Environmentally extended multi-regional input–output (EEMRIO) analysis provides a robust methodology for assessing economic, social, and environmental footprints across nations and regions. Increasing its geographical resolution is essential for addressing local environmental issues and informing targeted policy decisions. While subnational EEMRIOs ideally rely on survey data, such data are often unavailable or resource-intensive to process. As a result, partitioners resort to proxies and algorithms. Yet, the transparency of these algorithms and the underlying data are often suboptimal. Here, we present a novel, open-source, top-down regionalization approach applicable to any EEMRIO database. Our method builds on location quotients (LQ), extending their application to a multi-regional framework. This extension ensures calculations remain traceable, eliminates the need for supplemental balancing procedures, and requires minimal, readily available additional proxy data, making it highly accessible for practitioners. Using European steel trade as a proof-of-concept, we demonstrate how this approach assesses local impacts, highlights local–global trade interactions, and identifies opportunities that national IO data often obscure.

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.

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.

With initiatives such as the European Green Deal establishing more stringent environmental requirements, there is an increasing need to develop aircraft technologies and sustainable aviation practices with reduced climate impacts. Additionally, conventional environmental Life Cycle Assessments (LCAs) often struggle to capture the dynamic and complex nature of aircraft operations; in particular, non-CO₂ in-flight impacts, which contribute significantly to climate change, are often overlooked. In this study, we improve a discrete-event LCA approach with a climate impact evaluation model and apply it to scenario analyses comparing different aircraft designs, fuel types, and flight schedules. Our findings reveal that, contrary to previous LCA studies, the climate impact per kilometre flown increases with longer flight distances and that an efficiently planned flight schedule can reduce the overall environmental impact. The study highlights the necessity of incorporating non-CO₂ effects and operational scenarios into LCA to achieve a more accurate understanding of aviation's environmental impact.

The supply of critical raw materials, especially titanium, poses a significant challenge for the aviation sector. Increased circularity is often proposed as a solution by industry and policymakers. However, the effects of circular strategies remain insufficiently understood. Therefore, this paper analyses different circular strategies, namely recycling, a pure lifetime extension, and an enhanced lifetime extension that includes an engine aircraft, based on real-world data up to the year 2040. The findings indicate that recycling retired aircraft only marginally affects the required rising inflow of titanium by less than 5%. The engine upgrade strategy shows similar results. In contrast, a pure lifetime extension shows the greatest potential for mitigating supply constraints and can be further enhanced to a potential of more than 10% when combined with recycling. The results highlight the complexity of circular strategies and emphasise a stronger focus on lifetime extension for the aviation sector and other industrial sectors.

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.

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.

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.

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.

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.

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.

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.

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.

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.