世界の非鉄金属消費量の長期見通し

拡張成長曲線で推計したトレンドによる統計的予測

抄録

Consumption of a certain metal in a country increases with time. However, this time-consumption relation is not linear in the long range. Furthermore, population and GDP of a country increases in a non-linear way.
I attempted to estimate the trend of consumption per capita of a metal as a function of GDP per capita. If population and GDP per capita of a country can be estimated as a function of time, then, by using the same formula, consumption of a metal of a certain country can also be estimated as a function of time.
Subsequently, it became necessary to find a suitable formula to describe these non-linear relations; and one which could be used safely in long range extrapolation. I finally found the formula, and named it Extended Logistic Curve. Using this formula, consumption per capita of a metal of a country, or a district, can be estimated as a function of time(t).
The result of this study shows China surpassing America and the whole of Europe in the consumption of Lead and Zinc before 2010, and catching up with America in Cu consumption around 2030, with India 20 years behind China in this respect.
The world demand for refined Copper is estimated to reach 22 million tons by 2020 and 34 million by 2050. For Lead, the figure is 8.5 million tons by 2020 and 10.8 million by 2050. Finally, the estimate for zinc is 11 million tons by 2020, and 14 million by 2050. A supply shortage and raised prices are expected in the future, especially for Copper and Zinc.