(390y) A Product-Level Framework for Designing Net-Zero Emissions Pathways and Processes Using the CMI Model

Meeting the goals of the Paris Agreement requires limiting the global average temperature increase to 1.5°C above pre-industrial levels. Products from the chemicals and materials industry (CMI) contribute to nearly three-quarters of global embedded greenhouse gas (GHG) emissions [1], highlighting the urgent need to transition toward net-zero—or even net-negative—emissions. In response, industries and organizations across sectors are actively developing and publishing roadmaps to guide their progress toward these climate targets [2, 3]. However, these roadmaps often fall short when it comes to providing detailed, product-level insights—particularly for individual materials and chemicals that are deeply embedded in complex global value chains. While they typically outline high-level sectoral targets and broad technological shifts, they rarely account for the specific trade-offs, interdependencies, and regional variations that influence material-specific transitions. Many of these roadmaps treat technologies and sectors as separate and independent, assuming that resources like renewable energy or bio-based materials will be easily available everywhere. They often miss how different materials rely on the same infrastructure or production systems. They also tend to overlook how reducing emissions from one material may affect the ability to reduce emissions from others—especially in industries where multiple products are made together, such as in the chemicals and materials sector. Compounding this issue is a lack of data transparency, as many roadmaps rely on proprietary datasets that cannot be easily accessed or applied for open, product-level analysis [4, 5]. This limits the ability of researchers and stakeholders to check assumptions, compare results across materials, or apply the same data to different regions. Without open and consistent data, it becomes harder to connect global goals with practical decisions, especially for materials with different supply chains and waste management systems in different parts of the world. On the other end of the spectrum, product-specific net-zero roadmaps do exist for certain materials, but these often strip away broader system context [6, 7]. They tend to overlook shared infrastructure, how products are made together, and how changes in one product affect others. This can lead to mistakes in how emissions and costs are assigned and can miss important trade-offs or opportunities to improve more than one product at once. Focusing on a single product can also lead to unexpected problems, such as overuse of resources, material shortages, or delays in other parts of the system. For example, a roadmap that promotes more bio-based materials might ignore competition for land, threats to biodiversity, or effects on other industries that depend on the same raw materials. These roadmaps also often use different starting points, boundaries, or assumptions, which makes it hard to connect them to broader national or industry-level plans. As a result, both general and product-focused roadmaps risk promoting strategies that appear sound in isolation but fall short in practice. There is a clear need to develop integrated approaches that address these limitations—combining open, transparent data with system-level modeling and product-level detail to support credible, actionable pathways to sustainability.

We address the gap in product-level interpretability within global models by introducing a framework that extracts product-specific process chains from the Chemicals and Materials Industry (CMI) model. Among the available tools, the CMI model offers a unique advantage—being openly accessible and freely available—while capturing a comprehensive superstructure of both current and emerging technologies relevant to the sector [8, 9]. Its matrix-based structure enables seamless integration with life cycle inventory datasets, allowing for the evaluation of trade-offs across economic, environmental, social, and circularity objectives for a wide range of production pathways. However, when operating at a global scale across many products, models like CMI often generate results that are difficult to interpret at the level of a single product or stakeholder. Our framework addresses this limitation by tracing the environmental and economic implications for individual products under various system-wide objectives such as emissions or cost minimization. This framework helps illustrate how supply chains shift when priorities change—for example, how a product’s upstream processes are affected when the system moves from cost to emissions reduction. It also makes it possible to separate emissions that occur within a producer’s operations from those that occur upstream or downstream, supporting analysis of responsibility and action. Stakeholders can see what part of a product’s chain they influence, where most of the impact comes from, and how trade-offs between cost and emissions play out under different strategies.

We apply this approach to a case study of polyester fiber, a widely used synthetic material with a complex and emissions-intensive production route. Using the global CMI model, we extract the optimized process chains for polyester under both emissions and cost objectives and discuss various scenarios that support progress toward net-zero emissions in a sustainable way. This method provides practical insight for producers, regulators, and other actors interested in reducing emissions or planning for low-carbon materials. While our case study focuses on polyester, the same method can be applied to any product in a global CMI model. This work offers a way to connect high-level system modeling with practical, product-level insight—supporting better decisions in sustainability transitions across industry.

References
[1] Circularity Gap Report 2020 - Insights - Circle Economy.

[2] IATA. Net Zero Roadmaps.

[3] IEA. Net Zero by 2050 – Analysis, May 2021.

[4] The path to net zero: A guide to getting it right | McKinsey.

[5] Carbon Minds. Pathways for the global chemical industry to climate neutrality.

[6] Iron and Steel Technology Roadmap – Analysis, October 2020.

[7] Zhitong Zhao, Katie Chong, Jingyang Jiang, Karen Wilson, Xiaochen Zhang, and Feng Wang. Low-carbon roadmap of chemical production: A case study of ethylene in China. Renewable and Sustainable Energy Reviews, 97:580–591, December 2018.

[8] Amrita Sen, George Stephanopoulos, and Bhavik R. Bakshi. Mapping anthropogenic carbon mobilization through chemical process and manufacturing industries. In Computer Aided Chemical Engineering, volume 49, pages 553–558. Elsevier.

[9] Amrita Sen, Vyom Thakker, George Stephanopoulos, and Bhavik Bakshi. A novel framework for design of net-zero chemical systems: Analysis and results. In 2023 AIChE Annual Meeting. AIChE.