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CMP September 2021 Update – Choosing a Carbon Footprint Toolkit

Choosing a Carbon Foot Printing Toolkit
‘All models are wrong, but some are useful’.

22nd September 2021

You will likely be considering or have already calculated your business’s carbon footprint in a bid to identify and reduce your Greenhouse Gas (GHG) emissions with the aim of achieving the UK’s goal of Net Zero by 2050. The NFU set out how they wish to achieve farmland carbon storage in soils and vegetation at the following link . There are challenging aspects of quantifying GHG emissions from agriculture, but a good start is to complete a carbon/GHG audit.

This is a quick statement to say choosing the right carbon/GHG toolkit is important when trying to highlight where emissions occur on your farm to identify mitigation options enabling future reductions. A toolkit needs to be robust and credible enough for supply chain assessments; each calculator will use its own underlying principles, methodologies and assumptions. For example, each arable toolkit will use different assumptions based on soils, crop establishment, machinery, pesticide use, N fertiliser manufacturing emissions and applications. All the while, others can miss the mark and leave out factors such as emissions from soil, N fertiliser manufacture and land use changes (LUC) – i.e. grassland conversion to arable or vice versa. The average farm GHG emission result from different toolkits ranged from 606 to 3298 kg CO2 eq./ha so it would appear pertinent to choose your toolkit wisely (Whittaker et al., 2012).

Based on this recent paper, Cool Farm Tool scored highly for both being user friendly and providing a comprehensive account of GHG emissions occurring on a farm. Cool Farm Tool accounts for multiple factors such as LUC over the past 20 years which will have significant impact on your business’s score, soil nitrous oxide (N2O) emissions, emissions from fertiliser manufacturing and most importantly for farms aiming to reduce fixed and variable costs it allowed user defined parameters for LUC, tillage, inputs and residue management. Carbon sequestration is perhaps not a strong point within the toolkit. Uses accepted figures from the Intergovernmental Panel on Climate Change (IPCC)

A newer toolkit on the scene is Agrecalc – developed by SRUC & the SAC, it focuses on arable, livestock, machinery and energy emissions; aiming to report on carbon dioxide, methane and nitrous oxide. It also has an upcoming soil carbon module which will soon be made available for general use. This allows farmers to indicate tillage methods which in turn impacts soil carbon sequestration estimates. This will allow growers to differentiate between plough, min and no-till systems. Uses accepted IPCC figures.

Farm Carbon Calculator is a user-friendly toolkit, however, in my opinion it does not take into account all the factors needed to make a comprehensive emissions and sequestration report but can be a good starting point.

As you can see from the figure below, a general insight to an average arable enterprise will see the largest emissions arising from synthetic fertiliser use (nitrous oxide emissions) and/or LUC (grass/woodland to arable).

There remain many unanswered questions on emissions, land use and carbon sequestration – however, these toolkits all have free to use versions and the results of which may soon be required by legislation or land management schemes.


Tristan Gibbs
Crop Management Partners