by Becky Wilson
Why should carbon be measured?
The old adage of ‘you can’t manage what you can’t measure’ is certainly true of carbon accounting. But when it comes to agriculture, measuring carbon isn’t as simple as it may first seem.
The variations in emissions and carbon stocks are because they are based on measuring biological systems, which are impacted by climate, soil type, topography and vegetation, as well as what farmers are doing in terms of land management. Which makes the whole thing a little tricky. However, undaunted by this complexity, carbon metrics are an essential tool that farmers can use to not just identify climate solutions, but also to baseline the farm’s emissions and hence, drive technological change.
Identifying the carbon footprint of a farm business is the first vital step in being able to quantify the contribution that the farm is making to climate change. A carbon footprint calculation identifies the quantity and source of carbon dioxide, methane and nitrous oxide emitted from the farm (plus carbon sequestered in soils and woodland), highlighting areas where improvements or changes can be made to reduce greenhouse gas emissions.
Greenhouse gases are much talked about, but they are inherently intangible. They can’t be seen, tasted, heard or touched; and they are all gases that are released in relatively small quantities on a continuous basis. So how can a farmer fully understand what is going on with them and how can comparisons be made?
Reducing carbon emissions in a farming business makes sense on many levels. High carbon emissions tend to be linked to high use of resources, and/or wastage, so reducing emissions also tends to reduce costs. This makes the farm more efficient and should improve profitability. As well as the business opportunities that come from reducing emissions, farmers and landowners are in the unique position to be able to sequester carbon in trees, hedgerows and margins and within the soil.
Before acting to reduce emissions, it is necessary to first understand where the emissions are coming from. Are the largest emissions coming from livestock, soils, fuels, or fertilisers? It is vital to get a picture of the farm business – and this is made possible by carbon footprinting.
Choosing a tool to use
There are various carbon footprinting tools that have been designed for use by individual farmers (or groups of farmers) interested in understanding what is happening ‘on-farm’.
Although the often-held belief is that there are many tools to use, in reality there are four main options which are available to all UK farmers and growers who are keen to start footprinting; these are the Farm Carbon Calculator, AgreCalc, the Cool Farm Tool and Sandy.
There are other footprint calculators; however, these aren’t universally available, and are used specifically within a supply chain (for example, within the dairy sector). The golden rule is, once a farmer has decided what tool to use, stick with it, as there are differences within the methods used in each calculator, so comparing results between calculators is meaningless.
Although the simple principle of completing a carbon footprint assessment is the same (emissions minus sequestration equals footprint), there remains some variation between the scope and boundaries that the tools use to calculate the results. Boundaries of a calculation determine what aspect of production is being assessed; for example, whether the emissions associated with one farm enterprise or the whole farm are being calculated, or whether it is assessing operations within the farm gate or taking account of what happens off farm.
A key part of selecting the tool to use centres around what the carbon footprint is used for:
- As a marketing tool – if farmers are wanting to use the results for marketing purposes, it is a good idea to choose one that has a clear method attached to it, and which sets out what is included and excluded from the calculations. There are also potential commercial benefits, particularly where financial rewards for decarbonisation are involved. In this way, the carbon credentials are completely transparent
- As a management tool – if the results and the data are to be used as a management tool, perhaps to highlight areas to improve in the future, then the tool needs to be able to evaluate the impact of changing the management of the areas being assessed. These tools tend to need more data to be added in at the start, so that the impact can truly be seen
- For interest – if a farmer is simply interested in what might be happening in carbon terms on the farm, then again choosing one that explains clearly what is included and omitted, and shows the footprint broken down into key areas is a good starting place
Carbon sequestration – in or out?
A key question to look at when footprinting is whether carbon sequestration is included in the calculation. Carbon captured within trees, hedgerows and field margins as well as the carbon held in soil is an important part of the footprint and shouldn’t be overlooked. If the tool doesn’t include sequestration, then the footprint will look at the negative without assessing the positive.
One of the challenges facing carbon calculators which are working at supply chain or enterprise levels is the ability to include sequestration as part of the calculation. It is much harder for these approaches to include the opportunity that farmers have to store carbon on the farm, as they are aligned with only one aspect of production on the farm.
Getting started
Once the tool has been chosen, the first step is to gather all the input data. This includes information on fuel use, livestock numbers, fertiliser inputs, use of materials and waste produced. To be accurate, the assessment needs to be comprehensive. The list can look daunting at first, but if the record-keeping is reasonable, then this process should be achievable in a couple of hours. Once this exercise has been completed, the next time will be quicker.
Once the data has been gathered, it’s simply a case of entering it into the calculator, which shouldn’t take more than an hour. The calculator should then produce a breakdown of carbon emissions by sector, both in amounts (kilograms or tonnes of CO2e ) and percentages of the total footprint by category. Armed with this data, it is then possible to consider how to reduce emissions and increase sequestration.
When a regular assessment is made, the direction the farm is moving in starts to become clear and it is easier to see whether the actions taken are working.
Emissions sources
Although each farm will vary in its carbon footprint. Below shows the average breakdown of emissions across a typical livestock and arable farm.
Next steps
Once the carbon footprint of the farm has been worked out, deciding what to do is the next step. The footprint result will be reflected as a carbon dioxide equivalent but should also show where emissions of nitrous oxide and methane are produced. Key areas to focus on are the management of soils, fertilisers, manures, livestock, cropping, energy and fuel.
There are numerous opportunities to reduce both emissions and costs. This leads to improved resilience and profitability, as well as opportunities to improve carbon sequestration and soil health – the ultimate resilient business model! Absorbing more carbon than the farm emits is a goal that all farmers could work towards and understanding the farm’s current carbon position by footprinting is the first key step.
The spotlight is being well and truly shone on agriculture’s carbon credentials. This offers an opportunity for the sector to take the first step and understand what is happening on individual farms, and what can be done to improve profits, reduce emissions and build soil health and sequestration.