Prospective material metabolism and environmental impact of China’s polylactic-acid industry under technology and demand scenarios

Polylactic acid is increasingly used as a renewable alternative to conventional plastics, but industry growth and diversifying production and recycling pathways create uncertainty about its future material flows and environmental impacts. Here we show how material metabolism and environmental impacts of China’s polylactic acid industry from 2018 to 2060 under prospective scenarios of changing demand, feedstock substitution and emerging recycling technologies. Consumption is projected to reach 3.88 × 10⁵ tonnes by 2060, shifting toward tubes and coating applications as drinkware demand grows. Feedstock substitution shows overall potential to reduce the industry’s environmental impacts, although polylactic acid consistently has higher marine eutrophication and human toxicity impacts than conventional plastics. Polylactic acid produced from bamboo residue achieves the largest reduction in environmental impacts, reducing human health impacts by 58.7%. Under integrated scenarios combining feedstock substitution and recycling, environmental impacts peak around 2050 and decline by 2060, with human health impacts decreasing by 39.2%, highlighting the environmental benefits of integrating these strategies. Polylactic acid use in China is projected to reach 388,000 tonnes by 2060; bamboo residue feedstocks reduce human health impacts by 58.7%, and combined feedstock substitution and recycling cut impacts by 39.2%, according to material flow and life cycle assessment scenarios