Multinational dynamic steel cycle analysis reveals sequential decoupling between material use and economic growth

Decoupling material use from economic growth is a prerequisite for alleviating the adverse effects of anthropogenic material use and achieving the Sustainable Development Goals. In this study, we combine dynamic material flow analysis with decoupling analysis to examine the relationship between the iron and steel cycle and economic growth in 23 industrialized countries from 1860 to 2018. Specifically, we employ both the quadratic and asymptotic functions to fit the relationship of per capita steel flow/stock indicators at six life cycle stages, including domestic production and apparent consumption of iron ore, pig iron, crude steel, finished steel, and fabricated steel, as well as in-use stock, against per capita GDP. A sequential decoupling between steel flow/stock indicators and GDP growth along the iron and steel cycle is evident. The historical dynamics of the comparative advantage of material flow indicators depict the wave-like geographic diffusion of industrialization. The mechanisms underlying the evolution of material-economy relationship can be attributed to resource endowments, industry policies, trade effects, and lock-in effect of in-use stock. Understanding this phenomenon can facilitate policy-making to promote dematerialization and improve material efficiency in developing countries.