We show that, in a model without commitment to future policies, geoengineering breakthroughs can have adverse environmental and welfare effects because they change the (equilibrium) carbon taxes. In our model, energy producers emit carbon, which creates a negative environmental externality, and...

We introduce the possibility of direct punishment by specialized enforcers into a model of community enforcement. Specialized enforcers need to be given incentives to carry out costly punishments. Our main result shows that, when the specialized enforcement technology is sufficiently effective,...