The three Kyoto flexible mechanisms emissions trading, the clean development mechanism (CDM), and Joint Implementation (JI) have always been controversial. Proponents saw the mechanisms as clever tools to ensure environmental outcomes were achieved at least cost. Reducing the costs of...

Research into the social cost of carbon emissions - the marginal social damage from a tonne of emitted carbon - has tended to focus on "best guess" scenarios. Such scenarios generally ignore the potential for low-probability, high-damage events, which are critically important to determining...