Greenhouse gas removal with UK agriculture via enhanced rock weathering

Meeting the UK's obligations for net-zero carbon emissions by 2050 requires capturing and storing residual emissions of approximately 130 million tonnes of CO2e (CO2 equivalents) yr-1 with greenhouse gas removal (GGR) technologies within decades. The challenge is to achieve stringent mid-century emissions reductions without incurring major economic costs. Enhanced rock weathering (ERW) is a GGR technology based on amending soils with crushed calcium- and magnesium-rich silicate rocks to accelerate natural CO2 sequestration processes, whilst delivering co-benefits for crop production, food security and soil health.

This ERW-GGR Demonstrator will provide the first integrated whole system assessment of the science, societal and scalability opportunities and challenges of ERW deployment in UK agriculture. It will assess the potential of ERW to remove up to 10% of the UK's GGR net-zero target by testing its implementation on arable land and the types of grassland covering 74% of UK utilized agricultural area (~13 million ha). Potential co-benefits include improved productivity by reducing excess soil acidity, resupplying soils with depleted plant-essential mineral nutrients, increased crop resistance to pests and pathogens, via greater silica uptake, and reducing soil nitrous oxide fluxes. Quantification of these co-benefits will generate evidence for catalysing early adoption and accelerating development pathways into standard agricultural practices.

We will address the challenge of developing ERW-GGR with crushed silicate rock (basalt) through a creative, innovative and exciting cross-disciplinary collaborative programme comprising four interlinked Work Packages: WP1) large-scale sub-catchment, field or plot trials representing major UK land uses, including full GHG budgeting, WP2) public engagement, social acceptability and responsible innovation of ERW as a GGR technology, WP3) supply chain Life Cycle Assessment and scalability case studies road-mapping deployment scenarios 5 and 15-20 year post-Demonstrator, and WP4) development and application of an advanced modelling framework for realistic assessment of GGR with UK agriculture and its impact on farm economics.

The ERW Demonstrator will be developed across three nationally important flagship field sites with long-term baseline datasets. The Plynlimon Experimental Catchments (mid-Wales) form the UK's longest-running catchment research facility, with 40 years of monitoring data from two paired catchments dominated by upland grassland with sub-catchments on the same bedrock and soils. In England, we will utilize two core BBSRC facilities: Rothamsted Research's North Wyke grassland experimental platform, Devon, and their cutting-edge arable research facility in Harpenden. Our interdisciplinary programme integrates across the natural and social sciences, with the former identifying environmental benefits and risks of deployment on UK arable and pastureland, and the latter contributing in-depth knowledge of public perceptions and local community acceptance of ERW. Working across WPs, we will construct a social license for ERW to operate at-scale in UK agriculture and develop a Responsible Research and Innovation programme for the Demonstrator.

We are planning three Demonstrator-led events, Policy Briefings, and outreach events with the Agriculture and Horticulture Development Board, to facilitate academic, business and policy interactions and ensure regular contact with the wider stakeholder communities. Our work includes in situ work with stakeholders and gatekeepers to fill in the current cultural and social background of local rural communities, followed by in-depth deliberative research regarding ERW proposals with community members. The team will work with pre-existing community initiatives at each site, e.g., Welsh Government funding at Plynlimon and Defra funding of Rothamsted for linking conservation with land management changes.