Substituting plastics with alternative materials can possibly lead to increased GHG emissions, according to research from the University of Sheffield. The study has revealed the emissions associated with plastic products compared to their alternatives.
- Findings from the study have revealed that in 15 out of the 16 applications examined, plastic products actually result in lower GHG emissions compared to their alternatives. The reduction in emissions spans from 10% to as high as 90% across the product lifecycle.
- The study looked at plastics and their replacements across various applications, including packaging, construction, automotive, textiles and consumer durables. These sectors collectively represent a significant portion of global plastic usage.
THE FINDINGS: The study by Dr Fanran Meng from Sheffield’s Department of Chemical and Biological Engineering, in collaboration with researchers from the University of Cambridge and the KTH Royal Institute of Technology, has revealed the emissions associated with plastic products compared to their alternatives.
- The study, ‘Replacing Plastics with Alternatives Is Worse for Greenhouse Gas Emissions in Most Cases’, is published in the journal Environmental Science & Technology.
THE RESEARCH: The Sheffield academics adopted a lifecycle assessment (LCA) approach to evaluate the GHG emissions associated with plastic products versus alternatives across different sectors.
- Even when focusing solely on direct lifecycle emissions, plastics maintained their advantage in nine out of 14 applications. Factors such as lower energy intensity during production and the weight efficiency of plastics contributed to their reduced environmental footprint compared to alternatives like glass or metal.
- Plastics also demonstrated superiority in upstream processes, including production and transport, in 10 out of 16 applications. This advantage stemmed from their lower energy intensity and lighter weight, highlighting the efficiency of plastic materials in mitigating emissions.
- The study has also revealed the complexity of indirect impacts from background systems surrounding plastics, which play a substantial role in certain applications. For instance, in scenarios like insulation and hybrid vehicle fuel tanks, the indirect impacts overshadow the direct emissions of plastics, presenting a nuanced perspective on their environmental performance.
- The findings suggest that optimising plastic use, extending product lifetimes, boosting recycling rates, and enhancing waste collection systems may offer more effective strategies for reducing emissions associated with plastic products.
- The research team noted that future modelling could be expanded to include reusable bioplastics, compostable and biodegradable alternatives. They were excluded from this study due to small market values and a lack of reliable data about reuse.
WHAT THEY SAID:
Not all alternative or recycled products are better for the environment than the products they replace. Environmental policymaking needs life cycle assessment guided decision-making to make sure that GHG emissions are not unintentionally increased through a shift to more emission-intensive alternative materials. Demand reduction, efficiency optimisation, lifetime extension and reuse/recycling are win–win strategies to reduce emissions effectively. Solely focusing on switching to alternative materials is not.
— Dr Fanran Meng
Assistant Professor in Sustainable Chemical Engineering
University of Sheffield
