Farming and the climate debate

With the popular press and mainstream media pointing fingers at agriculture for greenhouse gas emissions, and at milk and meat production and consumption in particular, it is easy for farmers to feel ‘got at’ when it comes to the climate change debate.

Add in the fact that there are around 50 different farm carbon accounting tools available, all giving different answers to the question ‘what is my farm’s carbon footprint?’ and it’s easy to see how confusion can reign for farmers trying to produce heathy food in a responsible way and struggling to make a profit from doing so. An explanation of the numbers helps demonstrate how to focus on the main issues, and – with the aid of Kelvin Cave’s approaches to forage production and management – can help producers make some progress.

Farming carbon emissions – the latest

The most recent numbers available from The Department of Energy Security and Net Zero are for 2021 and were published in March 2023. They show emissions from agriculture were 49.2 million tonnes (Mt) for the year, 11.5% of the UK total of 426.5 Mt. Enteric methane emissions (from rumination) from all of the cattle in the UK (the infamous belching cows highlighted by the mainstream media) were 18.1Mt – that’s 36.8% of agricultural emissions and just 4.2% of the UK total.

With industry use of gas and electricity at 17% of total UK emissions, passenger car use at 15% and residential use of gas and electricity at 23%, we can see why it feels unfair for there to be such a focus on cattle that are producing milk and meat foods. If it helps, cattle farming is not the only sector to have an inappropriate level of public scrutiny – the aviation industry also seems under the cosh at the moment, and in 2021 all domestic and international flights accounted for a whopping 0.5% of UK greenhouse gas emissions!

The reality is that our Government is signed up to various protocol and targets to reduce greenhouse gas emissions, and every sector (agriculture, transport, business, public sector, industry, residential, waste management) is expected to take action to reduce emissions.

So, like it or not – unfair or not – overblown or not, we are on a ‘net zero journey’ and that means measuring where we are and planning to make reductions.

In case anyone is wondering, ‘net zero’ simply means a position where all the greenhouse gases we emit are balanced by all the greenhouse gases that we capture.

Greenhouse gases – what they are and how they lead to climate change

The greenhouse gas effect is a natural phenomenon. It’s how the climate of the earth exists so that we can have life on the planet. Energy from the sun warms the earth’s surface and this energy comes in a variety of wavelengths. Energy in the infra-red wavelength hits the earth, warms it and is then released up into the atmosphere, where some escapes back into space and some is absorbed by greenhouse gases. These gases then release the infra-red radiation back to the earth, where it again warms the surface. This is the same process by which greenhouses are warmer than the air outside (the glass traps some of the energy and chucks it back into the greenhouse). Hence the name.

So, we need greenhouse gases in the atmosphere to keep the earth warm, otherwise we’d all be living in arctic conditions (or more likely, not living at all). But the more greenhouse gases there are in the atmosphere, the more infra-red radiation is trapped and released back to the earth, and the more global warming we have. If we want to keep the earth from warming too much (the widely quoted safe limit of 1.5oC), then we need to pump less greenhouse gas into the atmosphere.

The three main greenhouse gases are carbon dioxide, methane and nitrous oxide. The table below shows their greenhouse gas potential and how long they last in the atmosphere.

These three gases trap infra-red radiation at different rates and this is why they are distilled down to ‘carbon dioxide equivalence’. So, releasing 1kg of methane has the same warming effect as 25kg of carbon dioxide, and 1kg nitrous oxide is the same as 298kg carbon dioxide.

All three gases are emitted by agricultural practice and operations, so your farm carbon footprint makes a calculation of the three gases emitted, based on what and how you farm, and expresses them as a carbon dioxide equivalent (CO2e). The accounting tools use different models to predict the emissions of these gases, based on how you farm (amount of forage produced, fertiliser applications, concentrates fed, tractors driven, electricity used, etc), so they all come up with different overall numbers for the same farm.

