Why I’m exploring dairy’s net zero trade offs – Nuffield Scholar Miles Middleton

In this blog post, Future Farmer and farm vet Miles Middleton from the Yorkshire Dales explains why he chose to study dairy’s net zero mission as part of his 2022 Nuffield Farming Scholarship, sponsored by the Yorkshire Agricultural Society. 

It was with great pride that I was recently named as a 2022 Nuffield scholar, studying my title “Working Towards Net Zero in the Dairy Sector; trade-offs, opportunity costs and alternative allocations for scarce resources”.

I would like to start by thanking my Nuffield sponsor, the Yorkshire Agricultural Society for giving me this fantastic opportunity.

I feel the topic is very wide ranging in scope, but unfortunately, shrouded in dogma and to a tangible degree, has become politically weaponised.

Nevertheless, there are inescapable truths. The global population is growing, currently very rapidly. There is a relatively finite amount of farmland.

Objectively and subjectively the climate appears to be changing and it appears likely that human actions have affected this process.

Emissions and key trade offs

Irrespective of our individual opinions or whether we like it or not, the political winds of our current time are already forcing all of us to consider the issue of emissions.

It is however, evident to all of us that this sits within a wider, more encompassing picture. Must this and should this come at the cost of production?

It’s obvious that if we as an industry and as a country produce nothing the road to ‘net zero’ will be greatly simplified.

The UK has a climate ideally suited to grassland farming and I fervently believe that UK grassland farming systems have the potential to be one of the most productive, efficient and resilient food production systems in the world.

A complicated picture

Clearly the ‘road to net zero’ is almost uniquely complex with respect to grassland farming.

There are myriad of different gasses and sources of emissions, coupled with what is a unique opportunity to sequester carbon through what is a core business function.

It is well documented within the scientific literature that globally, there is more carbon in the top one metre of topsoil, than in all the plants, all the trees, all the animals and in the entire atmosphere combined!

Through custodianship of the soil, small changes in soil carbon, multiplied up across the country or even the globe can sequester (or emit) huge quantities of carbon from the atmosphere.

Improved soil health will drive improvements in production, and resilience but at the apex end of this, what are the trade-offs to be made with production?

Can herbal lays be as productive, as palatable and facilitate animal performance as well as rye grass?

Do these trade-offs exist and under what situations are they worth it?

Measuring emissions

There remains contention even around how emissions are measured.

GWP100 (the conventional metric for quantifying emissions) assigns to one tonne of methane a ‘Global Warming Potential’ 28 times that of one tonne of carbon dioxide.

This system of quantifying emissions presents a significant challenge to grassland farming.

Using this score card, methane is estimated to make up over 45 per cent of emissions on the average dairy farm.

Fortunately, there is broadening public awareness around the nuances of methane emissions.

It is not well publicised that the Amazon rainforest emits 3.5 per cent of all global methane emissions. More than all the cattle in North America and Western Europe combined!

This occurs through exactly the same process of microbial breakdown of structural plant fibre.

Again, using the GWP100 score card these methane emissions make the amazon rainforest a significant net contributor to global emissions.

In 2019, however, total atmospheric methane was estimated to have risen by around 20 gigatonnes, with 110 gigatonnes of methane estimated to have been emitted alone through fossil fuel extraction and leaking pipes, so there are perhaps far more obvious solutions to tackling emissions than cutting down the rainforest!

Tackling inefficiencies is vital

For me, the industry must not transfix upon methane but look beyond.

Excluding methane the greatest contributors to emissions on dairy farms are, bought in feed, nitrogen fertilizer, nitrogen losses, and fuel.

Clearly these map particularly well to many of the main financial costs.

There remain significant inefficiencies within the industry, from management of nitrogen inputs to grazing strategies to livestock efficiencies and endemic disease.

Within each of these areas there is dramatic variation between farms. All of these losses drain money from the bottom line as well as driving the ‘carbon cost’ of food production.

The challenge for the industry is quite simple, produce more using less of everything while enhancing soil quality and biodiversity.

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