Evaluating the Global Plastic Waste Management System with Markov Chain Material Flow Analysis.

We present a global Markov chain-based material flow analysis of plastic waste of all types to estimate global virgin waste generation and waste mismanagement rates. We model nine alternative scenarios related to the elimination of plastic waste trade and improvements at various stages of the recycling chain, including "limitless" recycling promised by certain new chemical recycling technologies. We found that the elimination of trade increased global mismanagement when displaced waste was disposed but decreased mismanagement when it was instead recycled. Recycling scenarios showed little benefit for limitless recycling without prior increases in collection rates, which are currently the main constraint in the recycling chain. The most ambitious scenario only led to a 34% decrease in virgin waste generation. While significant, this implies that, given our current 40% mismanagement rate and 2050 forecasts of waste generation, landfilling and incineration capacity must increase 2.5-fold in addition to these extreme recycling targets to eliminate waste mismanagement. These results highlight the requirement for waste exporters to increase domestic recycling capacity as trade restrictions become tighter and express the urgent global need for alternative waste reduction interventions in addition to recycling.