Estimated material metabolism and life cycle greenhouse gas emission of major plastics in China: A commercial sector-scale perspective

Plastics are one of the most greenhouse gas (GHG) intensive and the fastest growing industries in the manufacturing sector. Environmental tradeoffs of plastics occur through all stages of their life cycles, accelerating climate breakdown and threatening our ability to maintain a sustainable climate. Herein, material flow analysis (MFA) of three major synthetic resins (PVC, PP, PE) in China was first conducted from production to end-of-life. Meanwhile, life cycle assessment (LCA) was applied to investigate "cradle-to-gate " environmental impacts of these synthetic resins, and then GHG emissions during each plastic life stage were quantified by the integrated LCA-MFA framework. Results suggested that GHG emissions during resin production were 5.42, 4.72 and 3.43 kg CO(2)eq for 1 kg PVC, PP and PE, respectively. Taken together, China generated 304 million metric tons (Mt) CO(2)eq in 2020 by synthetic resin production, and additional 44 and 55 Mt CO(2)eq were emitted due to further plastic product manufacturing and end-of-life management, respectively. Packaging was identified as the major GHG contributor during the use phase, which should be critically monitored for GHG management. The study provides a new perspective to reveal environmental hotspots that drive GHG emissions among plastic life cycles and guides policy-makers towards effective carbon control and sustainable plastic management.