In 1980 Ehrlich famously made and lost a bet with Julian Simon based on Ehrlich's predicted scenario of resource scarcity. George Will recalled the bet in a good column on the global warming scare:
Paul Ehrlich, a Stanford scientist and environmental Cassandra who predicted calamitous food shortages by 1990, accepted a bet with economist Julian Simon. When Ehrlich predicted the imminent exhaustion of many nonrenewable natural resources, Simon challenged him: Pick a "basket" of any five such commodities, and I will wager that in a decade the price of the basket will decline, indicating decreased scarcity. Ehrlich picked five metals -- chrome, copper, nickel, tin and tungsten -- that he predicted would become more expensive. Not only did the price of the basket decline, the price of all five declined.
Will added a footnote to this history: "An expert Ehrlich consulted in picking the five was John Holdren, who today is President Obama's science adviser. Credentialed intellectuals, too -- actually, especially -- illustrate Montaigne's axiom: 'Nothing is so firmly believed as what we least know.'" There is much more to the story, making it of current interest, as John Hinderaker noted in "Politicizing science."