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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]

The social cost of carbon is a central metric for optimal carbon prices. Previous literature shows that inequality significantly influences the social cost of carbon, but mostly omits heterogeneity below the national level. We present an optimal taxation model of the social cost of carbon that accounts for inequality between and within countries. We find that climate and distributional policy can generally not be separated. If only one country does not compensate low-income households for disproportionate damages, the social cost of carbon tends to increase globally. Optimal carbon prices remain roughly unchanged if national redistribution leaves inequality between households unaffected by climate change and if the utility of households is approximately logarithmic in consumption. [ABSTRACT FROM AUTHOR]

Most but not all economists view carbon pricing as most effective to combat carbon emissions, whereas other policies are widely applied and highly debated. We quantify the effectiveness of climate policies in the form of pricing carbon and subsidizing renewable energies for Germany's and Britain's power sectors. While Germany relies on heavy subsidies for renewables but on a weak price for carbon certificates (EUA) from the EU Emission Trading System (ETS), its emissions hardly declined. To underpin the low EUA price, Britain introduced a unilateral tax on power sector emissions, the Carbon Price Support (CPS). Within only five years, carbon emissions declined by 55%. Our results demonstrate that in the power sector, even a modest carbon price (∼€30/tCO 2) can induce significant abatement at low costs within a short period as long as "cleaner" gas plants exist to replace "dirty" coal plants. We also find that carbon pricing is superior to subsidizing wind or solar power in these two countries. • We quantify the effectiveness of climate policies in terms of emissions abatement and costs. • While Germany heavily subsidizes wind and solar power, Britain introduced a significant carbon tax on top of the EUA price. • In line with theory, carbon pricing turns out superior to subsidizing wind or solar power. • Even a modest carbon price (∼€30/tCO 2) can induce significant abatement once cleaner gas can replace dirty coal. • In both countries, it costs much less to offset one ton of CO 2 using carbon pricing vis-a-vis subsidized renewables. [ABSTRACT FROM AUTHOR]

We analyze the effectiveness of environmental policy when consumers are subject to social influence. To this end, we build a model of consumption decisions driven by socially-embedded preferences formed under the influence of peers in a social network. This setting gives rise to a social multiplier of environmental policy. In an application to climate change, we derive Pigouvian and target-achieving carbon taxes under socially-embedded preferences. Under realistic assumptions the social multiplier is equal to 1.30, allowing to reduce the effective tax by 38%. We show that the multiplier depends on four factors: strength of social influence, initial taste distribution, network topology and income distribution. The approach provides a basis for rigorously analyzing a transition to low-carbon lifestyles and identifying complementary information and network policies to maximize the effectiveness of carbon taxation. [ABSTRACT FROM AUTHOR]

This paper compares the impact of different climate mitigation policies — mandates, feebates, performance standards, and carbon pricing — in a Ramsey model with clean and polluting capital, irreversible investment, and a climate constraint. These policy instruments imply different transitions to the same balanced growth path. The optimal carbon price minimizes the discounted social cost of the transition to clean capital, but may prompt premature retirement of existing polluting capacities and significant private costs in the form of stranded assets. Second-best mandates and feebates affect new investment decisions without providing incentives to under-use existing polluting equipment. These instruments lead to higher discounted social costs, but smoother abatement costs, and do not result in premature retirement or stranded assets. A phased-in carbon price can avoid premature retirement but still result in stranded assets, that is in a drop of wealth for the owners of polluting capital. We discuss a potential trade-off between the political feasibility and cost-effectiveness of climate mitigation policies. • Carbon prices are efficient but can cause stranded assets. • Feebates and mandates lead to the same long-term outcome as carbon prices. • Feebates and mandates do not create stranded assets. • Phased-in carbon prices avoid premature retirement but not stranded assets. [ABSTRACT FROM AUTHOR]