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Economists tend to view a uniform emissions price as the most cost-effective approach to reducing greenhouse gas emissions. This paper scrutinizes the assumptions in general equilibrium which underlie the established view that uniform emissions pricing is optimal, focusing on economies where society values the well-being of future generations more than private actors. When social and private discount rates differ, we show that a uniform carbon price is optimal only under restrictive assumptions about technology homogeneity and intertemporal decision-making. Non-uniform pricing spurs capital accumulation and benefits future generations. Depending on sectoral heterogeneity in the substitutability between capital and energy inputs, we find that optimal carbon prices differ widely across sectors and yield substantial welfare gains relative to uniform pricing. Realizing these welfare gains, however, requires that the regulator has information on the technology heterogeneity across sectors. Differentiated carbon pricing based on imperfect estimates of technology heterogeneity can yield significant welfare losses. [ABSTRACT FROM AUTHOR]

Climate policy needs to set incentives for investors who face imperfect, distorted markets and large uncertainties about the costs and benefits of abatement. These investors decide on uncertain investments according to their expected return and risk (carbon beta). We study carbon pricing and financial incentives in a consumption-based asset pricing model distorted by technology spillovers and time-inconsistency. We find that both distortions reduce the equilibrium asset return and delay investment in abatement. However, their effect on the carbon beta and the risk premium for abatement can be decreasing (when innovation spillovers are not anticipated) or increasing (when climate policy is not credible). We show that the distortions can be overcome by modified carbon pricing by a regulator, or by financial incentives, implemented in our model by a long-term investment fund. The fund pays a subsidy to reduce technology costs or offers financial contracts to boost investment returns to complement the carbon price. The investment fund can thus pave the way for carbon pricing in later periods by preventing a capital misallocation that would be too expensive to correct, thus improving the feasibility of ambitious carbon pricing. [ABSTRACT FROM AUTHOR]

Carbon dioxide removal (CDR) moves atmospheric carbon to geological or land-based sinks. In a first-best setting, the optimal use of CDR is achieved by a removal subsidy that equals the optimal carbon tax and marginal damages. We derive second-best policy rules for CDR subsidies and carbon taxes when no global carbon price exists but a national government implements a unilateral climate policy. We find that the optimal carbon tax differs from an optimal CDR subsidy because of carbon leakage and a balance of resource trade effect. First, the optimal removal subsidy tends to be larger than the carbon tax because of lower supply-side leakage on fossil resource markets. Second, net carbon exporters exacerbate this wedge to increase producer surplus of their carbon resource producers, implying even larger removal subsidies. Third, net carbon importers may set their removal subsidy even below their carbon tax when marginal environmental damages are small, to appropriate producer surplus from carbon exporters. [ABSTRACT FROM AUTHOR]