondingly to the achievement of environmental, economic, and social sustainability as indicated in the UN Sustainable Development Goals (UN-SDGs)—this study builds on extant literature of life cycle sustainability assessment (LCSA) to investigate consequential environmental, economic, and social CR impacts. Specifically, an integrated approach whereby process-based life cycle assessment, techno-economic analysis, and social indicators are linked in the framework of an agent-based model is developed to investigate sustainability consequences of CR via gasification of residual MSW in Germany. Results suggest that CR contributes to reducing climate change and to addressing terrestrial acidification and fossil resource scarcity. However, its deployment will be associated with significant system costs. Hence, to promote CR implementation, measures such as obliging direct waste incineration to trade CO₂ certificates—provided that certificate prices increase sharply in the future—as well as implementing a recycling rate are found to be necessary to gap economic disadvantages. This study not only contributes to extending life cycle approaches for LCSA methodologically, it furthermore provides valuable insights into temporal and spatial interactions in waste management systems to inform science, industry, and politics about the sustainability impacts of CR on the achievement of the UN-SDGs. This article met the requirements for a gold-gold JIE data openness badge described at http://jie.click/badges .      

An aggregation framework to link indicators associated with multifunctional land use to the stakeholder evaluation of policy options

In the last decade efforts have been carried out by the scientific community aimed at building integrated frameworks to support the decision-making process when sustainability issues are addressed. This paper proposes a further advancement in integrated assessment procedures by setting up an operational multi-scale and transparent framework, which comprises the assessment of European regions in terms of sustainability, and the identification of the impact that policy options might have on the sustainability of these regions. The framework is designed for use in ex ante sustainability impact assessment of policy scenarios on multifunctionality of land use and integrates economic, environmental and social issues across a variety of sectors (agriculture, forestry, transport, tourism and energy). The proposed method provides a conceptual framework applicable at different scales (European, regional), and takes into account the great variability of European regions. The described methodology is based on linear additive models to weight and aggregate selected indicators to a set of land use functions identified to describe the goods and services provided by the different land uses that summarise the most relevant economic, environmental and social issues of a region. The framework is designed to allow the evaluation of impacts at an international scale (e.g. the European Union), or on selected regions.The aggregation framework can be used to evaluate the impact that policy options have on the sustainability of multifunctional land use systems with competing demands. A conceptual envelope, called the “trade-off evaluation space”, delineates all possible developments in the functions of the land. The sustainability limits identify the subset of ‘acceptable’ policy options within the trade-off evaluation space, so that the distance of each land use function from sustainability limits can be estimated and trade-offs between the different functions of the multifunctional land use system can be identified. The proposed methodology is adaptable to different contexts: if the assumption is taken that all land use functions are equally weighted the framework can be used to analyse policy cases and take decisions on policy options at the European or regional level. However, at the local-scale the framework can also be applied through a participatory approach and the distribution of weights can be rediscussed with local stakeholders. In both cases the proposed system can be used as a tool for discussion among all interested parties.     

A framework to open the black box of the use phase in circular economy life cycle assessments: The case of shell jacket reuse

Life cycle assessments of circular economy measures (CE LCA) of consumer products have been criticized for oversimplifying important aspects of the use phase such as user behavior and rebound effects, limiting our understanding of the environmental performance of circular economy measures. This study tests the usefulness of a framework designed to facilitate accounting for such aspects, by applying the framework to a case study of reuse of shell jackets enabled by “premium secondhand” outdoor stores. Methods for collecting use phase data were user surveys and interviews with store managers. Using the framework on this case study generated several novel insights which are interesting in themselves and as inputs to CE LCA. For instance, secondhand shell jackets have a significantly lower frequency of use during their first use span compared to the second and to shell jackets in the linear reference scenario. This implies that reuse in this case does not function as a mere use extension of otherwise similar use phases as is commonly assumed. The generation of such insights, which hitherto have been lacking in CE LCAs, points to the usefulness of the framework as a tool for opening the “black box” of the use phase in CE LCAs to improve understanding of the environmental performance of circular economy measures.     

