Ashley Nunes’s research while affiliated with Breakthrough and other places

The United States has long pursued regulations that aim to reduce fossil fuel use. However, while potential emission reduction motivates the introduction and enforcement of these regulations, realization of this potential does not obfuscate the need for prudent economic policy. Scrutinizing nearly two decades of climate regulations in the transportation, industrial, and electric power sector, we enumerate their associated cost effectiveness. Our findings are twofold. Firstly, we find that whereas there are instances where climate regulations carry net economic benefits, there are also cases where compliance costs substantially exceed the social cost of carbon (SCC). Aggregated across sectors and subject to the precise SCC leveraged, up to 65 percent of climate regulations have abatement costs that exceed the SCC. This exceedance is particularly profound in the transportation sector where up to 82 percent of regulations reviewed have abatement costs that exceed the SCC. Secondly, we find that whereas the economic benefits of climate regulations generally exceed the economic costs, this exceedance is largely contingent on the presence of non-climate benefits. Aggregated across sectors, climate benefits account for 33 percent of overall benefits associated with a regulation, compared to 18, 46, and 2 percent for public health, private, and other benefits respectively. Furthermore, we document instances where climate benefits account for as little as 1.6 percent of overall regulatory benefits. This finding hints at a regulatory inefficiency and raises the prospect that alternative, non-climate specific regulation may be a more appropriate mechanism for realizing the non-climate benefits associated with these regulations. Collectively, our findings challenge the economic pragmatism of some (but not all) climate regulations adopted by the United States over a period of nearly two decades.

New tailpipe emissions standards aim to increase electric vehicle (EV) sales in the United States. Here, we analyze the associated critical mineral supply chain constraints and enumerate the climate consequences of these constraints. Our work yields five findings. First, the proposed standard necessitates replacing at least 10.21 million new internal combustion engine vehicles with EVs between 2027 and 2032. Second, based on economically viable and geologically available mineral reserves, manufacturing sufficient EVs is plausible and reduces up to 457.3 million tons of CO2e. Third, mineral production capacities in the United States and amongst allies support the deployment of 5.09 million vehicles between 2027 and 2032, well short of compliance target. Fourth, this shortfall produces at least 59.54 million tons of CO2e in lost lifecycle emissions benefits. Fifth, limited production of battery-grade graphite and cobalt may represent particularly profound constraints. Pathways that afford comparable emission reductions are subsequently explored.

Procurement incentives are a widely leveraged policy lever to stimulate electric vehicle (EV) sales. However, their effectiveness in reducing transportation emissions depends on the behavioural characteristics of EV adopters. When an EV is used, under what conditions and by whom dictates whether or not these vehicles can deliver emissions reductions. Here, we document that replacing gasoline powered vehicles with EVs may—depending on behavioural characteristics—increase, not decrease, emissions. We further show that counterfactual vehicle inventory—how many vehicles a household would own absent an EV purchase—is an important influencer of these effects. We conclude that achieving emissions reductions using EVs requires redesigning procurement incentive programmes in a manner that (re)distributes incentives towards the second-hand EV market. Doing so would not only facilitate emissions reductions but also address fiscal prudency and regressivity concerns associated with these programmes.

Government efforts to address child poverty commonly encompass economic assistance programs that bolster household income. The Child Tax Credit (CTC) is the most prominent example of this. Introduced by the United States Congress in 1997, the program endeavors to help working parents via income stabilization. Our work examines the extent to which the CTC has done so. Our study, which documents clear, consistent, and compelling evidence of gender inequity in benefits realization, yields four key findings. First, stringent requisite income thresholds disproportionally disadvantage single mothers, a reflection of the high concentration of this demographic in lower segments of the income distribution. Second, married parents and, to a lesser extent, single fathers, are the primary beneficiaries of the CTC program when benefits are structured as credits rather than refunds. Third, making program benefits more generous disproportionally reduces how many single mothers, relative to married parents and single fathers, can claim this benefit. Fourth and finally, increasing credit refundability can mitigate gender differences in relief eligibility, although doing so imposes externalities of its own. Our findings can inform public policy discourse surrounding the efficacy of programs like the CTC and the effectiveness of programs aimed at alleviating child poverty.

Electric, autonomous vehicles promise to address technical consumption inefficiencies associated with gasoline use and reduce emissions. Potential realization of this prospect has prompted considerable interest and investment in the technology. Using publicly available data from a select market, we examine the magnitude of the envisioned benefits and the determinants of the financial payoff of investing in a tripartite innovation in motor vehicle transportation: vehicle electrification, vehicle automation, and vehicle sharing. In contrast to previous work, we document that (a) the technology’s envisioned cost effectiveness may be impeded by previously unconsidered parameters, (b) the inability to achieve cost parity with the status quo does not necessarily preclude net increases in energy consumption and emissions, (c) these increases are driven primarily by induced demand and mode switches away from pooled personal vehicles, and (d) the aforementioned externalities may be mitigated by leveraging a specific set of technological, behavioral and logistical pathways. We quantify—for the first time—the thresholds required for each of these pathways to be effective and demonstrate that pathway stringency is largely influenced by heterogeneity in trip timing behavior. We conclude that enacting these pathways is crucial to fostering environmental stewardship absent impediments in economic mobility.