Economists can and do get it wrong. The lead up to the subprime mortgage crisis being an obvious case in point. While some economists and regulators were convinced all was well, many people were alarmed at a system that enabled people to buy expensive houses with loans that were beyond their means of repaying. It just didn’t pass the common sense test. But have we have learnt our lesson about relying on complex economics that nobody really understands? In the context of climate change legislation, it would appear not.