Major carbon-pricing systems in Europe and North America involve multiple jurisdictions (countries or states). Individual jurisdictions often pursue additional initiatives—such as unilateral carbon price floors, legislation to phase out coal, aviation taxes or support programs for renewable...

"This essay revisits the question of instrument choice for the regulation of externalities in the context of climate change. The central point is that the Pigouvian prescription to equate marginal control costs with the expected marginal benefits of damage reduction should guide the design of...