So, the practical lesson here is, choose the carbon footprinting tool that best suits your farm and stick with it. Your milk or meat buyer might insist on the use of a certain tool anyway, so for many of us, this decision is taken out of our hands.

For agriculture, around 13% of emissions come from carbon dioxide, 33% from nitrous oxide and 54% from methane. The table below gives some indicators of the operations that release these gases.

Areas to focus on

There are a lot of ‘first three things to consider’, and ‘top five tips’ out there when it comes to reducing greenhouse gas emissions. The good news for cattle farmers is that most of the reduction measures are associated with increasing the efficiency, and therefore potential profitability, of milk and meat production.

It is interesting to look at what the supply chain are focused on for their primary food producing farmers. An example worthy of exploration comes from Arla, who facilitate the carbon footprinting of around 2,000 of their dairy farmers in the UK every year. Their analysis shows a carbon use of 1.1kg CO2e per kg milk, which compares with the UK average of 1.25 and the global average of around 2.5kg CO2e per kg milk.

Arla has five priority areas for carbon reduction, and what Kelvin Cave Ltd does fits directly into four of these:

1. Feed efficiency – reducing the kg dry matter fed per kg milk. Making and preserving the highest quality of home-grown feed and forage reduces brought-in feeds, which mostly have more cost in terms of both cash and carbon. A kilogram (dry matter) of dairy parlour concentrate typically costs at least twice as much to feed as a kilogram DM of home-grown preserved forage and at a carbon accounting cost of around 1kg CO2e per kg concentrate. Making the most of home-grown energy and protein has been the focus of the Kelvin Cave business for over 40 years, so if you follow the company’s approach and choose your options wisely, you’ll make progress on this score.

2. Protein efficiency – ruminants are inefficient users of nitrogen, which is the main constituent of proteins. Raising nitrogen use efficiency, even by a small amount, say from 20-25% per animal, will reduce the amount of surplus protein in the farming system and cut losses from nitrous oxide. Kelvin Cave Ltd is part of a national research consortium looking at developing systems for producing more high quality home-grown protein using peas and beans, so watch this space over the next four years for ideas, approaches and support.

3. Reducing mortality – lower replacement rates mean fewer rumens on-farm and fewer rumens mean lowered enteric methane emissions.

4. Reducing the use of manufactured nitrogen fertilisers -The carbon cost of bringing manufactured nitrogen on farm and the nitrous oxide emissions from their application can represent 10-20% of a cattle production system’s carbon footprint. So, anything that can be done to reduce the need for nitrogen fertilisers will help with the pocket and with carbon. Credible, evidence-based slurry additives like Digest-It from the Kelvin Cave stable, can improve the availability of nitrogen in slurries and thereby cut the use of nitrogen fertilisers by 20-30kg N/ha. That represents a 4:1 return on investing in using the product and a reduction of
130-195kg CO2e per ha.

5. Improved crop yields – Arla express crop yield as the m2 it takes to produce a kg of milk. The approach is, the more crop yield you have, the more milk you can produce from your land and therefore you get more milk for the carbon you use. In other words, it’s a different measure of efficiency. What we tend to forget here is that it’s not just about crop yield when it comes to making grass and maize silage or crimped grain. It is also crucial to preserve that quantity and quality without losing dry matter from the clamp during ensiling and feedout. This is where the Kelvin Cave approach helps again – the company is all about providing you with the products that give you the best of both worlds when feeding your preserved feeds, which means focusing on preserving the amount and quality of what you have harvested right to the animal’s mouth.

To sum it up, the carbon reduction, net zero journey is not going away. Your main customer is under pressure to show what they are doing about it, as well as the rest of the supply chain, from your farmgate to the consumer’s dinner table. The opportunity is that most of the reduction measures at the farm level also improve efficiency and therefore potential profitability. The good news is that Kelvin Cave has important solutions for your farm and is at the forefront of developing improved approaches for the future.