Farm Business Survey 2021-22: Farm level emissions and nitrogen usage

Measuring farm greenhouse gas (GHG) emissions

Agriculture and food production rely on natural processes and consequently will always cause a degree of greenhouse gas emissions.  

Definitions

Greenhouse gas (GHG) emissions are measured by:

• Absolute gross GHG emissions (tonnes CO2 equivalent per hectare)
• Emissions intensity (kg CO2 equivalent per kg of output)

These indicators measure GHG emissions from farm production activities. They do not account for any sequestration by woodland areas or soil.

Absolute gross emissions measures the GHG emissions from a unit area of agriculture land (hectare).

Emissions intensity measures the carbon footprint of a unit of product up to the farm gate. It includes all types of agricultural products produced on the farm.Data collected through the Farm Business Survey provide a consistent and high quality input data set about farm activities. GHG emissions are then estimated using a carbon footprint calculator tool (Agrecalc). It is based on the life cycle assessment (LCA) framework for estimating emissions from products and processes. The LCA accounts for emissions up to when product leaves the farm. The tool uses the latest IPCC Tier I and Tier II as well as national figures from the UK National Greenhouse Gas Inventory in its calculations. It is PAS2050:2011 certified. Different results may be obtained using different carbon calculators or different methods, for example using an inventory approach.

There are three main greenhouse gases produced in agriculture. These are carbon dioxide, methane and nitrous oxide. Total emissions are presented in carbon dioxide equivalent (CO2-e) units. This takes into account the different effects that the different gases have on climate change, known as their global warming potential (GWP). Over a 100-year period, methane’s GWP is considered to be 25 times stronger than that of carbon dioxide, while nitrous oxide’s GWP is considered to be 298 times stronger than carbon dioxide.

Results are shown for the average (median) farm and as such are not directly comparable to results published on farm income. Error bars show the upper and lower quartiles and demonstrate the variability of emissions.

More information can be found in Data sources and more information.