Farming carbon auditing scheme is still a work in progress - Brian Henderson

Carbon – the root of the name stems from the Latin word for coal. It is a tetra-valent, non-metallic element which, while nowhere near the most abundant, accounts for more compounds than all other elements combined.

Agricultural carbon auditing is imprecise

From the broader farming perspective, despite the fact that it is one of the elements common to all life forms, until only a few years ago there would be little or no mention of it in the industry, in the press or even in scientific journals.

But, fast forward to today and you can’t escape the word – with endless talk of how to mitigate its emissions, how to sequester it, how to audit it and even how to trade the blessed stuff.

And today sees the starting gun fired on a national effort to encourage the sector as a whole to get to grips with the issue as the first phase of the Scottish Government’s Track 1 of their new sustainable farming policy opens for business.

In truth when the term carbon is used, rather than referring to its elemental forms – such as diamond, graphite, coal and coke - it is simply used a shorthand for one key molecule - Carbon dioxide, the combination of one carbon atom and two of oxygen.

Under the Intergovernmental Panel on Climate Change (IPCC) rules, which focuses on the greenhouse gas potential of different chemicals, CO2 is taken as the standard unit of warming pot effect, with other gases being given a ‘CO2 equivalent’ value.

And while other sectors of industry have been swift to see the marketing advantages of being able to claim they are carbon neutral or negative, this exercise is asking farmers to audit their businesses and assess how much they release and how much they tie down during their operations.

For most types of industry this might be a fairly straightforward calculation – with transport, power and other energy sources which are consumed in the production, packaging and delivery of their manufactured goods being totted up to give a carbon footprint.

Farming, on the other hand is slightly more complicated.

For farming harnesses natural processes – which tend to be more messy and more difficult to quantify or accurately predict.

And, along with forestry, farming has the unique ability to actually absorb CO2 and reduce the amount which contributes to the global warming potential of the atmosphere.

Every blade of grass, every head of corn, every grain of barley has the ability to lock up CO2 through the primary driving force of life on Earth – photosynthesis. And that’s what farming is ultimately about – harvesting solar energy from the sun and turning it into food for the human population.

But, and this is a very big but, while the accepted international protocol for calculating emissions is pretty much understood and standardised, that for allocating credits for the sequestration is less well developed.

And while the convention has taken the decision to recognise the amounts of CO2 absorbed by forestry and woodlands as being fixed there (despite the fact that much of this is returned to the atmosphere through burning in woodchip boilers and suchlike) what is fixed by grain and other crops which are consumed fairly swiftly do not receive the same recognition.

So despite the fact that every acre of barley actually locks up several tonnes of CO2, rather unfairly in my opinion, no credit is given for this due to the fact that it will soon be consumed.

The issue is further complicated by the use of fertilisers to boost productivity, the addition of grazing livestock to turn grass which is indigestible by humans into readily digestible animal protein – and this practice is yet further complicate by the emissions of methane by the bugs inhabiting the stomachs of the ruminants which we use to do this.

So far it has proved difficult for the amount of CO2 sequestered in grasslands to be calculated, and also that added to the soils through the absorption of crop residues – and while the science is developing it is yet to be perfected.

Currently the different processes used in the multitude of carbon calculators (or perhaps more accurately ready reckoners) for undertaking the results can give hugely varying results for individual farms.

So while the Scottish Government’s new carbon auditing scheme may mark a starting point for benchmark the industry’s performance – until the science is better understood, more fairly recognised and fully integrated into a single, standardised calculator it should be viewed as work in progress rather than as a final result.