Last month, climate was a key focus at the NFU Conference 2020, which included a session on ‘Climate change, the challenge of our time’. At the session, the NFU launched the ‘Net zero: Farm status indicator’, a new carbon footprinting tool, which offers a practical guide for reducing greenhouse gas emissions on farms.
The NFU has already shown real leadership in the farming industry, by declaring a goal for the sector to achieve net zero by 2040, a decade earlier than the UK government’s national target. But, what does net zero in agriculture actually mean, and can this be achieved by 2040?
What does net zero mean?
Net zero simply means achieving a balance between the quantity of carbon taken out of the atmosphere and the quantity emitted.
Growing plants, whether they’re crops, grass or trees removes carbon from the atmosphere, as carbon dioxide is absorbed and converted into sugars through photosynthesis. Sugars are then incorporated into plant matter, and will move through the food chain as animals eat them. All sorts of processes will release carbon, like respiration, carbon contained in faeces or burning of wood for fuel.
In a system that is achieving net zero there will be as many units of carbon absorbed from the atmosphere as there are emitted into it. This is irrespective of whether the system is totally natural or involves human technologies.
The use of fossil fuels at any scale makes it incredibly difficult to achieve net zero, as they release carbon that has been stored for thousands of years into the atmosphere which requires vast amounts of carbon capture to achieve a balance.
Can net zero be achieved in farming?
Farming contributes about one tenth of the UK’s greenhouse gas emissions. However, as a sector it is also well placed to help the country achieve net zero, as growing crops or grass captures carbon from the atmosphere.
Anaerobic digestion technology can be used to generate biogas from products that would otherwise be waste, like manure or crop residues. Biomethane produced by an on-farm AD plant can either be used as fuel on the farm, or injected into the national grid to heat homes and businesses across the country.
Feeding biomethane from agricultural waste into the national grid currently reduces the demand for fossil fuels, helping to decarbonise heating. Imagine how much more can be achieved, if agricultural wastes from every farm were to be processed through AD.
Broadley Energy, an on-farm AD plant near Chichester, is run predominantly on pig manure and straw, a by-product from cereals production. It supplies 1.8MW of green electricity to the national grid each hour.