Diversifying supply chains through reshoring and friendshoring is increasingly proposed as a key strategy for supply security and resilience. Quantitative analyses characterizing to what extend diversification shield countries from supply disruptions remain however scarce. In this paper, we present a methodology to assess the supply risk exposure of countries in different supply diversification scenarios – business-as-usual, reshoring, friendshoring. For each scenario, the propagation of three types of upstream disruptions – supply shortage, export restriction, bilateral trade conflict – is simulated. A fragility ratio metric is introduced to quantify the potential downstream shortages caused by these disruptions. A novel friendshoring modelling approach is also proposed. It consists in determining risk-optimized trade relations based on criteria such as supply concentration and UN voting similarity. The Python-based model is tested on the case of diversified photovoltaics supply chains, e.g., if the US, EU, and India increase domestic production from polysilicon to module. Beyond building up manufacturing capacities, choosing between vertical integration and trade is highly determinant in risk exposure. Each diversification scenario shows pros and cons depending on the country and process considered. Overall, this paper underlines the need for supply risk research to nuance diversification recommendations. It would be particularly helpful to improve indicators accounting for a region's technical and economic ability to supply a given product, and to realistically model the challenges of reshoring.

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Widespread adoption of electric vehicles poses challenges due to critical raw material (CRM) requirements. The European Union (EU) is now dependent on other countries for supply of these materials, but wants to increase self-sufficiency for primary extraction to 10 % in 2030. Here we map and quantify Europe's raw material reserves and resources, revealing promising deposits for most minerals. Our analysis indicates that, assuming a high development scenario, for lithium, nickel and copper the planned extraction in Europe is sufficient to meet at least 10 % ofdemand for E-mobility in 2030, as the EU's proposed target dictates. The projected extraction of cobalt, natural graphite and REE, will probably not reach 10 % of the demand in 2030. For REE there is no European production projected. To meet these targets and increase the EU's self-sufficiency, CRM extraction in Europe needs to increase, in parallel with implementing circular economy efforts to reduce material demand.

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Rare earth elements (REEs) are vital to the development of low-carbon technologies. There are rising concerns in the United States and elsewhere about REE supply chain stability and risks given the unvalidated perception in the heavy reliance of China, by far the largest REE supplier. However, the relationship between key countries at different stages of global REE supply chains remains unclear. Here, we use a dynamic flow analysis to explore supply dependence between the United States and China by tracing REE flows from mineral mining to market between 2000 and 2022. Our results indicate complementary and cooperative US–China interactions, especially after 2018 when the United States became a net exporter of REE and China's largest supplier, and China became the largest importer of the US REEs and manufacturer of REE-enabled low-carbon technologies. This intensifying interdependence stabilizes REE supply chains and highlights the importance of cooperative REE trade networks.

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Tin is an important metal for society with a high risk of supply disruptions. It is, therefore, classified as a critical material in many parts of the world. An exception is the European Union, for which tin was classified as a non-critical material in 2023. However, there are many discrepancies in the literature regarding the definitions and values of the indicators used to determine tin criticality in general, and recycling indicators in particular. Values for end-of-life recycling rate (EoL RR) range between 20% and 75%, and values for end-of-life recycling input rate (EoL RIR) range between 11% and 32%. In this paper, we critically assess the circularity and criticality indicator values for tin and calculate new values using material flow analysis. The new values for tin recycling indicators are lower than those used in most previous research, with a global EoL RR of 16% and an EoL RIR of 11% in 2017. Based on the updated recycling values, combined with a highly concentrated supply, high import reliance, and difficult substitution, we argue that the European Union should classify tin as a critical material. This reclassification can lead to more policy attention for tin, which can help reduce the impact of future supply disruptions and increase the resilience of the European and global tin supply chains.

