A major new study shows adding rock dust to UK agricultural soils in place of imported fertilizer could remove between 6 and 30 million tonnes of carbon dioxide (CO2) from the atmosphere annually by 2050.
The study, led by the Leverhulme Centre for Climate Change Mitigation at the University of Sheffield and partners including The Open University (OU), provides the first detailed analysis of the potential and costs of greenhouse gas removal by enhanced weathering in the UK over the next 50 years.
The study estimates that rock dust can substitute for expensive imported fertilizers. By reducing demand for imported fertilizers, using rock dust avoids carbon emissions and offsets costs of deployment.
Costs of carbon removal are estimated to be around £200 per tonne of CO2 currently, falling to half that by 2050 – making it highly competitive relative to other carbon dioxide removal options.
This technique could make a major but overlooked contribution to the UK’s requirement for greenhouse gas removal in the coming decades with a removal potential of 6–30 million tonnes of carbon dioxide annually by 2050. This represents up to 45% of the atmospheric carbon removal required nationally to meet net-zero greenhouse gas emissions alongside emissions reductions.
Dr Philip Holden, Senior Lecturer in Earth System Science at the OU and co-author of the paper, highlighted the importance of the research:
“Immediate and substantial reductions of greenhouse gas emissions are essential to stabilise climate change, but to keep warming at relatively safe levels, carbon dioxide removal strategies will be needed alongside.”
The recent IPCC Working Group III report released this month made clear that the world, including the UK, will require atmospheric Carbon Dioxide Removal (CDR) strategies, alongside emissions reductions, to mitigate future climate change.
The UK is committed legally to net-zero greenhouse gas emissions by 2050 and requires assessment of all possible CDR options.
Neil Edwards, Professor of Earth System Science and co-author of the paper, commented on the urgency of climate action:
“To meet our climate protection pledges we now need to move forward with detailed plans for both emission reduction and also direct carbon removal with techniques such as enhanced rock weathering that we can deploy immediately.”
A clear advantage of this approach is the potential to deliver major wins for agriculture in terms of lowering emissions of nitrous oxide, reversing soil acidification that limits yields and reducing demands for imported fertilizers. The advantages of reducing reliance on imported food and fertilizers have been highlighted by the war in Ukraine that has caused the price of food and fertilizers to spike worldwide as exports of both are interrupted.
Dr Euripides Kantzas of the Leverhulme Centre for Climate Change Mitigation at the University of Sheffield and lead author, said:
“By quantifying the carbon removal potential and co-benefits of amending crops with crushed rock in the UK, we provide a blueprint for deploying enhanced rock weathering on a national level, adding to the toolbox of solutions for carbon-neutral economies.”