While it is vital to agree to a set of global objectives and targets to reduce plastic pollution as part of the Global Plastic Treaty, past negotiations have been troubled by differences in regional and national priorities and needs. To take these different priorities and needs into account, this letter proposes the adoption of an interdisciplinary source-to-sea approach. A source-to-sea approach emphasizes the connected nature between land-based sources of marine plastic pollution along the life cycle of plastic products on the one hand, and air, soil, and water cycles that determine marine plastic flows and associated sustainability risks on the other hand. It takes into account how we know more about the way in which production, use and plastic waste contribute to the pollution of rivers and seas in one location (e.g. in Europe), than we do for rivers and seas in other places (e.g. Africa). There are also regional and national differences in how much awareness exist about plastic pollution and how it is governed and regulated. These differences translate in different priorities and needs in terms of how to most efficiently and effectively reduce plastic pollution. The letter argues that these differences should be embraced and that an interdisciplinary source-to-sea approach can help to develop tailor-made regional and national targets and measures that in turn contribute to achieving the global ambitions of the Global Plastic Treaty. A key role is foreseen for existing governance institutions, such as river basin commissions and regional seas conventions (coordinated by UNEP Regional seas Programme), while the Global Plastic Treaty can become a platform for sharing of approaches, lessons and strategies between regions and countries so that over time, plastic pollution will be reduced worldwide.

Indigenous Peoples are disproportionately impacted at every stage of the plastic lifecycle, from the extraction of the fossil fuel feedstock and plastic production, to the widespread dispersal of maco-, micro- and nanoplastics in the natural environment. They face many barriers to their participation in UN processes and must constantly push for their rights to be upheld and for their full and effective participation to be secured. This constant basic struggle for Indigenous rights and participation can consume all the energy and efforts of Indigenous delegates in UN processes at the expense of all the other important knowledge and messages they carry from their communities and nations to address the very real and serious harms that have been inflicted on their territories and all the life within it. Negotiators at INC-5.2 have a great responsibility to address this serious global crisis, while being reminded that Indigenous Peoples, who are on the frontlines of the plastic pollution crisis, must be equal participants as experts of their own knowledge and science and participate in the process as rightsholders in all decision-making that affects them.

The Intergovernmental Negotiating Committee (INC) on plastic pollution are United Nations member states who will convene for the second part of the fifth session of the Intergovernmental Negotiating Committee in Geneva (INC5.2) 5-14 August, 2025 to negotiate a global plastics treaty. The Scientists’ Coalition for an Effective Plastics Treaty (‘The Scientists’ Coalition’) is an international network of independent scientific and technical experts who have been contributing robust science to treaty negotiators since INC1 in 2022. The Scientists’ Coalition established a series of working groups following INC5.1 in Busan, Korea 25 November – 1 December 2024. Each working group has produced science-based responses to the selected articles of ‘the Chair’s text’ (the latest version of the draft global plastics treaty text). This Letter to the Editor summarises those responses.

This letter discusses the complex nature of plastics, why regulating plastics is a ‘wicked problem’, and the implications of a life cycle approach. The draft Global Plastics Treaty attempts to address two key problems: the cap on production and the problem of chemical additives in plastics. As a ‘wicked’ problem with many conflicting interests, dealing with plastics requires a holistic life cycle approach completely different from the Montreal Protocol. Strict and enforced limits on polymer production would reduce plastics pollution and also encourage a reduction in the range of additives, as limiting production would make mechanical or chemical recycling more viable. Used plastics need to be turned into a commodity rather than a waste, and reducing and standardising the number of different chemical formulations would help by reducing the number of chemicals to be regulated. To achieve these objectives, this letter argues for a regulatory approach based on a forensic analysis that applies extended environmental systems analysis to all the life cycle stages of the plastics value chain.

This letter to the editor explores the importance of a just transition for waste pickers in the context of the global plastics treaty. It sets out ideas for just transition at the level of production reduction, replacements and substitutes, systems change and waste management.

This article challenges the OECD’s dominant downstream-centric framework on plastic pollution by drawing on long-term ethnographic fieldwork in India, Indonesia and the Philippines. While OECD policies emphasize mismanaged waste and littering in low- and middle-income countries as primary causes of plastic leakage, the authors argue this perspective obscures the structural role of upstream plastic production, driven largely by petrochemical interests in the Global North. Through field data, the article reveals how “leaky” infrastructures – such as incineration plants in India, public–private waste partnerships in Indonesia and grassroots upcycling in the Philippines – fail to contain plastic waste, often exacerbating pollution and exposing communities to toxic emissions and microplastics. The study introduces a conceptual framework of “material and structural leakiness,” emphasizing how plastics and the infrastructures designed to manage them are inherently porous. It critiques the notion of shared responsibility, highlighting how it disproportionately burdens marginalized communities. The authors call for a paradigm shift away from recycling and clean-up as core solutions, advocating instead for upstream interventions like production caps and chemical regulation. The article underscores that without legally binding global commitments to reduce virgin plastic production, the toxic burden of plastic pollution will continue to fall on the most vulnerable populations.

