### Abstract: Analysis Finds Flaw in US Plan to Cut Vehicle Emissions and Suggests Possible Solutions A recent study published in *Nature Communications* by a team of researchers from Harvard and other institutions has identified a significant flaw in the U.S. Environmental Protection Agency's (EPA) plan to reduce vehicle emissions. The analysis, led by Lucas Woodley, Megan Yeo, Ashley Nunes, and others, concludes that the U.S. will fall short of its target to cut vehicle emissions by nearly 15 percent over the next decade due to unrealistic goals for increasing electric vehicle (EV) production. The primary reason for this shortfall is the bottlenecks in the supply chains for crucial minerals such as graphite, cobalt, lithium, and nickel, which are essential for manufacturing EVs and their rechargeable batteries. #### Key Findings and Projections The researchers determined that meeting the new emissions standards would require the replacement of at least 10.21 million internal combustion engine (ICE) vehicles with EVs between 2027 and 2032. However, their estimates suggest that the U.S. and its allies will only be able to support the manufacture of about 5.09 million EVs during this period, falling short by approximately half. This discrepancy would result in nearly 60 million extra tons of carbon dioxide emissions over the next eight years. #### Mineral Supply Constraints The study highlights the critical role of mineral resources in EV production. While the U.S. and its allies have sufficient reserves of raw materials like cobalt, graphite, lithium, and nickel, the production capacity to mine and refine these minerals is severely limited. The challenge is particularly pronounced for graphite, which has not been mined domestically in the U.S. since the mid-20th century. The lack of production capacity for these minerals is a significant barrier to achieving the ambitious EV sales targets set by the EPA. #### Potential Solutions To address the shortfall, the research team suggests exploring hybrid-electric vehicles (HEVs) as an alternative pathway. HEVs require fewer mineral resources compared to fully electric vehicles but still offer a substantial reduction in tailpipe emissions. By incorporating more HEVs into the mix, the U.S. could potentially close the gap on emissions and expand its focus beyond EVs alone. This approach would allow the government to meet its climate goals more realistically and within the constraints of current mineral supply chains. #### Relying on China Another potential solution identified in the study is to increase reliance on China for mineral resources. China is a leading producer of these crucial minerals and has the capacity to meet the U.S.'s growing demand for EV production. However, U.S. lawmakers are hesitant to adopt this approach due to national security concerns. The study poses a critical question: whether Americans value fewer emissions more or prioritize energy security by avoiding dependence on China. #### Research Contributions Megan Yeo, an economics concentrator at Harvard and a co-author of the paper, emphasized the importance of the research in understanding the rigors and constraints of evaluating public policy. Yeo, along with other co-authors, including Peter Cook and Seaver Wang from the Breakthrough Institute, Laurena Huh from MIT, and Daniel Palmer, a high school student from the Groton School, contributed to the comprehensive analysis. Yeo noted that the project provided valuable learning experiences in setting bounds for different scenarios, conducting robustness checks, and making assumptions, skills that are essential for her future career as a public-sector economist. #### Conclusion The study underscores the need for a more pragmatic and flexible approach to reducing vehicle emissions. By considering alternative pathways such as increasing the production of hybrid-electric vehicles and potentially collaborating with China, the U.S. can better align its climate goals with the realities of mineral supply constraints. The research serves as a critical evaluation of the EPA's emissions reduction plan and offers actionable insights for policymakers to consider in their efforts to combat climate change through the transportation sector. This summary is based on a study published in *Nature Communications* and provided by the Harvard Gazette. The full paper, titled "Climate impacts of critical mineral supply chain bottlenecks for electric vehicle deployment," can be accessed via the provided DOI: 10.1038/s41467-024-51152-9.