Key Factor in Environmental Impacts
There’s a deeper story behind this work. Initially, it wasn’t intended to be part of our research plan. However, we found ourselves at a crossroads when trying to determine the fate of imported plastic waste. This all started by exploring the environmental impacts of plastic waste trade, a topic that’s particularly intriguing given its controversial nature. On one hand, some advocate for the trade as a component of the circular economy, arguing that plastic waste serves as feedstock for secondary production in Global South countries. On the other hand, critics see it as “waste colonialism,” believing that imported plastic waste exacerbates environmental impacts in these regions, where mismanagement like open dumping and burning is more likely to occur.
After conducting life cycle assessment, we realized that the environmental consequences of plastic waste trade largely depend on the recycling rate of the imported waste. If more of the imported waste is recycled, there are more avoided impacts from reduced virgin plastic production, leading to less share for waste mismanagement and lower overall environmental impacts. Conversely, if less of the waste is recycled, it results in more mismanagement and increased pollution.
Can domestic plastic recycling rates serve as a reliable proxy?
As an alternative, we considered using domestic plastic recycling rates as an alternative. The logic seemed sound—if a country’s domestic recycling rate is as low as 15%, it’s unlikely that the recycling rate for its imported plastic waste would be significantly higher. We encountered this reasoning across various sources. For exmaple, the Guardian article discussed how the UK exported large amounts of plastic waste to Turkey, suggesting that most of this waste was likely mismanaged, given Turkey’s domestic recycling rate of around 15%, with further evidence of mismanagement from Greenpeace. We also came across research published in Nature Communications that used domestic recycling rates to evaluate the environmental impacts of plastic waste trade. However, we had a sense that comparing a country’s general recycling rate with its recycling rate for imported waste is like comparing apples to oranges.
Two reasons against the proxy of domestic plastic recycling rates
We identified two key reasons why using the domestic recycling rate as a proxy wasn’t appropriate (detailed in our paper). First, the domestic recycling rate is usually calculated based on all domestically generated plastic waste, which is often mixed and dirty . In contrast, imported plastic waste is classified as a commodity under the Harmonized System (HS) code, indicating it’s relatively clean and intended for recycling. Second, according to the UN Comtrade database, this “commodity” is purchased by importing countries, incentivizing them to recycle and profit from it, since other waste treatment practices like incineration, landfilling, open dumping, or burning don’t yield any monetary return.
Deducing the Required Recycling Rate (RRR)
A new method focusing on the economic viability of importers came to mind: calculating a required recycling rate (RRR) based on the break-even point between the costs of importing and recycling (including labour, electricity, and real estate rentals) and the value of the recycled plastics.
We assume that the value of recycled plastics is comparable to primary plastics and account for physical losses throughout the recycling process. The import costs and primary plastic values are 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. Data on other costs and physical losses are collected by country and year.
Divergent impacts of recycling rates on environmental assessment
The previously metioned paper in Nature Communications  assessed the environmental impact of China’s plastic import ban using domestic recycling rates for imported plastics. It estimated the net carbon emissions of treating traded plastic waste in 2018 at 0.13 million tonnes CO2-equivalent (CO2-eq). However, in a scenario reflecting a 50% increase in countries’ recycling rates, closely aligning with our calculated RRR for the same period, this figure dropped to -60 kilotonnes CO2-eq. These varying environmental impacts highlight the significant difference between using RRRs and domestic recycling rates to assess the environmental consequences of global plastic waste trade.
Acknowledgments
We extend our gratitude to everyone who contributed to and sponsored this work. Dr. Hauke Ward, who assisted in refining the methodology and in every creative discussion. Prof. Hai Xiang Lin, who suggested that a higher recycling rate might be achieved if the importer covers the cost of plastic waste. Prof. Arnold Tukker, who first questioned the misuse of a country’s general plastic recycling rate and encouraged me to seek better data in July 2023. Special appreciation is extended to Dr. Yanan Liang, whose discussions reminded me of which side actually bears the cost of the waste trade, providing crucial perspective.
We also appreciate the support from the Institute of Environmental Sciences (CML) at Leiden University for sponsoring the publication of this work.Â
In the end
If you’re interested in the full details, feel free to dive into the affiliated paper. For a deeper understanding of the environmental impacts calculated using the RRR method, check out our other paper published in Environmental Science & Technology.
We sincerely hope you find this research insightful and helpful!
All the figures in this post are produced by generative AI to aid understanding.