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Introduction

ORGANIZATION OF THE WORKSHOP AND PROCEEDINGS

The National Academies hosted the workshop Circularity and Plastics on May 13–14, 2025, at the National Academy of Sciences building in Washington, DC, and virtually. The workshop was held under the auspices of the Roundtable on Plastics. The Roundtable on Plastics was formed to build upon recent works of the National Academies including the 2023 and 2021 reports Repurposing Plastic Waste in Infrastructure and Reckoning with the U.S. Role in Global Ocean Plastic Waste, and two workshops held in 2020 Closing the Loop on the Plastic Dilemma: Proceedings of a Workshop in Brief and Environmental Health Effects of Microplastics: Proceedings of a Workshop in Brief. The Circularity and Plastics workshop was organized by a planning committee of Roundtable members tasked with designing the agenda (see Appendix A) and identifying speakers (see Box 1-1). Over the course of two days, cross-sectoral participants engaged with invited speakers in panel sessions and with each other in breakout and small-group discussions focused on three major plastics use sectors with high production and waste volumes: packaging, textiles, and building materials (see Appendix B for an overview of existing policies in support of circularity within these sectors). The groups explored possible solutions and strategies within and across sectors including rethinking, redesign, and reuse to minimize plastic waste and the associated effects on human and environmental health.

A keynote address on principles of circularity was followed by a panel on cross-sectoral perspectives of circularity to set the stage for later discussions and provide a basis for understanding differing views and approaches. Next, workshop participants heard from speakers representing each of the three use sectors who described the state of circularity and challenges and opportunities therein, with a final panel discussion on cross-sectoral synergies and interdependencies. Participants were then invited to join

breakout sessions by use sector to discuss the desired future state and propose pathways to achieve that future state.

This proceedings summarizes the workshop discussions and is organized to reflect the use sectors and interdependencies explored over the two days. Chapter 2 provides an overview of the panel discussions on circularity, current state of plastics in the use sectors, and sectoral interdependencies. Chapters 3, 4, and 5 explore solutions for packaging, textiles, and building materials, respectively. Chapter 6 summarizes synergies and interdependencies in the solutions discussed and how the approaches could be integrated. Box 1-2 provides definitions of some key terms used throughout the workshop. This proceedings has been prepared by the workshop rapporteurs as a factual summary of what occurred at the workshop. The planning committee’s role was limited to planning and convening the workshop. The views contained in the proceedings are those of individual workshop participants and do not necessarily represent the views of all workshop participants, the planning committee, or the National Academies of Sciences, Engineering, and Medicine.

KEYNOTE ADDRESS

In a keynote address, Danielle Holly, Lead, North America at the Ellen MacArthur Foundation (EMF), set the stage for workshop discussions about solutions and provided background on EMF’s efforts during the past 15 years to accelerate the transition to a circular economy. Toward that end, EMF has employed three key strategies:

• Develop and promote the idea of the circular economy with thought leadership and research work

• Engage and inspire key actors in business and policy to create systems change
• Mobilize systems solutions at scale

Holly addressed the fundamentals of a circular economy, highlighting the wasteful nature of the current “linear” economic system, where resources are extracted from the ground, products are made and used for an increasingly short period of time (e.g., food systems, textiles, materials in the built environment), and ultimately end up in landfills.

The aspiration and principles of a circular economy are to (1) prevent the production of waste and pollution, (2) circulate products and materials at their highest and best use, and (3) regenerate natural systems. Holly emphasized that these three principles of circularity should be integrated into the design phase of products and systems, as well as the mindsets of individuals in various institutions, businesses, and government bodies. In a circular system, a product is made with the intent of circularity, such that reuse, repair, refurbishment, remanufacturing, and/or repurposing (Re-X models) are built in at the start, thereby removing current obstacles.

Holly described the benefits of the circular economy, stating that the current linear approach is designed for economic growth and profit, but, like any system optimized for only one dimension, it is not sustainable. She emphasized there is potential for sustainable growth in the circular economy, within the planetary boundaries, and significant economic opportunity (on the order of $1 trillion dollars) that will grow with scale and supportive policy (Ellen MacArthur Foundation, 2014). In addition, Holly noted that circularity pushes resilience into supply chains and increases material security, thereby addressing some current geopolitical concerns while tackling 45 percent of the greenhouse gas emissions generated outside of the energy economy (Ellen MacArthur Foundation, 2019). She added that minimizing or eliminating the waste of products and foods that are used and discarded could meet half of global non-energy climate goals.

Holly next described the momentum toward building a circular economy in the 15 years since EMF’s founding, noting that more than half of businesses have circular economy targets, more than 80 countries have circular economy roadmaps, and more than 200 higher education institutions cover circular economy in their core curriculum. She expressed that, in a new and fundamental shift, circular economy concepts are shaping the minds and capabilities of future business leaders and policymakers. This shift has translated to 225 million tons of material flows and $140 billion in total capital mobilized to date (Ellen MacArthur Foundation, 2023).

Despite these successes, Holly noted that the percentage of the total economy that is circular has decreased from 7.2 percent in 2018 to 6.9 percent in 2021 (Circle Economy, 2025). Growth in businesses and economies is persistently linear rather than moving toward circularity.

Turning to the role of plastics in the current and circular economy, Holly explained that 98 percent of plastic production derives from virgin feedstock and only 2 percent is retrieved through recycling. Of the 14 percent of total plastic produced that is collected for recycling, more than the half (8 percent total) undergoes cascaded recycling (also known as downcycling) and almost a third (4 percent total) is lost through processing. Of the total plastic produced annually, 32 percent is leaked (ending up in oceans and ecosystems), 40 percent is landfilled and never used again, and 14 percent is incinerated. Holly noted that by 2040, plastic in the market is expected

to double from 2016 numbers, almost tripling the flow into the ocean and quadrupling the amount of ocean plastic (Ellen MacArthur Foundation, 2022; Pew and Systemiq, 2020).

However, Holly said that EMF believes that solutions exist at the intersection of business and policy. She explained that EMF is calling for business to take bold action on circularizing packaging types that are not recyclable today, problematic plastics, and flexibles; to build up infrastructure; and to set and adhere to ambitious reduction targets. EMF also thinks it is important for governments to establish stable mechanisms for funding through, for example, extended producer responsibility and other policies that enable circular loops and set an international framework for action through the United Nations Environment Programme (UNEP).

Holly offered the EMF Global Commitment as an example of their approach. Launched by EMF and UNEP in 2018, this effort brings together more than 1,000 organizations, including 250 businesses representing the largest packaging creators and users. The primary goal has been to set ambitious targets to reduce virgin plastics, and EMF has been reviewing outcomes to identify what has worked well and what interventions could be employed moving forward. Holly shared that in the first five years, Global Commitment signatories outperformed the market. However, although strong relative to each other and the market, performance is not yet at the scale or level of transition and transformation that would achieve circularity goals. Holly expressed that EMF remains focused on the intersection of business and policy, in order to ensure that the UN Global Plastics Treaty includes mandates, not suggestions, on plastics use. EMF will devote the next five years of its global commitment on addressing key hurdles such as reuse remaining in pilot mode, a lack of infrastructure supporting circularity, and continued use of problematic flexible plastics.

Holly concluded with a quote from Dame Ellen MacArthur, the EMF Founder and Chair of Trustees, “If we get this right, and we innovate, and we are creative, we can build an economy which can thrive and can run forever.”