The current and potential role of urban metabolism studies to analyze the role of food in urban sustainability

Food supply chains are essential for urban sustainability. To reflect on the state of knowledge on urban food flows in urban metabolism research, and the actual and potential role of urban metabolism studies to tackle food sustainability in cities, we systematically review scientific research on food from an urban metabolism perspective and apply statistical and thematic analyses. The analysis of 89 studies provides insights as to the relation between food supply and (environmental and social dimensions of) urban sustainability. First, food is an important contributor to urban environmental impacts, if a consumption-based approach is adopted. Secondly, the social impacts of urban food supply remain scarcely studied in urban metabolism research, but emerging results on public health, malnutrition, and food waste appear promising. In parallel, we find that the findings of the studies fail to engage with debates present in the broader literature, such as that of food justice. Our analysis shows that most studies focus on large cities in high-income, data-rich countries. This limits our understanding of global urban food supply. Existing studies use innovative mixed-methods to produce robust accounts of urban food flows in data-scarce contexts; expanding these accounts is necessary to get a better understanding of how urban food supply and its diverse impacts in terms of environmental and social sustainability may vary across cities, a necessary step for the urban metabolism literature to contribute to current debates around food sustainability and justice.     

On the global limits of bioenergy and land use for climate change mitigation

Across energy, agricultural and forestry landscapes, the production of biomass for energy has emerged as a controversial driver of land‐use change. We present a novel, simple methodology, to probe the potential global sustainability limits of bioenergy over time for energy provision and climate change mitigation using a complex‐systems approach for assessing land‐use dynamics. Primary biomass that could provide between 70 EJ year^?1 and 360 EJ year^?1, globally, by 2050 was simulated in the context of different land‐use futures, food diet patterns and climate change mitigation efforts. Our simulations also show ranges of potential greenhouse gas emissions for agriculture, forestry and other land uses by 2050, including not only above‐ground biomass‐related emissions, but also from changes in soil carbon, from as high as 24 GtCO₂eq year^?1 to as low as minus 21 GtCO₂eq year^?1, which would represent a significant source of negative emissions. Based on the modelling simulations, the discussions offer novel insights about bioenergy as part of a broader integrated system. Whilst there are sustainability limits to the scale of bioenergy provision, they are dynamic over time, being responsive to land management options deployed worldwide.     

Ecosystem Approaches to Human Health and Well-being: Reflections from Use in a Mining Context

This article briefly discusses the evolution of ecosystem approaches, and illustrates the use of ecosystem approaches to assess human health and well-being in a mining context. It discusses the various elements that help distinguish such approaches from other approaches. Well-being here is understood broadly in terms of its “constituents” and “determinants,” of which health is an important constituent. Ecological, health, and social assessments highlighted a number of impacts from mining activity in Goa, India. These generated a list of issues of concern that were validated by stakeholders—community, industry, and government—which served as a basis for the development of tools to track mining-induced changes in health and well-being. The article concludes by reflecting on some of the challenges posed by the use of ecosystem approaches to assessing human health and well-being.     

Visions of Nature and Environmental Sustainability: Shellfish Harvesting in the Dutch Wadden Sea

The concept of sustainability has several, sometimes contrasting, meanings that may generate confusion, misunderstanding, and conflict concerning conservation and restoration practices. It is therefore desirable to clarify the concept of sustainability, thereby potentially contributing to mutual understanding, especially when social conflicts arise. This article discusses a recently published typology of three conceptions of sustainability that range from economic to ecocentric valuations of nature. We argue that the typology is incomplete because it does not include the arcadian approaches. For this reason, we introduce a “tripolar model” for conceptions of sustainability, applying it to the debate on shellfish harvesting in the Dutch Wadden Sea. We conclude that the particular visions or conceptions of sustainability held by relevant actors may have an impact on strategies for conservation.     

Lessons,narratives, and research directions for a sustainable circular economy

The current enthusiasm for the circular economy (CE) offers a unique opportunity to advance the impact of research on sustainability transitions. Diverse interpretations of CE by scholars, however, produce partly opposing assessments of its potential benefits, which can hinder progress. Here, we synthesize policy-relevant lessons and research directions for a sustainable CE and identify three narratives—optimist, reformist, and skeptical—that underpin the ambiguity in CE assessments. Based on 54 key CE scholars’ insights, we identify three research needs: the articulation and discussion of ontologically distinct CE narratives; bridging of technical, managerial, socio-economic, environmental, and political CE perspectives; and critical assessment of opportunities and limits of CE science–policy interactions. Our findings offer practical guidance for scholars to engage reflexively with the rapid expansion of CE knowledge, identify and pursue high-impact research directions, and communicate more effectively with practitioners and policymakers.     

