With the Oxford Martin Programme on the Future of Plastics coming to an end, we explore how this research programme has helped develop a holistic solution to the challenge of ending plastic pollution, resulting in the concept of a circular economy for plastics.

In March 2022, member states of the United Nations agreed to end plastic pollution and finalise an international legally binding agreement. At the time of writing, this treaty is yet to be agreed – with discussions set to resume in 2025 – but it is expected to be an important tool in addressing this enduring environmental challenge.

Effectively dealing with waste from plastic is a growing problem, especially as the industry continues to grow rapidly. Production has increased from 2 million metric tonnes in 1950 to an estimated 400 million metric tonnes in 2022, with a turnover of over £335 billion. Researchers say the global plastics system results in over 1.7 gigatonnes per annum of greenhouse gas emissions as of 2015 – the same as the combined emissions of UK, Germany and France. If left unchecked, this could rise to 6.5 gigatonnes by 2050. Only 9% of plastic waste of global plastic waste is recycled, with the rest lost to landfilling, incineration or entering land and marine ecosystems.

To help tackle the issue, the Oxford Martin Programme on the Future of Plastics has proposed the idea of a circular economy for plastics. This represents a rethinking of the technical, economic and policy paradigms that have entrenched the status-quo - one of rising carbon emissions and uncontrolled pollution. The researchers, drawn from different academic backgrounds, understood from the outset that an interdisciplinary approach was needed for this complex issue.

‘The question we wanted to address is, “How do we sort out this problem of large-scale plastics pollution, and of course global warming due to the plastic system as well?”,’ Cameron Hepburn, Battcock Professor of Environmental Economics at the Smith School of Enterprise and the Environment as well as a co-director of the Future of Plastics programme, told us.

‘And when you start with the problem rather than with the discipline, you then naturally ask what disciplines do we need to answer the problem. Like if you're building a house, you don't start with a saw, you start with the plan of the house and then you get the carpenters and the masonry and all the bits to be put together.’

Charlotte Williams, Professor of Inorganic Chemistry at the University of Oxford’s Department of Chemistry and director of Future of Plastics, had already been working with her group on how to make plastics more sustainable. She then got together with Professor Hepburn and Emeritus Chichele Professor of Public International Law Catherine Redgwell to develop the Oxford Martin programme, which cut across several critical areas:

• Understanding what is a very complex plastics economy in its current state using greenhouse gases as a key metric, and how to reduce its various adverse impacts.
• Identifying and pushing technologies that could help cut emissions in the manufacture of plastics.
• Examining key legislative frameworks in the context of the plastics system and highlighting their limitations.
• Conducting economic analyses on whether consumers were paying the right prices for fossil-derived carbon based on their greenhouse gas impacts.

Professor Williams knew instinctively that she wanted to work with her two co-directors on tackling the plastics problem due to the vast levels of expertise they had in their respective areas. She saw their collaboration as a huge success due to the high levels of commitment they all demonstrated:

‘Everybody was engaged, they asked questions – it took a long time to learn one another's language. In the intervening period we had COVID-19 going on, but we kept going.

‘And I really think that that was a big part of how we led, how we got this team to the successful outcome. We showed that we really cared and that we didn't know the answers either, but that we had some ideas of where we'd go and find them.’

One wide-ranging answer the researchers did deliver, and which truly embodies the multidisciplinary approach of the programme, was the concept of a circular plastics economy. In their paper published in Nature, they analysed the current and future global plastics system and proposed technical, legal and economic interventions, from now until 2050, to allow it to transition to net zero emissions and reduce other negative environmental impacts. The study included 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 by using only renewable raw materials, including waste biomass, recycled plastics and carbon dioxide.
• For plastics which are recoverable from waste streams, maximising recycling very significantly, targeting 95% recycling.
• Integrating plastic manufacturing and recycling with renewable power and minimising all other negative environmental impacts, including of additives.

‘The raw materials – oil and gas – go into the polymer and then at the end of their life, they either produce carbon dioxide during incineration, are buried in the ground or escape into the environment. In most cases, they don’t return to being a useful raw material,’ explained Professor Williams.

‘When we began to think about our interventions, it was really useful to consider the circular carbon economy – how can we ensure that the carbon atoms are recirculated and recycled efficiently and quickly.’

So, is the circular plastics economy an achievable dream?

‘We actually can do it, but whether we will or not, given the current state of international governance and interest in these issues, is an open question,’ replied Professor Hepburn.

‘So, it's not impossible, but it's very, very hard and there's an awesome amount of work ahead, and not just in the chemistry [side]. We have a great deal of work to do on the legal and the economics sides as well as the business side.’

To exemplify the non-scientific engagement the programme carried out, Professor Hepburn described a related collaboration with Unilever to develop a set of interventions and regulations to spur the fast-moving consumer goods industry, a major user of plastics, to ramp up the deployment of bio-based sources of carbon in their products, in this case cleaning products.

Even though the Oxford Martin programme has come to an end, the researchers are firmly focused on what can be achieved in the future in this critical area.

Professor Hepburn mentioned ongoing engagement around the UN plastics treaty, while Professor Williams will be leading the UKRI-funded Sustainable Chemicals and Materials Manufacturing Hub (SCHEMA), whose research aims to transform the way chemicals and polymers are designed, made, and recycled.

‘The clear outcome from [our paper] is that we need a continued push for change on all fronts – technically, economically and legally. In order to deliver what we've said, we need to work effectively together to ensure the changes are implemented,’ added Professor Williams.

Both were firm that a net-zero future for plastics simply had to happen.

‘The timeline that we propose is very, very tight and requires enormous integrated effort internationally,’ explained Professor Williams.

‘It simply has to be because the alternative is disastrous for humanity. It's disastrous for the economy and it's disastrous for a whole range of downstream, future technologies of this industry.’

She added that independent research that continued to educate and engage with stakeholders would be critical, and offered hope for the future.

‘We will continue to advocate to leaders in business, finance, government and international organisations that this area is incredibly important and cannot be overlooked. So, am I optimistic? Yes, but I'm also concerned that the world wakes up to the challenges we must solve in this sector – it’s about much more than merely recycling.’

Professor Hepburn agreed that achieving net-zero in plastics by 2050 was a difficult ask.

‘That's 25 years away – that's not that long really to change what is a massive global industry in all of the value chain, from the start to the end,’ he said.

‘If you forced me to take a bet with 50/50 odds, I'd be betting against it right now. But will we do it at some point? Absolutely.

‘We can't keep going on like this. So, whether it's 2050, or 2060, or later, it'll happen.’

This opinion piece reflects the views of the author, and does not necessarily reflect the position of the Oxford Martin School or the University of Oxford. Any errors or omissions are those of the author.