Despite the fact that this guy has been unsuccessfully predicting world-wide famine since at least 1970, and virtually all of his ideas have been discredited with the passage of time and reality, he is still the darling of several environmental fund-raising groups.

Has been predicting mass famines world-wide since the 1960s. Notorious for losing a highly publicized bet he made with economist Julian Simon (the bet was that the price of several key commodities would rise/fall over several years). Ehrlich is, I assume, a talented scientist in his field of expertise (the study of insects, particularly butterflies) but his more general theories about the inability of the planet to support a massive increase in human life since the 1960s have proven wrong.