This report quantifies current emissions associated with UK livestock food production and assesses technologies that can put this industry on an immediate trajectory to deliver a key component of the net zero carbon goals for UK agriculture and the UK as a whole.
The UK farmgate value of livestock products is over £12 billion per year. We import £10 billion and export £4 billion worth of livestock products each year – which makes the UK broadly 60 – 70% self-sufficient, on a calorific basis, for meat, milk and eggs. The livestock industry is vitally important to the economy and provides society with an essential source of high-quality protein and other micro-nutrients. It also manages our landscapes and supports rural communities.
Food production is part of a cycle whereby energy from the sun and carbon dioxide from the air are converted into plant nutrients. Some of these are incorporated into soils, while others are eaten by animals which upgrade them to high-quality protein for human diets. Animals produce carbon dioxide and ruminant animals produce methane, both of which are greenhouse gases. Whilst methane is cycled in the atmosphere, some of which is converted to carbon dioxide, the presence of methane in the atmosphere significantly impacts global warming.
Since no biological processes are 100% efficient, we cannot expect to maintain an efficient food production system without emissions. However, we must work to eliminate, as far as possible, net losses of carbon into the atmosphere, and to reduce the levels of greenhouse gases emitted to decelerate and eventually halt global warming. Livestock agriculture can make a contribution to achieving this.
The Committee on Climate Change has recommended a 64% reduction in greenhouse gas emissions from the agriculture and land-use sector to meet a 2050 net zero carbon target in the UK. Whilst livestock does not have a specific target, it is considered that the same target is appropriate. The fact that this is not a 100% reduction reflects the natural biology of food production, as well as the importance of food security to the UK.
A 64% reduction from 2018 baseline livestock emissions (total 29.1Mt CO2-eq) is 18.6Mt CO2-eq. Over the 32 years between 2018 to 2050, this is a reduction rate of 0.58Mt CO2-eq/year. To achieve this will require application of a range of mitigation and carbon removal strategies. For all agricultural emissions, a recent assessment of cost-effective mitigation strategies available concluded there is the potential to reduce emissions by 7.1Mt CO2-eq by 2035. This is only 19% of the goal for total agricultural emissions, leaving 81% to be delivered between 2035 and 2050.
In the most recent national inventory assessment of the UK’s emissions, agriculture was responsible for 10% in 2018 (45.4Mt CO2-eq), with nitrous oxide and methane emissions accounting for 31% and 56% of this respectively. Most methane emissions (87%) originate from ruminants as part of their natural digestive process, so almost half (49%) of all agricultural emissions come from ruminant livestock 1. Other emissions come from nitrous oxide, produced from the application of nitrogen fertilisers and livestock manures, and from the production of imported feedstuffs, such as soya (which if associated with land use change, such as deforestation, can be very significant).
Ruminant farming is considered a major source of greenhouse gas emissions in UK agriculture, but changes effected here can reduce UK emissions significantly.
Much of the focus for livestock is around reducing emissions at source, on-farm. However, maximising carbon capture will also be important in soils, hedgerows and woods. Off-farm emission load can also be reduced through sourcing of inputs that have low carbon footprints themselves, such as green energy or locally produced inputs (such as fertiliser and feed).
An important part of working towards net zero includes the accurate accounting of greenhouse gases. However, this is complicated within agriculture. There are two accounting systems in common use to assess carbon footprints, each with different assumptions. Our net zero carbon targets are based on inventory accounting, which relates only to emissions originating in the UK. This method of accounting forms the basis of international climate change treaties. Another method, life cycle assessment, includes emissions occurring in other countries for imported products associated with food production, such as animal feed (e.g. soya imported from the Americas), or fertiliser chemicals. As such, it provides a more globally holistic view of the carbon footprint for any product. However, because of the interconnected natural world, life cycle assessments must make assumptions about system boundaries, and these can vary considerably from assessment to assessment. So, careful consideration of accounting method and assumptions made is needed to avoid misinterpretation of data and unintended consequences. For instance, we can lower the UK inventory carbon footprint by replacing home grown feedstuffs with imported equivalents, but this will negatively impact global emissions if those imports have a higher footprint overall.
This report has identified the following eight areas of opportunity (Improved efficiency, Novel and alternative feeds, Addressing nitrogen fertiliser use, Smart technology and precision livestock farming, Carbon sequestration and accounting, Whole system understanding, Enhanced calculation methods, Improved reporting of emissions and uncertainties) to advance the livestock industry towards net zero carbon at pace and with efficacy. To maximise speed of uptake and rate of change, most require coordinated and collaborative work within and across sectors, between farmers, food processors and their supply chain partners, and partnerships between government, scientists and consumers.