Greenhouse gas or carbon emissions from the dairy sector contribute about 33% to all livestock farming emissions in Ireland.

Almost all activities in life, whether inside or outside the farm gate, have a carbon footprint. In dairying, the main contributor to carbon footprint is methane, which is responsible about two-thirds of all dairy emissions.

Methane is a greenhouse gas that can come from a variety of sources such as fracking, mining, landfill and from ruminant animals when microbes digest feed in the rumen. About 85% of all methane emissions on dairy farms comes directly from the cow’s rumen, with the other 15% coming from methane emissions from slurry storage and spreading.

Because methane emissions are directly linked to livestock, there is a huge emphasis on livestock numbers in the debate on carbon emissions from agriculture.

Urea-based nitrogen has much lower nitrous oxide emissions and this is why urea or protected urea is the preferred nitrogen source

Strategies such as encouraging farmers to slaughter animals earlier or breed more fertile cows that require fewer replacements per annum all contribute to reducing methane emissions, because there are fewer animals in the system while not actually affecting cow numbers or milk output.

About 15% of emissions on dairy farms come from fertiliser use, mainly CAN-based fertilisers, as these release nitrous oxide gas, which is a potent greenhouse gas.

Urea-based nitrogen has much lower nitrous oxide emissions and this is why urea or protected urea is the preferred nitrogen source, as it has a much lower carbon footprint compared to CAN.

The carbon emissions associated with feed and silage production make up about 14% of total dairy emissions, while energy, fuel and other emissions make up a further 6% of greenhouse gas emissions on dairy farms.

Making the cuts

Achieving a 25% cut in emissions from agriculture means that the new ceiling for agricultural emissions is 17.25Mt in 2030. This represents a reduction on the 2021 emissions level of 5.847Mt of CO2.

Up to now, the debate around emissions has centred on how farmers can reduce emissions before they need to start reducing actual cow numbers.

The Teagasc figures show that if all farmers in Ireland implemented what is contained within the Teagasc marginal abatement cost curve (MACC) curve, that 1.85Mt of CO2 would be saved per annum. The main steps contained in the MACC include:

  • Improving EBI.
  • Extending the grazing season.
  • Incorporating clover to reduce fertiliser use.
  • Switching away from CAN to protected urea.
  • If every farmer in the country took these practices on board, it would achieve 32% of the total cut to greenhouse gas emissions required by 2030. It’s important to note that there would be a financial benefit to farmers undertaking these measures on top of the benefit of reducing greenhouse gas emissions, so really these are no-brainers for all Irish farmers.

    However, the financial benefit of these measures were present long before anyone mentioned greenhouse gas emissions and yet uptake among farmers was poor.

    So it would be incorrect to assume that just because these measures make sense, they will be implemented.

    In the event that they are all implemented, it still leaves a shortfall of 4Mt of CO2 to be cut. An exact plan for removing this carbon has yet to be worked out.

    The roadmap towards 17.25Mt of total emissions by 2030 highlights the possibilities that exist regarding feed additives, genetics, early slaughter and changes to fertiliser use. Some of these are dubbed “almost-ready technologies” and should deliver savings of between 1Mt and 1.5Mt of CO2.

    Early-stage technologies such as feed additives at pasture and breeding low-methane-emitting animals are a bit away yet from being ready to implement. Whether or not they will come in time to make a substantial impact on emissions before 2030 remains to be seen.

    Not only would this reduce methane emissions, which make up two-thirds of all emissions from agriculture, but it would also reduce all other emissions

    According to the Teagasc roadmap, it is expected that these technologies could remove between 1.5Mt and 3Mt of CO2 per annum.

    One thing is for sure – in order for agriculture to meet its target of removing 5.847Mt of CO2 by 2030, the MACC curve and both the almost-ready and early-stage technologies will have to be implemented in full. The fact that we don’t yet fully know what these technologies are, how they will be implemented, how much they will cost and who will pay for them just highlights the enormity of the challenge ahead.

    Of course, the challenge would be significantly easier if the size of the dairy and beef herds was reduced. Not only would this reduce methane emissions, which make up two-thirds of all emissions from agriculture, but it would also reduce all other emissions, as less fertiliser and less feed would be required.

    At an average herd size of 100 cows per farm, this would equate to over 2,200 dairy farmers changing system

    While Teagasc, the Department of Agriculture and most politicians have denied that such a move is necessary, environmental organisations and Green Party politicians have not been as shy in calling for a reduction in the size of the national herd to comply with the climate change commitments.

    The fact that the Food Vision Dairy Group is openly discussing plans to compensate farmers for reducing their herd size is a clue as to the future policy direction.

    As reported by the Irish Farmers Journal last week, the group chaired by Gerry Boyle was told that culling 10,000 cows would reduce CO2 emissions by 45,000t. Therefore, to reduce CO2 emissions by 1Mt, dairy cow numbers would have to fall by 222,222 cows.

    At an average herd size of 100 cows per farm, this would equate to over 2,200 dairy farmers changing system.

    If the proposal to pay €5,000 for every cow culled was followed through on, it would cost over €1.1bn to compensate farmers for the loss of their dairy cows.

    The introduction of a new cow quota now seems inevitable

    The true cost to the Exchequer and rural economies would be much greater, with less milk being processed, less inputs being purchased and less rural employment.

    Furthermore, farmers who quit dairying will have to find alternative income sources and will likely have to commit to never again milking cows or keeping ruminant breeding stock.

    The introduction of a new cow quota now seems inevitable. This will be used to curtail growth in overall livestock numbers and will also form the basis of a mechanism to trade quota between farmers.

    The net result of this will be that existing livestock farmers have a new asset, while new entrants and those looking to expand their operations have a new hurdle to jump.