Discussion

To support more effective plastic governance, we identify four strategic action areas that respond to the identified KGs, these include (1) knowledge generation, (2) methodological development, (3) transparency and disclosure, and (4) tracking and traceability. These were derived through an iterative clustering of KGs based on their shared implications for governance and the types of interventions required to address them (see STAR Methods). As such, they represent categories of intervention required to address how KGs constrain effective plastic governance in the EU.

Table 1 outlines each strategic action area, provides a brief description, and indicates the primary KGs targeted. Some KGs are present across multiple strategic action areas. This overlap reflects the cross-cutting nature of plastic governance, where individual KGs can require multiple types of action. For example, the KG related to chemical recycling of plastics cannot be addressed through knowledge generation alone but also hinges on greater transparency and disclosure to make existing knowledge accessible for decision makers. The strategic action areas discussed here are not intended as a comprehensive policy blueprint. Rather, they highlight enabling conditions that repeatedly emerged as necessary for addressing the identified KGs and enhancing plastic governance interventions in the EU.

Strategic action area | Description | Primary KGs addressed
Knowledge generation | generate new empirical evidence to fill critical gaps and determine thresholds | KG1.1 sustainable levels of productionKG3.3 chemical recyclingKG3.4 remediation of plastic pollutionKG4.1 micro(nano)plasticsKG4.2 hazard and exposureKG4.4 social cost of plastics
Methodological development | develop standardized, replicable, and actionable methodologies | KG1.2 material substitution and problem shiftingKG2.1 plastic waste prevention effortsKG2.2 essential useKG3.1 plastic waste volumesKG4.1 micro(nano)plasticsKG4.2 hazard and exposure
Transparency and disclosure | implement mandatory reporting systems and expand disclosure requirements | KG1.3 chemical compositionKG3.2 recycling outcomesKG3.3 chemical recyclingKG4.3 plastic trade flowsKG4.4 social cost of plastics
Tracking and traceability | develop systems to monitor material flows and establish product tracking mechanisms | KG1.3 chemical compositionKG2.1 plastic waste prevention effortsKG3.2 recycling outcomesKG4.3 plastic trade flows

A key insight from this analysis is that while generating new evidence through research is essential in several areas, many of the identified gaps persist due to limitations in data accessibility, lack of standardized methodologies, insufficient transparency, and weak systems for tracking material flows. The strategic action areas therefore reflect the need for a broader set of governance and infrastructure interventions beyond further research, which could all merit attention in the upcoming EU Circular Economy Act, which is currently under preparation.94

Knowledge generation

Fundamental uncertainties exist regarding the effects and costs associated with the ubiquity of plastics in contemporary society. These are evident in the KGs related to chemical and particle hazards (hazard and exposure), social costs (social cost of plastics), and the sources, behavior, and impacts of micro(nano)plastics (micro(nano)plastics), all reflecting limitations in current understanding of harms posed by the plastic system. In parallel, there is uncertainty regarding sustainable levels of plastic production (sustainable levels of production), reflecting limited knowledge about the thresholds we should strive for. Meanwhile, technologies, such as chemical recycling and pollution remediation (remediation of plastic pollution), are developing and being supported despite limited understanding of their real-world performance, environmental trade-offs, or long-term consequences. All these topics points toward possible future research priorities to be emphasized in the upcoming revision of the European Framework Programme (FP10).95

A common denominator across these KGs is the limited availability of empirical evidence, which constrains the ability to assess harms, thresholds, and trade-offs. Addressing this limitation is closely tied to the involvement of a broad range of actors, including research institutions and research funders such as public agencies, foundations and the private sector. Universities and research institutions are likely to play a critical role, particularly in advancing fundamental understandings of plastics’ impacts and sustainable alternatives.