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Silicon carbide (SiC) is a niche nonmetallic material that is essential in many industrial processes. Here, we integrate material flow analysis and supply chain resilience analysis to understand global SiC stocks and flows and to assess its supply chain. We use industry interviews to fill data gaps and collect information on the SiC system to overcome data scarcity. We find that globally around 1000 kt of SiC is produced each year. The biggest use of SiC is the abrasives industry (40%), followed by metallurgy (28%), refractories (20%), technical ceramics (0.7%), other uses (0.7%), and semiconductors (0.01%). As an energy-intensive material, the SiC supply chain is under pressure, increasing the relevance of resilience considerations. Besides typical supply chain risks such as low diversity of supply and geopolitical trade restrictions, SiC particularly faces risks due to its energy-intensive production process and associated emissions. In the SiC semiconductor supply chain, losses of nearly 75% are a particular issue. Due to high demand in the SiC market, stockpiles are negligible, and substitution is difficult in most sectors. We find that in the case of SiC, sustainability measures such as use reduction, recycling, or decreasing energy use or emissions would also positively contribute to supply chain resilience. This article met the requirements for a gold-gold JIE data openness badge described at http://jie.click/badges.

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Each year, consumers return billions of new products to retailers. Despite growing concern over product destruction, post-return product flows are not well understood, and the full lifecycle environmental impacts of returns remain largely unknown. Building on a unique dataset covering over 630k returned apparel items in the EU, we map the flow of returned products under sustainable and conventional management practices, and quantify the full lifecycle impacts associated with returns using two illustrative apparel case studies. We find that 22%-44% of returned products never reach another consumer. Moreover, the GHG emissions associated with the production and distribution of unused returns can be 2–16 times higher than all post-return transport, packaging, and processing emissions combined. Our findings suggest that the environmental impacts eCommerce and specifically online apparel, may be systematically underestimated when returns are not accounted for, and highlight the urgent need to promote circular management practices that maximize use of returned products.

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As the aviation industry strives to minimise its environmental footprint, understanding the full life cycle impacts, including maintenance, becomes essential for sustainable development. This paper addresses the critical research gap in the environmental assessment of aircraft maintenance by conducting a comprehensive life cycle assessment based on an Airbus A320 aircraft. By combining a top-down check-level analysis and a detailed examination of the aircraft manufacturer's maintenance planning document, this study provides significant insights into the environmental implications of maintenance activities. The check-level analysis provides a general overview, while the analysis of the maintenance planning document delves into individual tasks, enabling the identification of components with the highest ecological impacts. This research emphasises the importance of including aircraft maintenance activities in life cycle assessment studies and provides valuable guidance for researchers, industry practitioners, and policy makers in prioritising sustainability measures and enhancing the environmental performance of aircraft throughout their life cycle.

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The anticipated increase in urban population of 2.5 billion people by 2050 poses significant environmental challenges. While the various environmental impacts of urbanisation have been studied individually, integrated approaches are rare. This study introduces a spatially explicit model to assess urbanization’s effects on ecosystem services (green infrastructure availability, cooling, stormwater retention) and the environmental impact of building construction (material demand, greenhouse gas emissions, land use). Applied to the Netherlands from 2018 to 2050, our results show that integrating green infrastructure development with building construction could increase green areas by up to 5% and stabilize or increase ecosystem service provisioning. Dense building construction with green infrastructure development is generally more beneficial across the Netherlands, reducing resource use and enhancing ecosystem services. Conversely, sparse construction with green infrastructure is more advantageous for newly built areas. These findings offer insights into the environmental consequences of urbanization, guiding sustainable urban planning practices.

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Bio-based polymers may present a sustainable, circular way to reduce the environmental impact of plastics because they are produced from biomass that absorbs CO₂ during its growth. However, sourcing (type of biomass used and cultivation location), production, and end-of-life affect the environmental impact of bio-based plastics. We assessed the effect of sourcing and end-of-life options on the environmental impact of bio-based high-density polyethylene (bio-HDPE) in 31 sourcing scenarios and five end-of-life options. Our study found that careful consideration of biomass sourcing (biomass type and production location) and end-of-life is needed to optimize the environmental impact of bio-based plastics. If these aspects are not considered, the environmental impact of bio-HDPE may exceed that of its petrochemical-based counterpart. The direct availability of fermentable sugars indicated a lower environmental impact. The production location affected the resources needed for biomass cultivation and the environmental impact of processing due to the energy mix. Recently published guidelines do not allow biogenic carbon to be accounted for during the production stage, but only upon the incineration of the plastic. Our results show that this way of attributing biogenic carbon results in an apparent disadvantage for bio-based plastics compared to petrochemical-based plastics. Furthermore, it disadvantaged mechanical recycling of bio-based plastics compared to incineration, a result out of line with circular economy principles.

