The UK’s inventory of greenhouse gas emissions measures progress towards reduction targets. The methodology for agriculture has recently changed to better reflect the current science on the GHG emissions from agriculture.

The new methodology is called the ‘smart inventory’. It includes a wider range of technologies and management options than the previous inventory based on more recent science, although there are still gaps in our understanding.

This report summarises how different changes to  agricultural practice in Scotland are (or could be) recognised in the smart inventory. It provides information to policy makers on what changes can be captured in the UK GHG inventory, and what further steps could be taken to reflect Scottish agricultural practices more accurately.

Key findings

  • The smart inventory reflects the mitigation activities for which we currently have robust data and analysis
  • Annual Scotland-specific data are used in many activities (e.g. crop areas, fertilisation rates livestock numbers, milk yield, slaughter weight), but more specific activity data either are either not updated annually or not systematically collected for Scotland.
  • Inventory development is a continuous process and future data collection should be planned with the Inventory team in order to maximise the use of the data in the inventory. 
  • There are four main data categories that would enhance data collection initially:
    a) Nitrogen fertilisation of minor crops and novel legumes 
    b) Area and fertilisation information on  intercropping
    c) Ruminant diets
    d) Manure management and storage information

Farm-based carbon audits are one of the tools that might help reduce greenhouse gas emissions in the farming sector. This report compares the available tools to assess their potential application in Scotland.

Key findings:
  • 64 potentially applicable tools were identified through a web search. Of these, nine were selected for more detailed comparison. Analysis found that a further six were not suitable due to a variety of shortcomings (e.g. general purpose of the tool, major limitations in comprehensiveness, lack of transparency).
  • Only three of those tools would be suitable for farm level carbon audits in Scotland:
    1. AgRE Calc
    2. Cool Farm Tool and
    3. Solagro (JRC) Carbon Calculator
  • These tools follow a similar calculation framework (international guidelines and international calculating standards), although none can be judged to be fully comprehensive. Although currently free to use, maintenance and development of the carbon audit framework requires continuing investment. In addition, their application needs to be embedded in wider environmental and farm context in the form of advisory support (i.e. the tool should not be the sole information source for decision).
  • The comprehensiveness and practicality of each tool varies between production systems (e.g. crop production, livestock production, carbon sequestration). No tool is fully comprehensive, and each can only handle a limited amount of possible emissions reductions on farms. None of the three recommended tools considers embedded emissions in livestock bought in.

This project looked at improving the measurement of the GHG emissions intensity of the main agricultural commodities at a national level. 

The Scottish Agricultural Emissions Model (SAEM) calculates the amount of commodity produced per herd/flock or per hectare of crop and the GHG emissions arising from this production. The emissions intensity of the commodity can then be calculated.

SAEM complements the UK GHG Inventory by providing estimates of the emissions intensities of the main agricultural commodities in Scotland. SAEM uses the IPCC’s widely accepted and transparent Tier 2 approach to calculating GHG emissions, which has a clear scientific rationale as is consistent with the UK GHG Inventory approach.

Using SAEM does require a moderate knowledge of MS Excel and some familiarity with agricultural processes and the emissions arising from them. SAEM is therefore not intended for use by the layperson or occasional user but provides experienced users with significant scope for investigating the drivers of agricultural emissions.

This report looks at options for reducing the greenhouse gas emissions from Scottish Farms. It analyses a range of options across changes in management of fertiliser, soil and manure, livestock feeding and energy use. Some of these changes require an investment in new tools, equipment or other installations on farm.

The analysis indicates that the 20 technology options considered could reduce emissions by between 9 and 150 kt CO2e GHG annually if they were implemented to their fullest potential across Scotland. Doing this would also have other positive environmental effects (e.g. with regards to soil or water quality).

The report recommends use of complementary incentive mechanisms to encourage uptake of the technologies. These could include:

  • increased emphasis on these technologies in extension services or mechanisms;
  • support for collaborative implementation of the technologies;
  • foot printing/accounting schemes for validating and signalling on-farm and supply chain progress; and
  • a comprehensive approach to each stage of the supply chain.

Methane emissions from livestock are responsible for approximately 50% of the greenhouse gas (GHG) emissions associated with agriculture in Scotland. Reducing the emissions is key to reducing agricultural emissions in Scotland. 

We have looked at this issue from different perspectives:

  1. Review of options for reducing greenhouse gas emissions via cattle slurry management
    explores how to reduce the greenhouse gases from storing and use of slurry at Scottish farms
  2. Livestock Health & Greenhouse Gas Emissions– looking at how emissions intensity could be reduced through control measures relating to
    • milk yield and cow fertility rates (dairy systems),
    • cow/ewe fertility and abortion rates, calf/lamb mortality and growth rates (beef and sheep systems), and
    • feed conversion ratios, FCR (all systems)
  3. Benchmarking the emissions intensity of Scottish livestock – making recommendations for benchmarking cattle milk and meat, and sheep meat within the boundary of cradle to farm-gate, in the first instance.
  4. Nutritional strategies to reduce enteric methane emissions –  finding that three of the 12 nutritional strategies evaluated could be effective in reducing enteric methane  emissions. Based on this work, we were asked to explore the practical feasibility of including lipids and nitrates in livestock diets and concluded that this option has limited potential due to the complex connection between feeding regime and emissions.
  5. Farmyard Manure and Slurry Management, and Anaerobic Digestion in Scotland – Practical Application on Farm: this report examines the market potential for anaerobic digestion technologies as a tool to manage slurry and farmyard manure arising from Scottish livestock farming, focusing on how greenhouse gas emissions might be reduced.
  6. Slurry Storage on Scottish Farms –  A Feasibility Study – This work assesses the relative value of different slurry management options for reducing greenhouse gas emissions from livestock production.  It examines key sectors where there are significant emissions considers the opportunities for mitigation.