When circularity conflicts with climate: a circular supply chain analysis of SDG 9, SDG 12, and SDG 13  

Circular Supply Chains (CSCs) are widely touted as the operational nexus for achieving both Respon sible Production (SDG 12) and Climate Action (SDG 13). However, this alignment relies on the often unverified assumption that material recovery is inherently carbon-efficient. This study challenges that axiom by investigating the operational conditions under which circularity strategies inadvertently under mine climate mitigation goals.

Methodology: We develop a closed-loop hybrid-manufacturing–remanufacturing model that integrates reverse logistics topology, carbon intensity, and emissions taxation. Using classical non-linear optimiza tion, we derive closed-form analytical solutions and conduct sensitivity analysis.

Findings: The analysis identifies a structural ”Distance Paradox”: while increasing remanufacturing intensity linearly advances SDG 12, it introduces a convex emission penalty via reverse logistics that can actively negate SDG 13. Our model determines the spatial threshold beyond which the marginal carbon cost of recovery exceeds the emissions avoided from virgin production, creating a ”tipping point” where circularity becomes net-carbon positive.

Originality: This is the first analytical framework to quantify the tripartite trade-offs among SDG 9, 12, and 13. It contributes to the sustainable-operations literature by offering a decision-support tool that decouples resource recovery from carbon generation, ensuring circular strategies are logistically coherent.

Practical implications: The findings provide a corrective to ”blind circularity,” demonstrating that firms must co-optimize logistics infrastructure and recovery rates to avoid environmental trade-offs. We propose that managers prioritize ”spatial clustering” for recovery and that policymakers shift from weight based to carbon-adjusted Extended Producer Responsibility (EPR) frameworks.