Decoupling Status of Metal Consumption from Economic Growth

Abstract

The decoupling statuses of the consumption of 22 kinds of metals from economic growth were analyzed. Metals were Fe, Al, Cu, Cr, Zn, Mn, Pb, Ni, Co, Sn, Sb, Si, Mo, W, Li, In, Ga, Ag, Au, Pt, Pd and rare earths. The relations between the per capita annual consumption of each metal and per capita GDP were approximated by a two-steps linear formula of yM=aM,1 X (X cM), where yM is the annual consumption of a metal M, and X is GDP per capita. Metals which had only a single relation of yM=aM,1 X were judged to be in a state of coupling. When aM,1>aM,2, the state was judged to be decoupling. Furthermore, a metal was judged to be in a state of absolute decoupling when aM,2<0. The metals which tended to exhibit characteristics of absolute decoupling were Au, Sn, Zn and W, while Cu and Pb were borderline. While Fe, Al, Ni, Mo, Sb, Ag, Pd are decoupling from per capita GDP, Si and Pt are still coupled with economic growth. In the cases of Co, Li, In, Ga and rare earths, a new coupling relation with economic growth has developed over the past several years.