Metacoupling flow of embodied carbon in resource-based cities: A case study of Hohhot-Baotou-Ordos-Yulin urban agglomeration in China

Quantifying embodied carbon flow is essential for resource-based cities (RBCs) to achieve carbon neutrality and sustainable development goals. However, previous studies have limited understanding of the differences in embodied carbon flows over varying distances, impeding a systematic understanding of these flows in RBCs. Based on the metacoupling theory and the environmentally extended multi-regional input-output (MRIO) model, this study proposed a novel framework that comprehensively depicts local, adjacent, and distant flows of regional embodied carbon. Taking the Hohhot-Baotou-Ordos-Yulin (HBOY) urban agglomeration as an example, we first defined adjacent and distant systems, then quantified the three flow processes of embodied carbon in HBOY using a city-province nested MRIO model. The findings indicated significant differences among the three flow processes. In local flows, Ordos was the only net exporter of embodied carbon, with over half flowing to Hohhot. In adjacent flows, HBOY net imported 7.23 Mt of embodied carbon from nearby regions, while in distant flows, it net exported 165.26 Mt to distant regions. Notably, the embodied carbon imported from the adjacent and distant systems was similar, at 58.17 Mt and 55.06 Mt, respectively, yet the export to the distant system was 4.7 times higher than that to the adjacent system. Nearly four-fifths of HBOY's local carbon emissions are used to satisfy consumption in other regions, which is prevalent in RBCs. Therefore, we recommend that RBCs and their trading partners establish an emission reduction responsibility sharing mechanism aligning duties with benefits, and devise practical carbon compensation schemes and tailored cooperation plans.