Decarbonizing Composites: Policy‐Oriented Review of Carbon Footprint, Circularity, and Carbon Trading

Composite materials have been used since ancient times, notably in the form of “Cob,” where clay, earth, straw, and organic matter were combined to improve building performance. Many composite materials rely on carbon‐intensive binders, fibers, fillers, or petroleum‐derived polymer matrices, raising concerns about life cycle emissions, recyclability, and end‐of‐life management. Global climate commitments have triggered a shift toward carbon neutrality. The industry is transitioning from trend‐driven “green” claims to measurable environmental compliance. Hence, this review examines how sustainable composite materials intersect with carbon governance mechanisms, including carbon taxes, emissions trading systems, and voluntary carbon markets, as well as the differentiation of carbon‐accounting categories. The review also evaluates how life cycle assessment, circularity, and end‐of‐life pathways influence the credibility of sustainability claims. In summary, sustainable composites can support decarburization, but their eligibility for tradable carbon credit remains limited and depends on recognized methodologies, additionality, permanence, monitoring, reporting, and verification. From ancient Cob to modern concrete, composites have shaped construction. Now, the focus shifts to sustainability—where bio‐based, circular, and carbon‐neutral materials are redefining the future of building.