Identifying and overcoming social-ecological barriers to ending plastics pollution

Plastics are deeply embedded in contemporary life, and their production and pollution contribute to irreversible harm across ecological and social systems. Recognized as a “novel entity” in the Planetary Boundaries framework, plastics challenge traditional governance models due to their chemical complexity and diversity, cross-sectoral impacts, and pushback from powerful political and economic actors. This study addresses urgent science-policy gaps through a structured expert elicitation, conducted during the ongoing negotiations on the global plastics treaty. We present the Experts Multi-Issue Knowledge Elicitation (EMIKE) method - a flexible, co-productive approach that addresses social-ecological dimensions of plastics pollution. Through a three-phase process involving 21 interdisciplinary experts, we identified 21 critical issue areas spanning toxic chemical use, social inequality, overconsumption, climate impacts, and financing and policy incoherence, among others. The EMIKE process generated a matrix of interrelated indicators across plastics’ life cycle to inform adaptive, more comprehensive, just, and evidence-based policymaking. EMIKE offers a methodology for surfacing often neglected issues in natural science driven studies, fostering interdisciplinary dialogue, and advancing policy-relevant knowledge. It enables structured elicitation - attuned to power, uncertainty, and evolving political contexts - to better integrate diverse science inputs into global governance. This approach is essential not only for plastics governance, but also for any multifaceted sustainability issue requiring intersectional, systems-based solutions. Key findings highlight the inseparability of ecological and social concerns, the limits of technocratic quantification, and the need to democratize science-policy interfaces. Experts emphasized the importance of precautionary action, transparency, and justice-based governance to counteract corporate influence and systemic inertia. Our study also illustrates how scientific frameworks can support policy development by adequately considering the complexity of global sustainability challenges.