The American economist Julian Simon allegedly issued a challenge in 1980 to a group of environmentalists, saying that if scarcity were to be measured in terms of higher prices, they should invest in stocks of any raw metal. The environmentalists put their money on chromium, copper, nickel, tin, and tungsten, and picked a time frame of 10 years.
此外，问题不仅仅是我们还没有耗尽自然资源。据称美国经济学家Julian Simon在1980年向一群环境保护主义者发出挑战，说如果稀缺性是以更高的价格来衡量，那么他们就应该在任何与生金属有关的股票上投资。环境主义者们将资金投入到铬、铜、镍、锡和钨等金属的股票上，投资为期十年。到了1990年，所有这些金属都跌价了：铬跌了5%，锡更是大跌了74%。