As governments prepare for the resumed session of the Intergovernmental Negotiating Committee on Plastic Pollution (INC-5.2), the urgency of agreeing on a legally binding global plastics treaty is more pressing than ever. This editorial introduces a collection of letters calling for systemic, science-based, and justice-oriented approaches to plastic governance delivered through an ambitious and effective global plastics treaty. The letters span environmental, health, and social disciplines, and highlight the shortcomings of fragmented policy and assert the need for coordinated and binding action. The letters advocate for reducing plastic production, implementing restrictions on toxic chemicals, incorporating the structural inclusion of affected communities, and ensuring robust scientific oversight. Taken together, the collection of letters reflects the scientific and ethical imperatives to act decisively in shaping a transformative and enforceable plastics treaty.

An effective and just Financial Mechanism will be crucial to the success of the Global Plastic Treaty. The content in the latest Chair’s Text from INC-5.1 on finance (primarily in Article 11) could be strengthened to avoid replicating shortcomings in existing financing models, which have often been insufficient and have not always provided the necessary resources for global sustainable development. Experiences with climate finance mechanisms reveal a pattern of misdesign that needs to be addressed. The current Article 11 reflects the deep divisions evident in the two main proposals tabled at INC-5.1 in November 2024. In the light of past precedents and tensions, we argue that several core design principles related to scope, scale and social and health considerations could ensure that the Global Plastics Treaty’s Financial Mechanism supports just, ambitious and transformative global action on plastic pollution. Furthermore, we argue that several elements in the current treaty text may undermine the design and implementation of an effective and just Financial Mechanism for the future Global Plastics Treaty. These risks include overemphasizing waste management; missing connections between finance and other measures in the treaty; risks of not addressing the most effective responses; not adequately addressing plastic leakage, releases and emissions; sustaining financial investments in techno-economic lock-ins lacking sufficient safety and sustainability criteria, standards and monitoring requirements and the prospect of plastic credits, which risks repeating past false solutions. There is an opportunity for the treaty to overcome these challenges with a financial mechanism that addresses overproduction and incentivizes safer, more sustainable, accessible and cost-effective upstream solutions.

Rivers act as long-term plastic storage and a pathway for land-based plastic pollution into the ocean. Monitoring river plastic at a global scale remains challenging, with only limited large-scale and long-term monitoring efforts to date. Citizen science approaches may ensure a more continuous basic knowledge of plastic pollution in rivers, which can be used to assess the efficacy of reduction measures. We evaluated the suitability of several river plastic monitoring methods for citizen science, through field monitoring and a subsequent survey with citizen scientists in Accra, Ghana. Four measurement techniques (visual counting, macroplastic net sampling, microplastic net sampling and hydrometric measurements) were tested in the field and evaluated by citizen scientists. The visual counting method, used to estimate floating macroplastic transport, emerged as the most promising method for citizen science–based river plastic monitoring. Using the data collected by citizens, we quantify the variability in transport and concentration of both macroplastic and microplastic.

Plastics have come to symbolize the lifestyle and technological advancements of the 20th century, representing modern convenience and progress. In recent years, global plastic production surpassed 360 million tons in 2018 and is projected to reach between 500 and 600 million metric tons by 2025. This plastic accumulates as waste in freshwater, marine and land environments, leading to habitat disruption, alterations in nutrient cycles and harm to wildlife through exposure to toxic substances, entanglement and ingestion which pose significant ecological and health risks. The long-term ecological changes resulting from this pollution are likely irreversible. Developing countries in the Global South, including Bangladesh, are particularly vulnerable to the challenges of poorly managed plastic waste due to a lack of institutional, financial and technical resources to combat plastic pollution. The Aquatic Zoology Research Group has focused on addressing plastic pollution in Bangladesh and adopted a comprehensive strategy to tackle plastic pollution, starting with identifying the issue through various methods, followed by a thorough assessment of the plastic pollution situation and finally proposing solutions for mitigation. Our review of the current state of plastic pollution in Bangladesh’s aquatic systems highlighted significant research gaps, despite the country’s early ban on plastic bags. As a conservation research team from a developing nation facing the severe impacts of plastic pollution, we studied and listed specific expectations for the upcoming INC 5.2 meeting, highlighting challenges faced by many similar countries. We hope that INC 5.2 will move beyond mere statements to implement concrete and equitable actions.