The Two Numbers Climate Economists Can’t Stand to See Together

Okay, fine. You're persuaded that climate change is a problem. So if we can work out the costs and benefits of reducing carbon emissions, we'll be able to decide on the cheapest course of action, right?

Not so fast. The two numbers that you'd need to do that apparently shouldn't be compared, under penalty of lectures from either climate scientists or economists. Both numbers come from separate draft reports that are still being finalized by the Intergovernmental Panel on Climate Change.