Climate Impact of Primary Plastic Production

Plastics show the strongest production growth of all bulk materials over the last decade. The industry’s current growth trajectory is exponential and plastic production is expected to double or triple by 2050. The rapidly increasing production of plastics and the continued reliance on fossil fuels for production, have contributed to numerous environmental problems and health harms. As a result, plastic pollution has become an increasing threat to natural ecosystems, human health and climate. However, there is a lack of granularity on the contribution of the primary plastics specifically to greenhouse gas (GHG) emissions and their impact on the remaining global carbon budget needed to stay below a 1.5°C or 2°C global average temperature rise. In this report, we explore the contribution of primary plastic production to climate change disaggregated by polymer and technology. To this end, we have developed comprehensive bottom-up modeling of GHG emissions from global primary plastic production, with a special focus on polymer value chains. We have analyzed the results under various growth scenarios in the context of carbon budgets compatible with a 1.5°C global trajectory. Modeling includes the material flows of all production stages, processes and technologies used in primary plastic production value chains, including from the extraction of fossil fuels required for production to shaping the final product. We specifically focus on nine major types of fossil fuel-based plastic polymers that are produced and consumed in large quantities: three types of polyethylene (PE) – low-density (LDPE), linear low-density (LLDPE), and high-density (HDPE) – as well as polypropylene (PP); polyethylene terephthalate (PET); polyvinyl chloride (PVC); polystyrene (PS) and other key styrene-based plastics such as styrene acrylonitrile (SAN) and acrylonitrile butadiene styrene (ABS), and polyurethane (PU). Together these account for about 80% of plastics production. Our estimates show that global production of primary plastics generated about 2.24 gigatonnes of carbon dioxide equivalent (GtCO2e) in 2019, representing 5.3% of total global GHG emissions (excluding, agriculture and LULUCF (Land Use, Land-Use Change and Forestry)). Emissions from primary plastic production are generated from the combustion of fossil fuels for process heat and electricity and from other non-combustion processes. Approximately 22%, 21%, and 15% of emissions related to primary plastic production in 2019 come from all PEs together, PET, and PP, respectively. Other key plastics, i.e., PVC, PS, SAN, ABS, and PU are responsible for around 23% of global emissions from plastic production. Most (~75%) GHG emissions from primary plastic production occur from the steps prior to polymerization. Under a conservative growth scenario (2.5%/yr), GHG emissions from primary plastic production would more than double to 4.75 GtCO2e by 2050, accounting for 21-26% of the remaining global carbon budget to keep average temperature increases below 1.5°C. At 4%/yr growth, emissions from primary plastic production would increase more than three times to 6.78 GtCO2e, accounting for 25-31% of the remaining global carbon budget for limiting global warming to 1.5°C. Such detailed modeling of individual primary plastic polymers, where production value chain stages are fully taken into account, can provide a sound technically neutral and scientific foundation to inform the global plastic treaty and enable stronger coordination with other global treaties on climate change (e.g., United Nations Framework Convention on Climate Change (UNFCCC). Such modeling is also critical to understand the climate impacts of proposed mitigation measures under the treaty, as most of these are either polymer-specific or would have different implications per polymer.