When it comes to the assessment of chemical hazards, the challenge is to undertake systematic, large-scale, and sustained research efforts. This calls for dedicated investment to enable hazard assessments of all chemicals used in plastic production, work often outside the scope of traditional academic funding geared toward novelty, but which, nonetheless, is essential for more informed governance.96 Given the scale and complexity of this task, strategic prioritization of research is warranted. In particular, focusing on hazard identification rather than full exposure characterization is appropriate in contexts where full risk-based assessments are unlikely to be feasible.97 At the same time, the scale and complexity of such assessments should be reduced through “chemical simplification”, both by reducing the number of chemicals used and molecular complexity and by applying grouping approaches that help avoid regrettable substitutions.98 While the importance of this was explicitly acknowledged in the EU Chemicals Strategy for Sustainability,39 and the European Chemicals Agency has moved to adopt grouping approaches to assessment of chemicals,99 the recent decision to abandon a revision of the Registration, Evaluation, Authorization, and Restriction of Chemicals (REACH) regulation raises significant questions regarding future opportunities to not just assess but also regulate chemicals by groups, for example, regarding bisphenols.100

Similar challenges arise in the context of recycled plastics, where heterogeneous and insufficiently characterized material streams make comprehensive hazard assessments particularly difficult. Here, governance efforts may be better directed toward stricter material control, such as closed-loop systems or targeted use restrictions.101,102

While these gaps highlight the need for continued investment in research, scientific uncertainty should not be used as a justification for delaying policy action. A substantial body of research shows that uncertainty has historically been mobilized as a deliberate delay tactic by industry actors, whereby scientific doubt is amplified to postpone regulation despite accumulating evidence of harm.103,104 Similar strategies have been documented across environmental domains, including plastic pollution. In such cases, calls for additional research are used to defer decisions and weaken regulatory ambition.105,106 The framing and mobilization of KGs are, thus, shaped by the diverse objectives of stakeholders, some of which may conflict with climate, environmental, and public health goals.107,108 This underscores the importance of strategies to identify and manage conflicts of interest. Recent analyses of the global plastic treaty negotiations underline the urgency of this concern. These studies argue that entrenched axes of power exist, whereby petrostates and certain industry interests act to retain or expand economic and political power and to sustain profits across petrochemical plastic supply chains. These interests are, for instance, advanced through the strong presence of industry representatives at the negotiations and, in some cases, within state delegations, pushing for weakened treaty ambition.105,109,110 The dynamics provide critical context for interpreting the KGs identified through the expert workshop, highlighting that their resolution depends not only on research capacity, but also on the institutional and regulatory conditions that shape how knowledge is generated, standardized, disclosed, and used in decision-making. An issue was taken up in the following action areas on methodological development, transparency and disclosure, and tracking and traceability.

Methodological development

Several identified KGs highlight the importance of developing standardized methodologies capable of generating consistent, comparable data to support evidence-based decision-making. Developing robust approaches to assess the essentiality of plastics in different contexts (Essential plastic use) is critical. While the concept of essential use was introduced in the EU Chemicals Strategy for Sustainability39 and further elaborated by the Commission,40 its continued implementation (including potential expansion from chemicals to plastic products) is uncertain following the abandoned REACH revision. Equally important is advancing techniques to detect and quantify nanoplastics (micro(nano)plastics) and their toxicity (hazard and exposure), without which, it is not possible to accurately assess associated hazards. Similarly, evaluating whether material substitution leads to genuine environmental advantages (material substitution and problem shifting) would benefit from standardized methods. In the context of EU policymaking, the recent decision to cancel negotiations regarding the Green Claims Directive,111 arguably represents a step backwards in terms of establishing such standardized methods for evaluating environmental benefits.

