The 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 is not as simple as it may first seem. Carbon accounting systems were designed to measure industrial processes; when measuring the emissions associated with a product manufactured in a factory, we are able quite simply to understand how the inputslead to the outputs and it tends to all be neatlycontained with a building. This is not the case when we usethese metrics to measure farming systems.
On-farm we are trying to measure biological systems, which are impacted by climate, soil type, topography, and vegetation, as well as what we, as farmers, are doing in terms of our management, which can make the whole thing a little tricky! However,undaunted by this complexity, carbon metrics are an essential tool that farmers can use to identify climate solutions, and to baseline the farm’s emissions and drive technological change.
Identifying the carbon footprint of a farm businessis the first vital step in being able to quantify the contribution that the farm is making to climate change. A carbon footprint calculation in its simplest form identifies the quantity and source of carbon dioxide,methane and nitrous oxide emitted from the farm (the emissions) and subtracts from the emissions the carbon that is being sequestered on-farm (sequestration) to providea carbon balance. This balance is the starting point which should then highlight areas where improvements or changes can be made to reduce emissions and improve sequestration potential.
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 both in trees, hedgerows and margins and within the soil.
Before being able to reduce emissions, you need to know 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 business which is made possible by carbon foot printing.
Choosing a tool to use
There are various carbon foot printing tools that have been designed for use by individual farmers (or groups of farmers) who are interested in understanding the carbon balance of farms. Tools include the Cool Farm Tool, AgreCalc, and the Farm Carbon Calculator. The golden rule is, once the decision has been made on which tool to use, stick with it, as there are differences within the methods used in each calculator, so comparing results between them is meaningless.
Although the simple principle of completing a carbon footprint assessment is the same there remains variation between what scope and boundaries the tools used to calculate the results. This is good to understand before starting the process of calculating a carbon footprint. Boundaries are an important factor to consider (or understand with the tool being used) as it makes a difference on the data that you need to collect and also the results. Put simply, boundaries refers to where you are drawing the line around what is included in your calculation and what is not. For example, do you want to calculate the emission associated with one farm enterprise or the whole farm, or just what is happening inside the farm gate or further afield? Making sure this is clear before starting makes the whole process easier. It is important to understand the scope of the calculations– which relates to the level of processes which are included in the calculation, for example – is the tool including emissions associated with electricity production? This is important when producing renewable energy on-farm or using a renewable tariff. It also deals with how the emissions associated with fertiliser production are assigned.
A key part of deciding which tool to use centres around how the footprint is going to be used:
Marketing – if using the results for marketing purposes, it is a good idea to choose one that has a clear method attached to it, which sets out what is included and excluded from the calculations – that way you can be completely transparent about your carbon credentials.
A management tool – if planning on using the results and the data as a management tool, perhaps to highlight areas to improvein the future, then use a tool that evaluates the impact of changing your management. These tools tend to need more data added in at the start so that the impact can truly be seen.
Sequestration–in or out?
A key question 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 should not be overlooked. If the tool does not include sequestration, then the footprint will be looking at the negative without the positive!
Getting started
Once the decision has been made on which tool to use, the first step is to gather all of the input data. This includes information on fuel use, livestock numbers, fertiliser inputs, use of materials,waste produced etc. The list can look daunting at first, but if farm record keeping is reasonable then this process should be achievable in a couple of hours. It will be quicker next time!
It is then just a case of entering the data into the calculator, no more than an hour’s work, after which you should have a breakdown of carbon emissions by sector, both in amounts (kg or tonnes of CO2) and percentages of the total footprint by category. Armed with this data you are then ready to think about how to reduce emissions and increase sequestration.
When completing a carbon footprinting although value can be seen from completing it as a one-off exercise, the really interesting part comes when the process is repeated at regular intervals, usually annually. Then you can start to see the direction the farm is moving in and whether the actions you are taking are working.
Emissions sources
Although each farm will vary in its carbon footprint, the pie chart shows the average breakdown of emissions across a typical arable farm.
Data courtesy of: DEFRA. (2020) Agricultural Statistics and Climate Change. Tenth Edition and IPCC. (2014) Fifth Assessment Report (AR5)
Next steps
This is the interesting part! The results will be reflected as a carbon dioxide equivalent but should also show how that breaks down into the three greenhouse gases. Key areas to focus on are the management of soils, fertilisers, manures, livestock, cropping, energy and fuel. There are numerous opportunities to reduce emissions and costs as well, leading 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 foot printing is the first key step.
The spotlight is being well and truly shone at agriculture’s carbon credentials at the moment, and this offers an opportunity for us to take the first step and understand what is happening on our individual farm, and what we can do to improve profits, reduce emissions and build soil health and sequestration. Carbon offers a fresh lens through which to evaluate our business and build resilience for the future.
This article first appreared in NIAB Landmark, issue 42 May 2020, written by Becky Wilson, Farm Carbon Toolkit
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