Creating a carbon-negative future for polymers and plastics

20 October 2021

Portrait of Professor Cameron Hepburn

by Professor Cameron Hepburn
Battcock Professor of Environmental Economics

Cameron Hepburn is co-Director of the Economics of Sustainability Programme, based at the Institute for New Economic Thinking at the Oxford Martin School. He is the Battcock Professor of Environmental Economics at the Smith School of Enterprise and the Environment, which he directed from 2018-2023.

Adobe Stock 282311361
Carbon-based products, such as plastic and polymers, pharmaceuticals, and fertilisers, are indispensable components of modern economic and social systems. Traditionally, this carbon has been sourced from petrochemicals.

The annual demand for polymers continues to rise every year, meaning more and more carbon will be needed to make these polymers. However, to reach a net-zero greenhouse gas emissions (GHG) world and stem the worst effects of the climate crisis this will create serious challenges.

I recently co-authored a report titled ‘Industrial need for Carbon in Products’ with Katherine Collett, Mike Mason, Charlotte Williams, Matthew Davidson, and Brian O’Callaghan. It was published as part of a series of reports aiming to identify key technological solutions for the final stages of the essential transition to net-zero, and then net-negative, CO2 emissions. The series looked at the 20% of global emissions perceived to be the most difficult to decarbonise and solutions to achieving 5% net-negative CO2 - the ‘Final 25%’. The fossil carbon used in plastics and polymer manufacturing is this sort of ‘hard to abate’ challenge.

This report details that research and development is essential in order to achieve sustainable zero-emissions carbon for use in products and identifies key priorities for this R&D work. We need biodegradable polymers made from non-fossil carbon, so we need to both develop them and identify suitable feedstocks from which to manufacture.

Part of this will not only be identifying the plant-based or captured CO2 feedstocks that are the best options for making the polymers we need at scale. But also that the polymers they make are as close to possible in properties and performance as the petrochemical derived polymers they are replacing, and that we have the technology to recycle them better.

Mechanical recycling – the most common form of recycling we use today, where plastics are cleaned and melted down to create new products – is relatively cheap and scalable, but vulnerable to contamination and the finished product is of worse quality than new plastic and suitable for fewer uses. The main alternative is chemical recycling in which the waste material is broken back down into its chemical ‘building blocks’, which can then be reused to polymers that are as good as new. We are currently making progress on ways of chemically recycling existing polymers and plastics, but when developing new polymers we can design them to be both biodegradable and chemically recyclable before deploying them at scale.

A lot of what we need to begin along this pathway to a net-zero polymer and plastic industry relies on government action. The report states, “policy and regulation will play major roles in increasing the global recovery and recycling rates of waste products, and in supporting early-stage investment in R&D of sustainable alternatives to fossil carbon.”

Public financing is needed to accelerate the development of plant-based polymers until scalable and financially viable options have been developed. We also need incentives to drive the recovery and recycling of existing plastics and polymers in the meantime, to slow demand for petrochemical feedstock and reduce the long-lived plastic waste sitting in landfills or floating through our rivers and oceans. Finally, we need standards and targets for industries that create and use polymers to provide a ‘push’ for the transition to sustainable polymers. These standards could start with what is currently viable and get stricter over time until we have achieved the decarbonisation of that final 20% and pushed into a carbon-negative future for plastics and polymers.

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.