Improved methodologies for monitoring progress toward political targets are essential for translating political ambitions into action. Without such tools, it is difficult to credibly inform and support policy target setting or expect meaningful alignment from industry and other stakeholders. For example, when the political ambition in the EU is to increase plastic circularity,112 existing methods for quantifying plastic waste must be expanded to account for plastics present in non-packaging and residual waste streams (KG 3.1). Without better waste accounting, both the full scale of the problem and potential progress toward greater circularity remain obscured, as it is not possible to accurately diagnose waste generation or verify whether interventions are delivering real improvements. Similarly, if the political ambition is to prioritize higher value strategies within the waste hierarchy, such as reuse, which extends products’ lifespans, we need to develop a standardized methodology for reporting on reuse so that efforts can be incentivized, recognized, and rewarded (plastic waste prevention efforts). For packaging, a similar ambition is articulated in the EU Packaging and Packaging Waste Regulation,113 but the actual development of standardized methodologies is still to be finalized and is expected in future implementing acts. Across the EU, there are examples of member states, regions, and cities experimenting with reuse or preparing for reuse targets, but the lack of a standardized methodology hampers data comparability, limiting the ability to benchmark performance and identify best practice.114

Transparency and disclosure

Lack of transparency underlies several KGs. Notably, there is insufficient disclosure of the chemical composition of plastics (chemical composition), which hampers hazard assessments across the value chain. The systemic opacity of plastic trade (plastic trade flows) raises multiple questions, such as whether current recycling practices support intended climate and environmental goals (recycling outcomes). Similarly, there is limited public access to industry claims in the chemical recycling sector (chemical recycling) Although the recently approved EU-implementing act on mass-balance accounting seeks to strengthen auditability,115 questions remain regarding public transparency and access to underlying data, and the legislation has been met with sharply divergent reactions. In addition, public subsidies to plastic production remain largely opaque, despite being one of the more readily quantifiable components of the social cost of plastics (social cost of plastics). These KGs are fundamentally about making existing and new information publicly accessible to enable informed decision-making, consistent with the objectives of the Aarhus Convention, to which all EU member states are parties.116

On the topic of trade, regulations under the Basel Convention, including its 2021 Plastic Waste Amendments, formally establish transparency and control requirements for plastic waste exports.117 However, inconsistent implementation and regulatory loopholes, such as legacy classifications that omit “hidden” plastics in textiles or synthetic rubbers, often undermine these measures, preventing comprehensive traceability and public access to reliable data on the movement and management of exported plastic waste.43,117,118 Addressing these shortcomings requires stronger regulation, for instance, an expansion of the basel prior informed consent procedure to include all plastic waste, also the hidden, and currently unregulated, categories. Moreover, improving the harmonized commodity description and coding system (HS) that classifies trade flows according to the function of goods rather than the goods’ materials could improve our understanding of the movement of plastics across the globe.82 This could result in more effective efforts aimed at governing flows of plastics, for example, more effective regulation avoiding increased exports of plastics to countries with less well-functioning waste handling systems. Beyond regulatory disclosure, tackling KGs related to illegal trade of plastic waste requires targeted law enforcement and improved international coordination. While commercial interests and administrative burdens should be considered, stronger regulatory intervention is necessary to address persistent enforcement failures.118,119 A recent revision to the EU Regulation on Waste Shipments120 seeks to address this challenge through a ban on exporting non-hazardous plastic waste to countries that are not members of the Organisation for Economic Co-operation and Development (OECD) and the establishment of an enforcement group targeting illegal waste shipments by the European Anti-Fraud Office.121

In the case of chemical recycling, a complementary strategy is to make public access to verifiable evidence on environmental and climate impacts, as well as technical and economic feasibility, a guiding criterion for future public investment. Transparency could be treated as a precondition for public funding.

Tracking and traceability

Several of the KGs highlight the importance of strengthening and expanding tracking and traceability across the plastic system. We lack insight into how plastics move through the economy (plastic trade flows); it is often impossible to determine what plastics are made of or contain (chemical composition); we have limited knowledge of where plastics have been used and for how long (plastic waste prevention efforts); and we do not know what happens to a lot of plastic waste once sent for treatment (recycling outcomes).