The Environmental Impacts of Consumption at a Subnational Level

This article analyzes the environmental effects of resource consumption at a subnational level (by Cardiff, the capital city of Wales), using the Ecological Footprint as a measure of impact assessment. The article begins by providing a short critique of the Footprint methodology and the limitations of methods traditionally used to calculate national Footprint accounts. We then describe the Footprint methodology developed by the Stockholm Environment Institute to overcome some of these problems and used as the basis of the Reducing Wales' Ecological Footprint project, of which the Cardiff study has been a part. The main portion of this article focuses on presenting and discussing the Footprint results for Cardiff. The Ecological Footprint of household consumption in Cardiff will be presented using the international Classification of Individual Consumption According to Purpose (COICOP). Based on the results, we found that the areas of consumption that are a priority for Cardiff in terms of reducing resource use are food and drink, passenger transport (car and aviation), domestic fuel consumption, waste, and tourism. We also discuss how these findings have been presented to the Cardiff Council. We report on the initial reactions of policy officers to the Footprint results and how the Council plans to use them to influence policy decisions relating to sustainability. Finally, in the Conclusions section, we briefly explain the value of applying the Ecological Footprint at a subnational level and its value as an evidence-based tool for sustainability decision making.     

Plastic value chain and performance metric framework for optimal recycling

Despite the promotion of plastic recycling to sustainably manage plastic waste and advance the circular economy, existing plastic recycling systems globally are largely experiencing low performance and growth. To transition to world-class plastic material recycling and circularity, defining the metrics that impact the performance of a plastic recycling system is crucial. Bringing together existing literature, this study developed a conceptual framework, comprised of eight key performance metrics, for benchmarking recycling success or assessing the degree to which the performance of any plastic recycling system is optimal. Through a value chain approach, the specific performance metrics relevant to each stage of the plastic recycling system, their objectives, and the actors characterizing the system were analyzed in detail. Also, specific maturity models were developed to measure the performance of any plastic recycling system. This framework provides essential knowledge for related stakeholders to inform further development of plastic recycling and a circular economy.     

Quality Assessment and Circularity Potential of Recovery Systems for Household Plastic Waste

Plastic recycling is promoted in the transition toward a circular economy and a closed plastic loop, typically using mass‐based recycling targets. Plastic from household waste (HHW) is contaminated and heterogeneous, and recycled plastic from HHW often has a limited application range, due to reduced quality. To correctly assess the ability to close plastic loops via recycling, both plastic quantities and qualities need to be evaluated. This study defines a circularity potential representing the ability of a recovery system to close material loops assuming steady‐state market conditions. Based on an average plastic waste composition including impurities, 84 recovery scenarios representing a wide range of sorting schemes, source‐separation efficiencies, and material recovery facility (MRF) configurations and performances were assessed. The qualities of the recovered fractions were assessed based on contamination and the circularity potential calculated for each scenario in a European context. Across all scenarios, 17% to 100% of the generated plastic mass could be recovered, with higher source‐separation and MRF efficiencies leading to higher recovery. Including quality, however, at best 55% of the generated plastic was suitable for recycling due to contamination. Source‐separation, a high number of target fractions, and efficient MRF recovery were found to be critical. The circularity potential illustrated that less than 42% of the plastic loop can be closed with current technology and raw material demands. Hence, Europe is still far from able to close the plastic loop. When transitioning toward a circular economy, the focus should be on limiting impurities and losses through product design, technology improvement, and more targeted plastic waste management.     

A social panorama within the life cycle thinking and the circular economy: a literature review

Purpose

This literature review aims to present the current methodologies that have been developed to perform a social life cycle assessment (sLCA) and to display the main differences among them. In addition to that, to identify the nexus between sLCA and circular economy (CE) and to what extent this life cycle technique has been involved within CE studies.

Methods

An analysis of scientific literature using online databases was made. A total of 76 publications, including all industry sectors worldwide, were chosen spanning 11 years, from 2009 to 2020. Special attention was made to the methodology used to assess the social impacts, the impact categories analyzed, and whether there is or not a circular economy case. All the impact categories of both UNEP/SETAC and PSIA were taken into account when doing the review, and the top three of the categories are mentioned here.

Results and discussion

The leadership of the UNEP/SETAC methodology is clear with 58 cases. Almost 90% of the case studies are focused on products while the remaining ones are related with services. Workers are the most considered stakeholder when conducting an sLCA research, followed by local communities and society. Regarding the impact assessment, the performance reference point (PRP) was the most common method used. When considering the CE even when some cases included the end-of-life stage in the system boundaries, the studies did not consider the actors from that stage; excluding these cases, one out of four articles has a link with CE, a promising proportion taking into account the early stage of both concepts (i.e., sLCA and CE).

