Deniz Koca

Global production rates of metals vary from iron at 1.4 billion ton per year to platinum with 200 ton per year. Resource scarcity starts to manifest itself in rising prices and supply limitations, and metal substitution has been a major argument among economists when putting considerations of resource scarcity aside. Here we investigate the potential limits to metal substitution. Present consumption, recycling and irreversible loss rates, as well as the metal balances and properties are examined. Our findings suggest that the major limitations and issues to substitution are: (1) Physical limitations in terms of metal available; it can only take place by a more abundant metal taking partly the place of a metal produced in smaller amounts; (2) Functional limitations based of differences in physical and chemical properties; and (3) By considering substitution options often more energy is needded and larger CO2 emissions occur. Substitution of metals is therefore not going to take the threat of scarcity away; it can only delay us in adapting to the level of sustainable use. The longer we wait, the more we risk squandering resources before we properly conserve our resources from becoming scarce