Huffington Post: To tackle climate change without the help of Congress, the Obama Administration will have to estimate how much it costs society -- in damaged crops, wildfires, floods, and a cascading list of other harms -- when a ton of carbon dioxide is released into the atmosphere Obama's administrators estimate the cost to be $38 per ton. In a recent post on Slate, Professor Eric Posner argues that this number is based on a "dubious set of calculations." He worries $38 is so far-fetched that any rule that relies...