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Underfunded healthcare infrastructures in low-resource settings in sub-Saharan Africa have resulted in a lack of medical devices crucial to provide healthcare for all. A representative example of this scenario is medical devices to administer paracervical blocks during gynaecological procedures. Devices needed for this procedure are usually unavailable or expensive. Without these devices, providing paracervical blocks for women in need is impossible resulting in compromising the quality of care for women requiring gynaecological procedures such as loop electrosurgical excision, treatment of miscarriage, or incomplete abortion. In that perspective, interventions that can be integrated into the healthcare system in low-resource settings to provide women needing paracervical blocks remain urgent. Based on a context-specific approach while leveraging circular economy design principles, this research catalogues the development of a new medical device called Chloe SED® that can be used to support the provision of paracervical blocks. Chloe SED®, priced at US$ 1.5 per device when produced in polypropylene, US$ 10 in polyetheretherketone, and US$ 15 in aluminium, is attached to any 10-cc syringe in low-resource settings to provide paracervical blocks. The device is designed for durability, repairability, maintainability, upgradeability, and recyclability to address environmental sustainability issues in the healthcare domain. Achieving the design of Chloe SED® from a context-specific and circular economy approach revealed correlations between the material choice to manufacture the device, the device's initial cost, product durability and reuse cycle, reprocessing method and cost, and environmental impact. These correlations can be seen as interconnected conflicting or divergent trade-offs that need to be continually assessed to deliver a medical device that provides healthcare for all with limited environmental impact. The study findings are intended to be seen as efforts to make available medical devices to support women's access to reproductive health services.@en

Life cycle assessment (LCA) databases and software evolve. We analyzed to which extent software and evolving life cycle inventory databases affect the comparison of technology alternatives, using a comparative LCA on permanent magnets as a case study, with two selected software tools: CMLCA and Brightway LCA. We migrated the system models from the CMLCA to Brightway LCA software and alternated between the ecoinvent database versions 2.2 and 3.1 to 3.6 in the system background. When using ecoinvent v3.6 instead of v2.2, the change of the indicator results ranged from (Formula presented.) to 283%. The evolution of the ecoinvent database impacted the absolute amounts of the characterized results and the relative performance between alternatives. The impact category with the highest variability was ionizing radiation, which even showed a ranking inversion with ecoinvent v3.4. In contrast, the impact of using CMLCA or Brightway was negligible because the same data and modeling assumptions caused percentage differences below 0.4%. During the semi-automated data migration to Brightway, we identified 23 environmental flows in the CMLCA model that were not paired with their corresponding characterization factors in the published study of reference. This error had led to an underestimation of 63% in the photochemical oxidation indicator of one of the alternatives. This underestimation relates to an interoperability issue regarding the nomenclature of environmental flows in software alternatives and is a matter of data implementation rather than an issue intrinsic to the selected software. Finally, we identified improvement opportunities for the transparency and reusability of LCA models. This article met the requirements for a Gold-Gold JIE data openness badge described at http://jie.click/badges.

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Bio-based plastics are attracting increasing attention due to their perceived sustainability and circularity. While enabling circularity by using renewable feedstocks, they still contribute to plastic pollution. Furthermore, their rapidly growing market will cause bio-based plastics to constitute significant fractions of plastic waste, necessitating efficient recovery at end-of-life. Technical overviews of potential recovery pathways for bio-based plastics exist, although these have not yet been translated into product design recommendations. In this article, we assess the impact of material composition and product design on the feasibility of eight recovery pathways for bio-based plastics. The ability to recover a plastic not only depends on the plastic composition, but also on the way a product is designed. The alterations made to tailor plastics to be applied in products, and the product architecture, can enable or prohibit some recovery pathways. The outcomes highlight the importance of establishing a wider range of recovery pathways for plastics, and the crucial role of product design in enabling a circular economy for bio-based plastics. We also present a first guidance for product design to enhance the recovery of bio-based plastics.@en

