From The Entropy Law and the Economic Process, first published in 1971: [The fundamental limit of natural resources] also exposes the futility of the human pride that overcame some scholars on learning that by A.D. 2000 we may be able to feed people with proteins derived from crude oil and thus solve the population problem completely and forever. Highly probable though this conversion is, we can rest assured that sometime, perhaps sooner than one may think, man will have to reorient his technology in the opposite direction—to obtain gasoline from corn, if he will still be around and using internal combustion engines. In a different way than in the past, man will have to return to the idea that his existence is a free gift of the sun. (emph. mine) The best part about science? Being far more right than you ever suspected.