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Working Paper -“Not So Clear: Revisiting the Impacts of Cap-and-Trade on Environmental Justice”

Political Economy Research Institute, UMass Amherst – Working Paper Series Number 579
ByDr. Michael Ash and Dr. Manuel Pastor

Political Economy Research Institute

Updated July 25, 2023


A recent article by Danae Hernandez-Cortes and Kyle Meng (HCM) suggests that the cap-and-trade program in California was accompanied by improvements in the degree of environmental inequity in the state. We note that that the model used to estimate this improvement is not well-designed to capture the variation in facility adjustment to the cap-and-trade program that is at the heart of the environmental justice debate about potential shifts in co-pollutant exposure. We also show that even if that were a proper approach, the estimates offered by HCM may be problematic due to data issues, including proper identification of facilities subject to the cap, shifting results when we require that facilities have observations both before and after the cap, and robustness when we apply their method estimates beyond their selected subsample to the broader range of facilities. As such, the environmental justice implications of California’s carbon market remain an unsettled empirical question.