The global production of plastics has reached alarming levels, with a significant portion ending up in landfills, incinerators, or mismanaged. Since the late 1990s, plastic waste trade flows have increased, with developed countries exporting waste to developing countries. While potentially mitigating resource shortages in developing nations, this practice creates significant environmental impacts from trade and disposal processes. The Basel Convention aimed to address this, but its lack of a clear hazardous waste definition and the reluctance of some major exporters to sign limited its effectiveness. China, the world's largest importer and producer of plastic waste, faced severe environmental issues due to its high import volume and mismanagement rate. To address this, China implemented a ban on most plastic waste imports in 2017. This study addresses the significant gap in research by quantitatively assessing the short- and long-term environmental impacts of this ban on global plastic waste trade flows and treatment systems.

Existing research on the China ban's impact primarily focuses on qualitative discussions, trade effects, or hypothetical estimations of value-added loss and increased waste treatment capacity. However, these studies often neglect the technical differences among countries and fail to provide specific, globally sustainable suggestions for international plastic waste trade. This study builds upon prior work by incorporating technical differences in plastic waste treatment methods and technologies across countries into a global sustainability perspective. It aims to provide specific quantitative assessments of the consequences of the ban and recommend policy improvements.

This study analyzed global plastic waste trade flow patterns before (Baseline Scenario) and after (2018 Scenario) China's ban using data from the UN Commodity Trade Statistics Database (Comtrade). Eighteen countries were included: China, 17 countries accounting for 92% of China's plastic waste imports, and "other countries." The study then evaluated the environmental impacts and eco-costs of these changes using life cycle assessment (LCA). Six types of plastics were considered, and the LCA fully accounted for technological differences among countries, including variations in technological structure and advancement. To predict long-term effects, scenario analysis (SA) was employed. Two scenario types were developed: (1) Export Reduction Scenarios (50% simultaneous or separate export reductions of developed and developing countries) and (2) Recycling Rate Promotion Scenarios (20%, 50%, and 100% increases in recycling rates compared to the 2018 scenario). The environmental impact of five midpoint indicators (global warming, fine particulate matter formation, freshwater ecotoxicity, human carcinogenic toxicity, and water consumption) were assessed using the ReCiPe method. The Eco-cost method was used to aggregate the midpoint indicators into a single monetary value. The formula for calculating the environmental impact of trade flow changes (EIT) considers the environmental impact of domestic management, export, and transportation.

Before the ban, China imported about 55.7% of the world's plastic waste. The ban led to a 45.5% decrease in global plastic waste trade flow in 2018. Hong Kong's role as a transshipment port diminished, and Southeast Asian countries became major alternative destinations, with their imports increasing by 362%. A strong negative correlation was found between a country's reliance on the Chinese market and the change in its export flow after the ban. LCA showed that the trade flow changes resulted in a significant increase in global warming potential, but improvements in other environmental indicators such as fine particulate matter formation, freshwater ecotoxicity, human carcinogenic toxicity, and water consumption. The total annual eco-cost savings were estimated to be €2.35 billion. Scenario analysis predicted further eco-cost savings (1.54–3.20 billion euros) by reducing exports and increasing recycling rates. The 'Half of exports + 20% increase recycling rate' scenario emerged as the most practical and effective option, balancing environmental impact and economic feasibility.

The China ban significantly altered global plastic waste trade flows, shifting the burden of waste management to other countries, particularly in Southeast Asia, and to developed countries' domestic systems. The short-term impact showed a temporary increase in global warming due to increased domestic incineration in developed countries, which have higher incineration rates than China. However, there were positive impacts on other environmental indicators due to the increased domestic management in developed countries. Reducing exports and increasing recycling rates are both effective in mitigating environmental impacts, with scenario analysis suggesting substantial potential for further cost savings. The optimal scenario balances export reduction with a moderate increase in recycling rates to avoid excessive water consumption during the recycling process.

China's plastic import ban had a substantial and multifaceted impact on global plastic waste management. While initially increasing global warming potential, it led to significant improvements in other key environmental indicators and considerable eco-cost savings. For long-term global sustainability, countries need to shift towards more robust domestic waste management systems with increased recycling and reduced reliance on exporting waste. Further research should focus on optimizing recycling technologies and developing sustainable waste management strategies for developing countries.

This study relied on reported trade data, which may contain inaccuracies or inconsistencies. The LCA model made assumptions about waste treatment methods and technological advancements, which may introduce uncertainties. Future research could incorporate more detailed data and refine the LCA model to increase the precision of the results.