Faced with these challenges, there is a growing need to develop traceability tools that better support plastic supply-chain governance by making information accessible about products’ origin, material composition, and end-of-life handling.122,123 Different types of traceability innovations are emerging, drawing on both digital and physical technologies,124 yet their future development and implementation must overcome significant practical, technical, and political barriers. This creates scope for policy support, including targeted funding and the development of shared data standards.122 In the EU context, digital product passports (DPPs) are being introduced for selected priority product groups under the Ecodesign for Sustainable Products Regulation,125 including information on products with substances of concern with a negative influence on reuse or recycling. A DPP is a digital record that compiles key information about a product within a defined scope, governed by agreed access and data-management rules and accessed electronically via a unique identifier.126 While DPPs are currently being developed for products such as textiles, furniture, tyres, mattresses,127 and other plastic products, such as packaging where volumes are high, product lifetimes short, and contributions to plastic pollution are substantial, other approaches than DPP may be more practical or effective, reinforcing this as a strategic action area requiring further attention.

While traceability tools such as DPP primarily focus on individual products and supply chains, more effective governance of plastic will also require system-level tracking. It is necessary to enhance and harmonize statistical reporting on plastics, including data on production volumes, the quantity and types of plastic-containing products placed on the market, trade flows, and waste management practices. Current work to implement common end-of-waste criteria across the EU countries is one step toward allowing such harmonization.128 Improved tracking and disclosure mechanisms could support transparent monitoring and enable better policy design, enforcement, and public accountability throughout the plastics system.129

Next steps for plastic governance

Together, our analysis highlights that plastic pollution is a complex, systemic challenge with profound consequences for human health and the environment. While the ongoing treaty negotiations represent a critical opportunity for global action, progress is restrained by the current political deadlock. However, the ability to effectively govern plastics is also constrained by a range of KGs, creating a scope for action both in preparation for future treaty negotiations as well as outside treaty negotiations.

Focusing on the context of the EU, this paper has analyzed critical KGs that impede effective plastic governance across the full life cycle of plastics. Our analysis shows that plastic governance is constrained not only by missing evidence but by systemic deficiencies in how knowledge is generated, standardized, disclosed, and monitored across the plastics’ life cycle, underscoring that addressing KGs requires governance and infrastructure interventions alongside further research. Based on the analysis, we identify four strategic action areas: (1) knowledge generation, (2) methodological development, (3) transparency and disclosure, and (4) tracking and traceability. Coordinated efforts across these areas will be key to enabling sustainable, systemic solutions to the complex challenges posed by plastic pollution.

The EU has greater scope to act in some areas, such as developing methodologies, generating new knowledge, and implementing traceability systems. Other areas, particularly those that require international coordination, such as changes to the Basel Convention, are more challenging and depend on multilateral engagement and the current geopolitical landscape.

While we recognize the difficulty of achieving an ambitious treaty, our analysis demonstrates that meaningful progress can still be made within the EU. Pursuing these strategic action areas strengthens the legitimacy of the EU’s ambition to achieve an international agreement that addresses the entire plastic life cycle; it supports more effective plastic governance and provides a foundation to inform and advance future international negotiations.

Limitations of the study

This study has several limitations. First, the identification and prioritization of KGs were informed by a structured expert consultation and subsequent author-led analysis, meaning that the findings inevitably reflect the expertise, perspectives, and institutional backgrounds represented in the workshop and subsequent process. Although contributors came from diverse disciplinary and organizational contexts, other expert communities may have emphasized different KGs or governance priorities. Second, the literature analysis was conducted through an expert-informed and purposive review rather than a formal systematic review, prioritizing breadth, policy relevance, and emerging evidence over full reproducibility. Third, the analysis focuses on the EU as a governance context. While many of the identified KGs are relevant also outside the EU, the salience of specific gaps and the feasibility of proposed action areas may differ across regions with different institutional capacities, regulatory traditions, and socioeconomic conditions.