Cross-scale characteristics and emission reduction pathways of trade-embodied carbon flows in the global supply Chains

In the context of the 1.5 °C warming target, there is a growing awareness of the increasingly frequent carbon flows between subregions. However, understanding the characteristics and pathways of cross-scale carbon flows between subregions and regions remains elusive and impedes achieving emission reduction targets. This study employs a nested multi-regional input–output model and the structural path analysis method, establishing the characteristics of the carbon emission transfer network within global supply chains and discerning the crucial structural pathways and nodes for carbon emissions. The study found that (1) in 36 major countries, the embodied carbon flows are predominantly influenced by the developed countries around China in Asia and the Pacific. (2) In 30 subregions, coastal subregions with large-scale foreign trade and energy-intensive subregions in China's central and western parts contribute significantly to the larger embodied carbon outflow due to exports. (3) “Manufacture of non-metallic mineral products (S09) → construction (S19)” and “manufacture and processing of metals (S10) → construction (S19)” are the two key pathways of paramount significance of embodied carbon emissions. (4) “R25 South Korea” has the highest number of key pathways and the greatest embodied carbon emissions from critical paths, followed by “R27 India” and “R22 United States.” These findings offer valuable insights for the development of regional emission reduction policies.