This study applies a comprehensive framework—the Net-Zero, Nature-Positive, and People-Positive (NZCMI) Framework—using the Chemicals and Materials Industry (CMI) model to analyze the polyester fiber industry [9]. Polyester is a widely used material with significant environmental and social footprints, making it an ideal case study to evaluate system-wide transitions. We first validate the results of the CMI model by comparing them with data reported in existing literature, confirming that the model accurately reflects known trends in polyester production. Following this, a sensitivity analysis reveals that circularity—the reuse and recycling of materials—is a key factor for reducing both greenhouse gas emissions and production costs.
Our findings show important trade-offs between different sustainability goals. When we analyze net-zero, nature-positive, and people-positive outcomes separately, it becomes clear that improvements in one area can sometimes create challenges in another. For example, switching to biobased materials and renewable energy helps reduce carbon emissions, but can also lead to increased resource extraction, land use change, and risks to biodiversity. We observe that circularity has the potential to reduce emissions by nearly 40% when shifting from a no-recycling to a full-recycling scenario. However, the current model includes only a single recycling cycle, and future work should account for material quality degradation and multiple cycles for a more realistic outlook. Although the global outlook may appear positive for nature- and people-centered strategies, a closer look at individual countries tells a different story. Most countries have already exceeded their safe and fair environmental and social limits. Circular economy solutions—such as increased recycling and material reuse—can help reduce these pressures, but they require major investments in infrastructure. In some regions, these investments could increase social and economic inequality if the benefits are not shared fairly. Our regional analysis shows that while some countries appear within social thresholds, they often exceed environmental limits—highlighting the need for local assessments, not just global averages. Improving labor conditions and making sustainable materials more accessible to all are also important steps toward people-positive outcomes. However, these changes may lead to higher short-term production costs, especially in regions with limited resources. Even so, our analysis identifies several opportunities for “win-win-win” outcomes. When circular economy practices, biobased materials, and clean energy are applied in ways that are both sustainable and fair, they can reduce emissions, support ecosystem health, and deliver social and economic benefits—such as creating jobs in rural areas and improving long-term resource security. For example, biobased feedstocks, when sourced responsibly and integrated into local supply chains, can help drive rural employment and reduce supply risks. Similarly, the rollout of renewable energy—if done with community engagement and benefit-sharing—can reduce energy costs and increase access to reliable electricity in underserved areas. These findings highlight the complex task of balancing environmental, ecological, and social goals. They show the need for integrated strategies that combine technology, policy, and circular practices. To make progress on all fronts, technological innovations such as carbon capture and electrified processes must be supported by ecosystem restoration and social safeguards. While carbon capture can reduce emissions, it cannot replace the need for natural solutions or social equity measures. Achieving sustainability in polyester production—and more broadly across the chemicals and materials industry—requires a shift in thinking. A system-wide, collaborative approach is essential to ensure that efforts to reduce emissions and restore ecosystems also support social well-being.
Going forward, decision-makers will require robust and transparent tools that can assess trade-offs and synergies across net-zero, nature-positive, and people-positive outcomes. In this work, we also aim to develop reliable and quantitative metrics that can guide such evaluations and support more informed, balanced decision-making. Building such frameworks will be key to designing sustainable pathways that reflect real-world constraints and local priorities. Addressing these challenges now is critical for building a future where industries and societies can grow in ways that are both sustainable and fair.
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