Modelling the current and future greenhouse gas emissions and wider impacts in the Scottish beef, sheep and dairy sectors

Challenges

One of the most important policy goals for agriculture and land use in Scotland is to reduce their environmental impacts (including greenhouse gases (GHG), reactive nitrogen, and biodiversity damage) while transitioning towards net zero by 2045 and providing wider environmental benefits. The harmonised and integrated policies needed for this transition necessitate analytical capacities which span from the national scale to the farm level and encompass the range of policy goals, providing tools for policymakers to explore various future scenarios.

Advances in integrated modelling and analytical methods in recent decades and the rapid evolution in large-scale disaggregated data availability make the development of spatially detailed research tools possible. However, while various tools exist already in the domain of the environmental impacts of agriculture and land use, bespoke national-level tools to explore future greenhouse gas emissions and wider impacts in Scotland have only been developed as relatively narrow investigations and without a strong capacity to utilise spatially disaggregated input data.

Questions

Solutions

The overall aim of this project is to understand how pre-farm and on-farm emissions of ruminant and wider food production could be reduced and what would be the cost-effectiveness of such efforts. The focus is on enhancing our analytical capacity to robustly estimate agricultural emission reduction pathways from the holding to the national scale. We are covering ruminant systems, given their importance in Scottish agriculture and their impact on GHG emissions. However, the tools and analyses we develop include the wider resources used on livestock farms.

Identifying key policy questions 

We are working with policymakers in the Scottish Government and industry representatives to identify the key questions which need to be answered in the short- and mid-term about the GHG emissions from ruminant production and the related land use as an integral part of Scottish agriculture. The specific data and methods prioritised are determined by the identified key questions.

Developing an integrated model 

We are designing a model to generate outputs to answer policy questions. This tool estimates current and explores future GHG emission scenarios and the cost-effectiveness of solutions in Scottish agriculture, regarding both farm boundaries and pre-farm emissions and wider environmental impacts. The material flows included are those most important in agricultural production: feed, fertiliser and energy inputs, crop, milk, and meat outputs and GHG emissions. Specific wider environmental impacts are being integrated into the work, namely an exploratory representation of GHG, ammonia emissions, land use, and a proof-of-concept work on assessing the biodiversity effects of mitigation actions on farms. Inputs, algorithms, and outputs have close comparability with the UK GHG Inventory and with on-farm carbon calculators.

Modelling current emissions and future emission pathways

GHG reduction pathways

The need to achieve significant GHG reduction in Scottish agriculture is increasing with the 2045 net zero GHG goal approaching. This requires an assessment of alternative scenarios for land use, agricultural production profiles and farm practices. We are firstly using existing models to assess GHG mitigation cost-effectiveness then the new model will be used for an updated assessment of scenarios.

Reducing emissions by improving animal health and nutrition of ruminants

Improving livestock health and nutrition is a key contributor to reducing GHG emissions from animal agriculture. Sheep and cattle health, ruminant nutrition and ruminant feed additives feature in the most recent marginal abatement cost curve models for Scottish agriculture and stakeholder reports. In collaboration with key industry stakeholders, the health modelling prioritises the production diseases and syndromes that have the greatest impact on the carbon footprint of Scottish livestock farming. It identifies relevant datasets to help quantify the impacts of priority diseases and syndromes affecting livestock production in Scotland. The work explores practical intervention strategies that have the biggest impact on disease control and quantify the GHG emissions and production impacts of them.

Synergies and trade-offs between GHG emissions and biodiversity in ruminant systems

A proof-of-concept investigation explores potential routes to integrate biodiversity metrics within larger-scale co-modelling. Such modelling enables us to explore the potential co-benefits of land use and crop change on biodiversity conservation and the reduction of GHG emissions. We build upon previous work that integrated crops, habitats, agricultural production, and biodiversity modelling to generate estimates of pollinator abundance for land categories derived from the ecoinvent database.

Guidelines to bridge the three levels of GHG modelling in Scotland 

We are also delivering a suite of protocols and methods enabling us to bridge three key levels of GHG accounting in Scotland: i) the Scottish emissions in the UK GHG Inventory, ii) the projection and scenario exploration of Scottish emissions and iii) farm-level emission accounting.

Overall, this project is enhancing the analytical capacity to robustly estimate agricultural emission reduction pathways. It is equipping the Scottish Government with information to move towards establishing a whole-farm approach to emissions accounting on Scottish farms. This approach is comparable with the UK GHG Inventory and informed by the constantly improving scientific evidence on mitigation options.