Plastic waste imports & coastal litter: Evidence from citizen science data

Plastic waste is an internationally traded commodity, where importing countries recycle plastic waste into usable materials. However, there are concerns that the importation process creates plastic litter — a negative externality — in importing countries. While this concern has received much media and policy attention, quantifying the magnitude of this externality has been hindered by a lack of data on plastic litter across countries and over time. To this end, we use unconventional citizen science data on litter from Ocean Conservancy’s International Coastal Cleanup, together with the United Nations Comtrade Database, to estimate the correlation between traded plastic waste and coastal litter from 2003 to 2022. We find that a 10% increase in the amount of plastic waste a country imports is associated with a 0.6% increase in the amount of littered plastic collected. Heterogeneity analyses show this correlation is driven by countries with higher rates of waste mismanagement. Our results suggest that the country- and international-level regulatory policies implemented in the waste trade industry since 2018 may have contributed to mitigating plastic pollution.