Optimal Carbon Taxes with Non-Constant Time Preference

The paper derives an explicit formula for the near-term carbon price in a dynamic stochastic general equilibrium climate model in which agents employ arbitrary non-constant time preference rates. The paper uses a simplified version of the model in Golosov et al. (2011), though we argue that the added assumptions are unlikely to matter for our conclusions. The formula is derived first under the assumption that the initial decision-maker has a commitment device, then solving for the unique subgame perfect equilibrium. Somewhat remarkably, the near-term carbon price is the same in both cases. We further show that the near-term carbon price remains unchanged for all potential beliefs about the time preference structure of future generations. It follows that concerns about time inconsistency can be safely ignored when applying the derived formula. The carbon price is the same as the Pigouvian tax in the equilibrium with commitment, and it is bigger than the Pigouvian tax in the equilibrium without commitment provided damages are sufficiently persistent. The formula reduces to the carbon price formula in Golosov et al. (2011) when discounting is constant, and it reduces to the carbon price formula in Gerlagh and Liski (2012) when discounting is quasi-hyperbolic

The Effect of Leaded Aviation Gasonline on Blood Lead in Children

Lead is a neurotoxin with developmentally harmful effects in children. In the United States, over half of the current flow of lead into the atmosphere is attributable to lead-formulated aviation gasoline (avgas), used in a large fraction of piston-engine aircraft. Deposition of lead from avgas may pose a health risk to children proximate to airport facilities that service lead-emitting aircraft. Extrapolating from epidemiological evidence on the health and human capital costs of lead poisoning, various public interest firms have petitioned the EPA to find endangerment from and regulate lead emitted by piston-engine aircraft. In the absence of sufficient empirical evidence linking avgas to blood lead levels (BLLs) in children, the EPA has ruled against petitions to find endangerment. To address an EPA request for more evidence, we constructed a novel dataset that links time and spatially referenced blood lead data from 1,043,391 children to 448 nearby airports in Michigan, as well as a subset of airports with detailed data on the volume of piston-engine aircraft traffic. Across a series of tests, and adjusting for other known sources of lead exposure, we find that child BLLs: 1) increase dose-responsively in proximity to airports, 2) decline measurably in children residing in neighborhoods proximate to airports in the months after 9-11, and 3) increase dose-responsively in the flow of piston-engine aircraft traffic. To quantify the policy relevance of our results, we provide a conservative estimate of the social damages attributable to avgas consumption

The Effect of Leaded Aviation Gasonline on Blood Lead in Children

Lead is a neurotoxin with developmentally harmful effects in children. In the United States, over half of the current flow of lead into the atmosphere is attributable to lead-formulated aviation gasoline (avgas), used in a large fraction of piston-engine aircraft. Deposition of lead from avgas may pose a health risk to children proximate to airport facilities that service lead-emitting aircraft. Extrapolating from epidemiological evidence on the health and human capital costs of lead poisoning, various public interest firms have petitioned the EPA to find endangerment from and regulate lead emitted by piston-engine aircraft. In the absence of sufficient empirical evidence linking avgas to blood lead levels (BLLs) in children, the EPA has ruled against petitions to find endangerment. To address an EPA request for more evidence, we constructed a novel dataset that links time and spatially referenced blood lead data from 1,043,391 children to 448 nearby airports in Michigan, as well as a subset of airports with detailed data on the volume of piston-engine aircraft traffic. Across a series of tests, and adjusting for other known sources of lead exposure, we find that child BLLs: 1) increase dose-responsively in proximity to airports, 2) decline measurably in children residing in neighborhoods proximate to airports in the months after 9-11, and 3) increase dose-responsively in the flow of piston-engine aircraft traffic. To quantify the policy relevance of our results, we provide a conservative estimate of the social damages attributable to avgas consumption

Are Sub-National Agreements for Carbon Abatement Effective?

Although national commitments to the Paris Climate Accord have waned, carbon mitigation by sub-national entities is on the rise globally. We examine the effectiveness of sub-national jurisdictions (e.g., states, provinces, cities) in collectively enacting greenhouse gas abatement strategies. We develop a simple model to explore the conditions under which an agreement among sub-national jurisdictions within a country may lead to substantial carbon abatement relative to a national policy determined through majority rule. We find that, in the absence of a functional national policy response, a coordinated sub-national agreement can generate meaningful abatement. This could form an important stopgap measure in the absence of better alternatives