Global distribution of material stocks: iron, copper and nickel

Economic growth has caused a rapid rise in the use of metals and minerals. In addition, the world’s population is projected to rapidly increase, with increases concentrated in Asia and Africa. Asia has become the largest global user of natural resources, and established systems of production and consumption are tailored to the current high levels of natural resource use and the associated emissions. Closing the material cycle loop is a principal strategy to reduce natural resource consumption and associated emissions. Material flow analysis (MFA), widely used to assess the flow and stocks of materials within a system defined in time and space, is regarded as a core tool to assess the sustainability of material use. The objective of this study was to estimate material stocks of iron, copper, and nickel, for which the global demand has risen rapidly in recent years. Specifically, the goal was to examine transitions of the material stock of each substance from 1995 to 2010. The worldwide material stocks of iron, copper, and nickel drastically increased during this period, which coincided with an increase in demand for materials in Asia. The material stock of each substance in Asia increased almost threefold from 1995 to 2010. The material stock of iron, copper, and nickel in Asia accounted for 30%, 26%, and 20% of the world total in 1995, respectively, but these percentages increased to 42%, 37%, and 32% in 2010, respectively. There was also a drastic increase in the per-capita material stock of iron, copper, and nickel in Asia during the same period, but the per-capita material stock of each of these substances in Asia was not yet reached that of North America and Western Europe. The material stocks in Africa increased in line with the population growth in Africa from 1995 to 2010, so the per-capita material stock of each substance in Africa stayed about the same. The per-capita material stocks in Africa are also small compared with developed countries and regions. This situation shows the potential for a greatly increased demand as a result of expansions in production through accelerated industrialization as well as the increased demand for resources accompanying population and economic growth in Asia and Africa.