The adoption of measures to reduce greenhouse gas (GHG) emissions needs to be “ramped up very quickly” in order to reach the 2030 target, Teagasc research officer, Prof. Gary Lanigan has said.
A new Marginal Abatement Cost Curve (MACC) identifying cost-effective measures to cut GHG emissions and enhance carbon sequestration has been launched today (Wednesday, July 12).
In a “business as usual” scenario, agricultural GHG emissions could drop to 17.0 million tonnes of carbon dioxide equivalent (MT CO2e) compared to 21.9MT CO2e without any abatement.
This scenario, which is the “most likely base case”, predicts dairy cow numbers to grow by 8% and a 29% reduction in suckler cow numbers over the period to 2030 and relative to 2022.
However, this level of emissions reduction assumes more ambitious adoption rates of identified mitigation measures and represents the maximum technically feasible adoption rate.
Emissions reduction target
Ireland has committed to a 51% economy-wide GHG emissions reduction target by 2030 based on 2018 levels. As part of this, the agriculture sector must cut its emissions by 25% by 2030.
In the base case with “very high levels” of adoption, Lanigan said the 25% reduction target, i.e. the emissions ceiling at 17.25MT CO2e by 2030 can be met by the “skinnier teeth”.
The measures identified in the MACC include:
- A three-month reduction in finishing age of cattle across the herd;
- Replacing 90% of calcium ammonium nitrate (CAN) fertiliser and 100% of straight urea with protected urea;
- The use of feed additives to reduce enteric methane in half of dairy cows;
- The uptake of diversification options to displace 140,000 livestock units.
Speaking to Agriland, he said that during the current carbon budget (2021-2025) the focus should be on cutting nitrogen usage, before tackling methane emissions in the second carbon budget (2026-2030).
“When we produced the 2018 MACC, I remember saying the exact same thing – we need to start adopting very soon. It is now five years later and we have six and a half years to go.
“We need to ramp up adoption very, very soon, particularly in the short term, go aggressively at reducing nitrogen. Then in the longer term, towards the end of the decade, go hard on methane.
“We have had very good uptake in Low Emissions Slurry Spreading (LESS) which has shown some improvements on our ammonia emissions,” Lanigan said adding that there has also been a reasonable uptake of protected urea.
Stressing the importance of advisors to “translate” the MACC into sustainable production systems, he said that not every farmer is going to be able to adopt all of the measures.
Teagasc highlighted that increased advisory and extension services will be “key” to helping guide farmers and landowners on the path to reduced GHG emissions by 2030 and towards climate neutrality.
MACC
Farmers and policymakers should first focus on nitrous oxide (N2O) mitigation, including the management of and reductions in the use of nitrogen (N) fertilisers, Teagasc said.
This can be achieved through a combination of reduced N fertiliser application and altered fertiliser formulation, either protected urea or ammonium-based compound fertilisers.
Key technologies to achieve this include greater use of white and red clover, optimum soil pH and soil phosphorus (P) and potassium (K) status together with enhanced use of legumes and multi-species swards (MSS), and the use of LESS.
In terms of methane mitigation, the MACC reflects the potential of reducing age at finishing by three months, the dairy economic breeding index (EBI), and feed additives that inhibit methane production in the rumen.
Manure management, in terms of slurry additives and aeration but also biomethane and extended grazing, could also reduce manure methane emissions, Teagasc said.
Diversification into organic farming, increased tillage and forestry or biomethane feedstock production has the potential to aid in herd stabilisation and contribute to meeting targets, the report states.
The potential for GHG abatement and the associated costs/benefits will change over time as ongoing research delivers new mitigation measures, or as socio-economic conditions evolve.