单边废物贸易规制的全球影响

China banned imports of several waste categories beginning in 2017. Exploiting variation between banned waste materials and exempt regular materials, I combine a difference-in-differences approach with the gravity model of trade to estimate its impact on global waste flows. My results show that the ban led to an overall decline in international waste flows, primarily through the reduction in imports by China. While some of the low-value waste materials like plastics were diverted to other lower-income countries, overall trade in high-value waste like metals declined. Back-of-the-envelope calculations suggest that low-income countries saved 1.3–3.8 billion USD in external costs by 2020, roughly 14%–32% of the savings by China. My results indicate that a unilateral regulation can meaningfully lower environmental costs beyond the regulation-imposing country.