David Henderson, John Cochrane, Wall Street Journal: Climate change is often misunderstood as a package deal: If global warming is “real,” both sides of the debate seem to assume, the climate lobby’s policy agenda follows inexorably. It does not. Climate policy advocates need to do a much better job of quantitatively analyzing economic costs and the actual, rather than symbolic, benefits of their policies. Skeptics would also do well to focus more attention on economic and policy analysis. To arrive at a wise policy response, we first need to consider how much economic damage climate change will do. Current models struggle to come up with economic costs consummate with apocalyptic political rhetoric. Typical costs are well below 10% of gross domestic product in the year 2100 and beyond.