Conclusions

UNEP/SETAC guidelines seem to be the most promising methodology due to its reception among the scientific community. However, a more industry-oriented approach is proposed by the Roundtable for Product Social Metrics (PSIA) in a way to respond to manufacturing companies’ demand. Regardless of the type of methodology to be implemented, workers represent the key stakeholder when assessing social impacts. The change in usual patterns is leading to a change in the way how stakeholders interact and therefore new and more impacts may arise, and that is the reason why it is important to include the CE into the sLCA. A series of challenges such as the feasibility of aggregating all the life cycle techniques to one (life cycle sustainability assessment), data availability, and quality are still present for the moment.

     

An overview of sustainability assessment methodologies

Sustainability indicators and composite index are increasingly recognised as a useful tool for policy making and public communication in conveying information on countries and corporate performance in fields such as environment, economy, society, or technological improvement. By visualizing phenomena and highlighting trends, sustainability indicators simplify, quantify, analyse and communicate otherwise complex and complicated information.There are number of initiatives working on indicators and frameworks for sustainable development (SD). This article provides an overview various sustainability indices applied in policy practice. The paper also compiles the information related to sustainability indices formulation strategy, scaling, normalisation, weighting and aggregation methodology.     

Material Flow and Ecological Restructuring in China

Environmental problems are closely related to society' processing of materials through the entire economy. Because neither traditional environmental nor economic analytical methods can provide sufficient insight into the physical dimension of economies, this article presents an integrated methodology, combining a substance flow analysis (SFA) approach and an ecological restructuring analysis. This approach is applied to phosphorus (P) in China, one of the most rapidly growing industrializing economies, in order to better understand of the economy's material use and its change over time. A static national SFA model is developed with statistical data from 1996. By tracking the national economy's P flows from origins to destinations, the critical P flows with respect to environmental impacts are identified. Based on the regime of national P flows, this article analyzes the degree of ecological restructuring by dynamically describing the structural changes of related critical P flows over the last two decades with a set of ecological restructuring indicators (ERIs). Finally, some potential and desired changes are discussed, with the goal of ecologizing the national P flow regime; that is, reducing the ecological impact of the national P flow regime. The methodology of this article illustrates its applicability and value for presenting an overall insight into the physical dimensions of national economies.     

Progress in sustainability science: lessons learnt from current methodologies for sustainability assessment: Part 1

Purpose

Sustainability Science (SS) is considered an emerging discipline, applicative and solution-oriented whose aim is to handle environmental, social and economic issues in light of cultural, historic and institutional perspectives. The challenges of the discipline are not only related to better identifying the problems affecting sustainability but to the actual transition towards solutions adopting an integrated, comprehensive and participatory approach. This requires the definition of a common scientific paradigm in which integration and interaction amongst sectorial disciplines is of paramount relevance. In this context, life cycle thinking (LCT) and, in particular, life cycle-based methodologies and life cycle sustainability assessment (LCSA) may play a crucial role. The paper illustrates the main challenges posed to sustainability assessment methodologies and related methods in terms of ontology, epistemology and methodology of SS. The aims of the analysis are twofold: (1) to identify the main features of methodologies for sustainability assessment and (2) to present key aspects for the development of robust and comprehensive sustainability assessment.

Methods

The current debate on SS addressing ontological, epistemological and methodological aspects has been reviewed, leading to the proposal of a conceptual framework for SS. In addition, a meta-review of recent studies on sustainability assessment methodologies and methods, focusing those life cycle based, supports the discussion on the main challenges for a comprehensive and robust approach to sustainability assessment. Starting from the results of the meta-review, we identified specific features of sustainable development-oriented methods: firstly, highlighting key issues towards robust methods for SS and, secondly, capitalising on the findings of each review’s paper. For each issue, a recommendation towards a robust sustainability assessment method is given. Existing limitations of sectorial academic inquiries and proposal for better integration and mainstreaming of SS are the key points under discussion.

Discussion

In the reviewed papers, LCT and its basic principles are acknowledged as relevant for sustainability assessment. Nevertheless, LCT is not considered as a reference approach in which other methods could also find a place. This aspect has to be further explored, addressing the lack of multi-disciplinary exchange and putting the mainstreaming of LCT as a priority on the agenda of both life cycle assessment and sustainability assessment experts. Crucial issues for further developing sustainability assessment methodologies and methods have been identified and can be summarised as follows: holistic and system wide approaches, shift from multi- towards trans-disciplinarity; multi-scale (temporal and geographical) perspectives; and better involvement and participation of stakeholders.

Conclusions

Those are also the main challenges posed to LCSA in terms of progress of ontology, epistemology and methodology in line with the progress of SS. The life cycle-based methodologies should be broadened from comparing alternatives and avoiding negative impacts, to also proactively enhancing positive impacts, and towards the achievement of sustainability goals.