Researchers at the University of Oxford have published a roadmap for a circular carbon plastics economy by 2050. They considered four scenarios: (1) baseline, (2) business-as-usual, (3) conservative commitments, and (4) bold system change.
For each scenario, the team estimated the consequences for greenhouse gas (GHG) emissions and recirculated carbon content of four mitigation strategies: reducing plastic consumption, increasing recycling rates, replacing fossil carbon with renewable alternatives, and powering manufacturing and recycling processes with renewable electricity.
Results show that only the bold system change scenario achieves a net zero plastics economy by 2050, requiring future plastic demand cuts of 50% from expected levels, complete phase-out of fossil-derived plastics, 95% recycling rates of retrievable plastics, and 100% use of renewable energy.
The authors are aware this scenario ‘requires some very substantial changes to current practices’. They mention the high costs of bioplastics and carbon capture technologies as ‘current key barriers’.
“States can provide financial subsidies to allow manufacturers to sell such plastics at lower cost, driving production at scale,” the academics suggested. “Global growth of renewably sourced plastics could rapidly increase from about 4% to 10%–20% if their adoption was subsidised and politically supported, similarly to contracts for difference used to grow low-carbon (emissions) energy. Public-private partnerships that bring together the expertise and resources of several stakeholders can accelerate innovation and advance cost reduction for nascent bio-based industries.”
In comparison, the ‘business-as-usual’ scenario shows rates of incineration and recycling reaching up to 50% and 43%, respectively. The carbon footprint remains over 2.5-fold higher than the level of today and surpasses 4.0 GtCO2 a year, not far from the projected baseline.
“This scenario reveals a key message: augmenting recycling of plastics waste alone (approximately 40% of recirculated carbon) is simply not enough to tackle the emissions crisis,” the authors noted.
“We need plastics and polymers, including for future low emission technologies like electric vehicles, wind turbines, and for many essential everyday materials,” said lead author Professor Charlotte Williams. “Our current global plastics system is completely unsustainable, and we need to be implementing these series of very bold measures at scale, and fast. This is a solvable problem but it needs coherent and combined action, particularly from chemical manufacturers.”
To successfully transition to a circular system, the authors set out principles to ensure ‘smart materials design’ and differentiate between plastics which are recoverable and irretrievable after use, noting that there is not a one size fits all solution. Rather, the authors propose careful use of the design principles to help select the optimum production methods and appropriate use of resources, deliver the required performances, ensure waste management, and minimise broader environmental impacts. A timeline of technical-economic-policy and legal interventions helps readers focus on the actions needed to reach net zero emissions by 2050.
The team shared their findings in ‘Designing a circular carbon and plastics economy for a sustainable future,’ recently published in nature.