How do your friends explain the fact that the Ehrlichs made their prediction for the 1970's, which are already in the past? I can see that interpretation of Nordhaus by someone who looks at his numbers instead of his rhetoric. It's occurred to me that perhaps Nordhaus is a skeptic who uses the alarmist rhetoric to get people to believe his numbers, but I don't think it likely. I have a low opinion of Noah Smith because he wrote a piece on Adam Smith that was wildly wrong, trying to represent Smith as a modern progressive. I put an explanation of the errors on his comment thread, he responded to other things in the comment thread but not mine, so I concluded that he did not care whether what he wrote was true. For some details see:http://www.daviddfriedman.com/Ideas%20I/Economics/Adam%20Smith.pdf