Standard environmental economics prescribes policies which are optimal and implemented immediately. The paper argues that, in reality, environmental policy often deviates from the optimum and implementation is not deterministic but subject to major uncertainty and frequent change. We present a...

We derive the optimal contributions to global climate policy when countries differ with respect to income level and pollution intensity. Countries' growth rates are determined endogenously, and abatement efficiency is improved by technical progress. We show that country heterogeneity has a...

Production often causes pollution as a by-product. Once pollution problems become too severe, regulation is introduced by political authorities which forces the economy to make a transition to cleaner production processes. We model this transition as a change in "general purpose technology"...