@EnergyNumbers Somehow I suspect you already know the answer to your IPAT question, but are waiting for other people to provide a good answer. Am I correct?

@THelper I just wanted to contribute something to theme of the week. Population is a problematic subject, with little light and much heat. I thought that IPAT might be a relatively benign way to come at the problem, and hope to draw out some contributors into answering it. I don't intend to post an answer myself, but I'm not going to rule it out forever.