Buildings are an important part of society's environmental impacts, both in the construction and in the use phase. As the energy performance of buildings improve, construction materials become more important as a cause of environmental impact. Less attention has been given to those materials. We explore, as an alternative for conventional buildings, the use of biobased materials and circular building practices. In addition to building design, we analyze the effect of urbanization. We assess the potential to close material cycles together with the material related impact, between 2018 and 2050 in the Netherlands. Our results show a limited potential to close material cycles until 2050, as a result of slow stock turnover and growth of the building stock. At present, end-of-life recycling rates are low, further limiting circularity. Primary material demand can be lowered when shifting toward biobased or circular construction. This shift also reduces material related carbon emissions. Large-scale implementation of biobased construction, however, drastically increases land area required for wood production. Material demand differs strongly spatially and depends on the degree of urbanization. Urbanization results in higher building replacement rates, but constructed dwellings are generally small compared to scenarios with more rural developments. The approach presented in this work can be used to analyze strategies aimed at closing material cycles in the building sector and lowering buildings' embodied environmental impact, at different spatial scales.

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This white paper presents 10 insights into the circular economy from the field of industrial ecology. Industrial ecology is a scientific field that takes a systems perspective to explore the society-wide use of materials and energy and address the related impacts on the natural environment. The circular economy is a framework for sustainable resource management that shapes government policy (McDowall et al. 2017), business model innovation (Lüdeke-Freund, Gold, and Bocken 2019) and public research agendas (Leipold et al. 2022).@en

Joey Nijnens holds a Master's degree in industrial ecology from Delft Technical University and Leiden University, as well as a Master's degree in supply chain management from Groningen University. He is employed at Monitor Deloitte as a strategy consultant, the strategy practice of Deloitte Consulting in the Netherlands, where he focuses on energy transition strategy and circular economy. Over the past years, his academic pursuits have centered around critical raw material supply, clean energy production dynamics, and clean energy supply chains. In his current role, he actively contributes to shaping national energy transition strategies and advancing clean energy investments. Paul Behrens (UK) is an author and associate professor at Leiden University. His research and writing on climate, energy, and food has appeared in outlets such as the BBC, Thomson Reuters, Politico, Nature Sustainability, Nature Energy, PNAS, Nature Food, and Nature Communications. His popular science book, “The Best of Times, The Worst of Times: Futures from the Frontiers of Climate Science” (Indigo Press, 2021) describes humanity's current trajectory and possible futures in paired chapters of pessimism and hope. Paul won International Champion in the Frontiers Planet Prize and the Falling Walls Prize in 2023. Oscar Kraan is a senior manager at Monitor Deloitte, the strategy practice of Deloitte Consulting in the Netherlands. He has more than 10 years of experience supporting governments and companies in the energy sector navigate the future of energy. Since 2018, Oscar has been part of Deloitte, where he focuses on developing decarbonization strategies and supporting the development of the hydrogen market. He co-leads Deloitte's Global Hydrogen Center of Excellence and the Future of Energy practice within Deloitte. In his work at Deloitte, he continues to be involved in scientific research around energy system integration, wherein he combines scientific insights with policy and business challenges. Before Deloitte, Oscar obtained his PhD on the topic of energy transition scenarios, wherein he applied agent-based modeling to energy and electricity system modeling. Before and during his PhD, Oscar worked 6 years with Shell's Scenario Team and Shell's New Energies Strategy Team. Benjamin Sprecher is an assistant professor of circular product design at the Delft Technical University. His main research interests are sustainable design, quantification of environmental impacts, and industrial ecology. His current work explores how quantification of environmental impacts can inform sustainable and circular design and how decisions at the product design level relate to system-level concepts such as circular economy. His PhD and postdoc were focused on critical raw materials and supply chain resilience, and he remains working on these topics, as well. René Kleijn is a professor of resilient resource supply at Leiden University in the Netherlands. He serves as the department head of the industrial ecology group at Leiden University and the scientific lead of the Circular Industries Hub at the Leiden-Delft-Erasmus Centre for Sustainability. His research primarily centers on sustainability matters, employing quantitative methods like life cycle assessment and substance and material flow analysis. Kleijn's expertise extends across various industries, including chemicals, energy, and recycling, where he effectively applies these methodologies to address environmental challenges. He has actively participated in numerous large consortia as part of EU-funded research projects. In recent years, his research has focused on critical raw materials, resilient supply chains, circularity, and material constraints within the evolving landscape of the energy transition.

