Energy-induced mercury emissions in global supply chain networks: Structural characteristics and policy implications

Mercury emission flows in the global supply chains have evolved into an ever-increasing complex network. However, the underlying structural features remain unknown. Therefore, the global embodied mercury flow network was constructed to reveal the characteristics of energy-induced mercury emissions embodied in international trade at both national and sectoral scales. The small-world nature of the global mercury flows network was identified at both scales. Results showed that the global mercury flow network can be divided into 4 national communities, within which the spillover effects of the interventions in one region spread more easily. Detecting the mercury-intensive supply-chain clusters highlights the importance of monitoring these clusters that dominate mercury emissions in global supply chains, which could offer insights on where policy can be implemented effectively. Moreover, vital regions (e.g., mainland China, the USA, and Germany) and sectors (e.g., Petroleum, Chemical and Non-Metallic Mineral Products, Metal Products and Electrical and Machinery in mainland China) for global mercury control have been unveiled by using an integrated centrality measurement system. Our results highlight that, for the overall mercury reduction, regional and even global collaboration should be enhanced along with efforts in individual regions, and enterprises in these important sectors should invest more to green their cluster-wise supply chains.