The Stoner Colloquium

The School of Physics and Astronomy are delighted to host Professor Anthony J. Ryan, OBE for this year’s Stoner Colloquium.

About the colloquium

Tony is a Professor of Physical Chemistry at the University of Sheffield and the founding Director of the Grantham Centre for Sustainable Futures. Tony will be joining us to give a talk on:

Neofossils: biogenic plastics to sequester CO2

In the last 50 years more than 8 billion tons of the stuff vilified as “plastic” has been produced because their ubiquity and variety mean they are completely embedded in our lives. And lots of the enabling research was done in the Leeds Physics Department. But the very properties of plastics that make them so useful, they are durable & cheap, also mean that they are almost worthless post-use, expensive to recycle & easy to discard.

We have been focussed on delivering a circular economy for polymers, whether they are derived from fossil carbon or more recent biomass. A systems-based, multidisciplinary approach should be able to solve the problem of plastics in the environment through a combination of reuse, repurposing & recycling – and yet recycling rates are stuck at ~10% globally and falling in many places. This work has led us to the conclusion we need to turn the problem on its head. Make more single-use plastic but using C that has been fixed by photosynthesis and taken from the atmosphere this year, not C fixed millennia ago. Neo-carbon not fossil-carbon to turn into neo-fossil plastic and put it back in the ground through curated burial - the emphasis being on curation and preventing leakage.

The current emphasis on bio-based & compostable plastics is not inherently sustainable because their production can cause more greenhouse gas emissions than the fossil-based plastics they replace. Moreover, the fate of a compostable plastic is conversion back into CO2 & water. Bio-based plastics can only become truly sustainable when produced using renewable energy, not the current energy mix of >70% fossil. Life cycle assessment can identify the tipping point, as the energy system defossilises, when making durable bio-based plastics makes sense.

The petrochemicals industry could continue to benefit from its capital assets and be persuaded to leave the oil & gas in the ground if it could see a profit from a "consume then conserve" plastic policy. When plastic sequesters carbon from the atmosphere by being made from biomass it makes sense to use it to replace even more materials. For example, carbon fibre composites (where both the fibre & the resin were neo-carbon) could replace lightweight metals in transport and steel in construction.

We could use durable (i.e. nondegradable) biogenic plastics to sequester carbon. Making polymers from photosynthetic biomass takes CO2 out of the atmosphere and we could bury that plastic. In fact, if we converted all the current 400 million tonnes of annual plastic production to non-degradable bioplastics, using 100% renewable energy and agricultural waste as the feedstock, we would be able to remove 1 billion tonnes of CO2 from the atmosphere every year and help deliver the Paris climate change goals. 

Book your place

The lecture will take place in the Michael Sadler Building at the University of Leeds, with the colloquium commencing at 5.00pm in the Rupert Beckett Lecture Theatre (LG.X04) and the drinks reception commencing at 6:00pm in the Michael Sadler Foyer. 

Booking is required to attend this event – you can do so at our dedicated ticket portal.

If you have any questions, please contact Physics.Research@leeds.ac.uk.