Scientists at Leiden University in the Netherlands have argued that the recycling rate of plastic waste imported from the Global North to the Global South may be underestimated. If true, the environmental impact of traded plastic waste may have been overestimated in the past decade.
In a study published in nature communications, the academics note that existing studies often assume that the recycling rate for imported plastic waste is equal to the domestic recycling rate of the country where the waste is imported to. The team challenges that assumption, arguing that plastic waste importers have a significant economic incentive to recycle the waste into valuable materials since they paid for it.
Assuming instead that at least part of the imported plastic is converted into economically valuable outputs through recycling to offset initial costs, the researchers introduced the Required Recycling Rate (RRR) for importers to break even. The RRR is defined as the breaking point where the revenue from mechanical recycling matches the costs of imports and the recycling process (labour, electricity, and real estate rentals).
The team estimated the RRR for the 22 largest plastic waste-importing countries from 2013 to 2022. They assumed that recyclates can be sold at prices comparable to primary plastics and also accounted for losses throughout the recycling process. Import costs and primary plastic values were derived from 186,861 bilateral trade records for four plastic wastes (PE, PS, PVC and others) and six primary plastics (HDPE, LDPE, PS, PVC, PET and PP) from the UN Comtrade database.
Results show that on average 63% of the imported plastic waste must be recycled to offset the costs. That compares to an average domestic recycling rate of 23%, a difference of 40 percentage points.
“This discrepancy subsequently affects the estimation of the amount of plastics recycled from the waste traded from the Global North to the Global South,” the study’s authors said. “Using the national plastic recycling rate, the annual amount of recycled plastics from the plastic waste trade from the Global North to the Global South averaged 0.37 million tonnes per year over the past five years (2018–2022). In contrast, the annual recycling volume surges to 1.04 million tonnes per year if the RRR is used, an increase of 0.67 million tonnes per year, roughly equivalent to France’s recycled plastics output in 2022.”
The scientists added that such variations in recycling rates can lead to differing estimates of the environmental impacts of the plastic waste trade, given that higher recycling rates suggest reduced emissions from the avoided virgin plastic production. For example, they noted that using the RRR of a country’s domestic recycling rate to assess the impact of China’s plastic import ban in 2018 leads to very different results. Using the domestic rate, the estimated net carbon emissions of treating traded plastic waste in 2018 was 0.13 Mt CO2 equivalent. Using the RRR for the same period, the figure drops to -60 Kt CO2 equivalent.
“RRR enhances the accuracy of modelling the fate and impacts of traded plastic waste, which is crucial for scientific research and policy implementation. By indicating the proportion of recycling versus non-recycling, RRR provides valuable data for assessing the environmental impacts of the global plastic waste trade, particularly in waste-importing countries,” the academics concluded.