Andrew – I don’t dispute that high population can have high costs, but I think you know better than I that there are always costs to everything. High population is largely the product of wonderful advances in hygiene and medicine. That’s a good trade-off if you ask me. Similarly, I think people who harp on overpopulation tend to be focusing on the wrong things. High population is a problem when bad polcies are in effect. When good policies are in place, high population isn’t that big a deal. Indeed, in most advanced democratic countries, those good policies yield new problems — like plummeting fertility rates. Again,  there’s a cost-benefit dynamic at work. There are no policy solutions, only policy tradeoffs.