Oxford Chemists Collaborate on Roadmap for Circular Carbon and Plastics Economy

Researchers from the Department of Chemistry including Trinity’s Charlotte Williams have outlined ambitious targets to help deliver a sustainable and net zero plastic economy.

In a paper published this week in Nature, the group of researchers from the Oxford Martin Programme on the Future of Plastics, argue for a rethinking of the technical, economic, and policy paradigms that have entrenched the status-quo, one of rising carbon emissions and uncontrolled pollution.

Currently the global plastics system results in over 1 gigatonnes per year of carbon dioxide equivalent emissions which is the same as the total combined emissions of Europe’s three largest economies (UK, Germany and France). If left unchecked, these emissions could rise to 4-5 gigatonnes per year and intensify other forms of pollution. Another problem is the lack of effective recycling – in 2019, only 9% of the world's plastic waste was turned into new products through mechanical recycling. The majority ended up in landfills or was incinerated, and a significant proportion was mismanaged, ending up polluting terrestrial and marine ecosystems.

The authors analyse the current and future global plastics system, proposing technical, legal, and economic interventions from now until 2050 to allow it to transition to net zero emissions and to reduce other negative environmental impacts. The study includes a future scenario centred on four targets:

• Reducing future plastics demand by one half, substituting and eliminating over-use of plastic materials and products.
• Changing the way plastics are manufactured to replace fossil fuels as the hydrocarbon source to use only renewably raw materials, including waste biomass and carbon dioxide.
• For plastics which are recoverable, maximising recycling very significantly, targeting 95% recycling of those materials which are retrievable from wastes.
• Integrating plastic manufacturing and recycling with renewable power and minimising all other negative environmental impacts, including of additives.

The authors emphasise the need for concerted action across all four target areas to ensure the global plastics systems curbs its climate impacts and meets UN Sustainable Development Goals.

Lead author Professor Charlotte Williams from the Department of Chemistry is Professorial Fellow at Trinity College; she notes: ‘We need plastics and polymers, including for future low emission technologies like electric vehicles, wind turbines, and for many essential everyday materials. 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 the plastics 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.

Professor Williams’ research group is actively engaged in developing innovative solutions to meet this goal. A particular focus is to investigate techniques that can manufacture plastics from abundant renewable resources (such as carbon dioxide, biomass or industrial wastes), rather than petrochemicals.

She says: ‘I undertook part of my training 20 years ago in the USA where they were making the first commercial bio-derived plastics. Seeing how well these materials performed was very inspiring. This led me to explore how to make sure these ‘alternative’ materials meet all the property specifications and application needs we have, but with a designed end-life fate and energy efficiency throughout their lifecycles.’