Most people don’t know what it means, and most of those who know what it means have little or no idea how it’s calculated, but the “social cost of carbon” may be one of the most important concepts—and numbers—in the climate-and-energy-policy debate, and particularly in American regulatory activity. The Obama Administration’s inflated estimate of the

Few people have even the slightest notion how difficult it is to come up with even moderately plausible estimates of global temperature. Every measuring system has its strengths and weaknesses. Those handling them have their abilities and disabilities, their biases and blind spots. And a great deal of what goes on is politically driven to