Trends in the intensity of copper use in Japan since 1960

For some time, we have known that the intensity of metal use within a country depends on its level of economic development, usually measured by per capita income, as well as on technological change, long-run price trends, and other factors whose influence varies, more or less, with time. This study finds that rising per capita income has increased the intensity of copper use in Japan over the entire period examined. Moreover, this positive effect is expected to continue until per capita income-$44,830 in 2000-reaches $53,000. Thereafter, further advances will tend to reduce the intensity of copper use. Conversely, new copper-saving technologies and other time-related variables have on average reduced the intensity of copper use by 2.9% a year, an amount sufficient not only to offset the positive effects of growing per capita income but also to reduce intensity of use by 38%.