Publications by Year: 2021

Ramelli, Stefano, Alexander Wagner, Alexandre Ziegler, and Richard Zeckhauser. “Investor Rewards to Climate Responsibility: Stock-Price Responses to the Opposite Shocks of the 2016 and 2020 U.S. Elections.” Harvard Environmental Economics Program, 2021.Abstract
Donald Trump’s 2016 election and his nomination of climate skeptic Scott Pruitt to head the Environmental Protection Agency drastically downshifted expectations on U.S. policy toward climate change. Joseph Biden’s 2020 election shifted them dramatically upward. We study firms’ stock-price movements in reaction. As expected, the 2016 election boosted carbon-intensive firms. Surprisingly, firms with climate-responsible strategies also gained, especially those firms held by long-run investors. Such investors appear to have bet on a ‘‘boomerang’’ in climate policy. Harbingers of a boomerang already appeared during Trump’s term. The 2020 election marked its arrival. (JEL G14, G38, G41)
Aldy, Joseph E., Giles Atkinson, and Matthew Kotchen. “Environmental Benefit-Cost Analysis: A Comparative Analysis Between the United States and the United Kingdom.” Cambridge, Massachusetts, USA: Harvard Environmental Economics Program, 2021.Abstract
The United States and United Kingdom have longstanding traditions in use of environmental benefit-cost analysis (E-BCA). While there are similarities between how E-BCA is utilized, there are significant differences too, many of which mirror ongoing debates and recent developments in the literature on environmental and natural resource economics. We review the use of E-BCA in both countries across three themes: (a) the role of long-term discounting; (b) the estimation and use of carbon valuation; and, (c) the estimation and use of the value of a statistical life. In each case, we discuss how academic developments are (and are not) translated into use and draw comparative lessons. We find that, in some cases, practical differences in E-BCA can be overstated, although in others these seem more substantive. Advances in the academic frontier also raise the question of when and how to update practical E-BCA, with very different answers across our themes.
Aldy, Joseph, Matthew Kotchen, Mary Evans, Meredith Fowlie, Arik Levinson, and Karen Palmer. “Co-Benefits and Regulatory Impact Analysis: Theory and Evidence from Federal Air Quality Regulations.” Discussion Paper (2021): 45.Abstract
This paper considers the treatment of co-benefits in benefit-cost analysis of federal air quality regulations. Using a comprehensive data set on all major Clean Air Act rules issued by the Environmental Protection Agency over the period 1997-2019, we show that (1) co-benefits make up a significant share of the monetized benefits; (2) among the categories of co-benefits, those associated with reductions in fine particulate matter are the most significant; and (3) co-benefits have been pivotal to the quantified net benefit calculation in nearly half of cases. Motivated by these trends, we develop a simple conceptual framework that illustrates a critical point: co-benefits are simply a semantic category of benefits that should be included in benefit-cost analyses. We also address common concerns about whether the inclusion of co-benefits is problematic because of alternative regulatory approaches that may be more cost-effective and the possibility for double counting.
Evans, Mary, Karen Palmer, Joseph Aldy, Meredith Fowlie, Matthew Kotchen, and Arik Levinson. “The Role of Retrospective Analysis in an Era of Deregulation: Lessons from the U.S. Mercury Air Toxic Standards.” Harvard Environmental Economics Program, 2021.Abstract
As of late 2020, the Trump administration had initiated almost one hundred rollbacks of U.S. environmental regulations. A careful assessment of the benefits and costs of rolling back an existing regulation can and should inform such decisions. When assessing the potential rollback of an existing regulation, analysts can often learn from the regulation’s implementation through retrospective analysis as well as from advances in scientific knowledge. We discuss recent actions concerning the Mercury and Air Toxics Standards (MATS) to illustrate the potential lessons from doing so. In the case of MATS, advances in science have shed light on broader exposure pathways and previously unquantified health effects, suggesting that the benefits of reducing mercury emissions may exceed previous estimates. At the same time, changes in the energy sector have altered the mix of fuels used to produce electricity, which impacts both the benefits and costs of the regulation.