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The European Union (EU) has set a 37.5% GHG reduction target in 2030 for the mobility sector, relative to 1990 levels. This requires increasing the share of zero-emission passenger vehicles, mainly in the form of electric vehicles (EVs). This study calculates future GHG emissions related to passenger vehicle manufacturing and use based on stated policy goals of EU Member States for EV promotion. Under these policies, by 2040 the stock of EVs would be about 73 times larger than those of 2020, contributing to a cumulative in-use emission reduction of 2.0 gigatons CO2-eq. Nevertheless, this stated EV adoption will not be sufficiently fast to reach the EU's GHG reduction targets, and some of the GHG environmental burdens may be shifted to the EV battery manufacturing countries. To achieve the 2030 reduction targets, the EU as a whole needs to accelerate the phase-out of internal combustion engine vehicles and transit to e-mobility at the pace of the most ambitious Member States, such that EVs can comprise at least 55% of the EU passenger vehicle fleet in 2030. An accelerated decarbonization of the electricity system will become the most critical prerequisite for minimizing GHG emissions from both EV manufacturing and in-use stages.

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The world is facing a growing neodymium demand, creating the need for developing a recycling system to handle future waste flows. Recycling technologies are emerging, but the recycling system around them can only be established with knowledge about available end-of-life (EoL) products. Therefore, this study quantified neodymium waste in European countries using material flow analysis, and assessed the recyclability of major EoL products. For 2019, we find a waste flow of 7.7 kt Nd, consisting mostly of NdFeB magnets. HDDs represent a large current waste flow, while the demand for magnets in industrial applications is increasing. In the future, electric vehicle motors and wind turbines likely provide a source of neodymium with good recyclability. Consequently, there will be different product groups that determine the future waste volumes. To manage the changing waste flows, a neodymium recycling system should be developed with the product properties of future waste flows in mind. Meanwhile, the recyclability of products can be improved by addressing bottlenecks in the recycling chain.@en

This design review evaluates the use of bio-based plastics in durable consumer products. The main question is: how does the use of bio-based plastics influence the product’s design, functionality, marketing & communication, and sustainability? Although higher material prices would lead one to expect that higher value applications would be targeted, research shows bio-based plastics are mainly used in short-lived applications like packaging. This study investigates their use in durable consumer products through a design review. The results indicate that bio-based plastic usage is still in its early days in durable products. Bio-based plastics appear to be utilized as straightforward replacement of fossil-based plastic. Designers are not yet using the unique properties of bio-based plastics in the design of their products. Companies mainly exploit the green image of bio-based plastics in their marketing & communication. Their focus is on the renewable feedstock and not on sourcing, or on recovery at end-of-life.@en

To achieve climate neutrality, future urban heating systems will need to use a variety of low-carbon heating technologies. The transition toward low-carbon heating technologies necessitates a complete restructuring of the heating system, with significant associated material requirements. However, little research has been done into the quantity and environmental impact of the required materials for this system change. We analyzed the material demand and the environmental impact of the transition toward low-carbon heating in the Netherlands across three scenarios based on the local availability and capacity for sources of low-carbon heat. A wide range of materials are included, covering aggregates, construction materials, metals, plastics, and critical materials. We find that while the Dutch policy goal of reducing GHG emissions by 90% before 2050 can be achieved if only direct emissions from the heating system are considered, this is no longer the case when the cradle-to-gate emissions from the additional materials, especially insulation materials, are taken into account. The implementation of these technologies will require 59-63 megatons of materials in the period of 2021-2050, leading to a maximum reduction of 62%.

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