One of the challenges in both measuring and improving farm sustainability is that every farm is unique.
Farms differ in term of size, in terms of what they produce and in their production intensity. These factors all influence the level of emissions of greenhouse gases or ammonia from individual farms.
Therefore, while reporting the total emissions from individual farms is relevant, greater granularity, focusing on emissions per hectare or emissions per unit of product provides a more relevant farm assessment.
GHGs emitted by dairy, cattle, sheep and tillage farms can be converted to a common currency of CO2 equivalents, which allow comparisons to be drawn across these farm types.
A three-year rolling average is used to iron out the impact that variable production conditions or positive and negative price shocks can have on emissions from one year to the next.
This three year averaging approach is more likely to identify a trend through time. Figure 1 shows total farm level emissions per hectare on a three-year rolling average basis (e.g. 2010-2012, is the average of the years (2010, 2011 and 2012).
Due to the more intensive nature of production, GHGs emissions per hectare from the average dairy farm are over twice the level found on the average drystock farm and nearly four times those on the average tillage farm. Emissions on non-dairy farms have tended to remain static over the period examined, whereas emissions on dairy farms have trended upwards, reflecting the growth that has happened with milk quota removal.
However, when GHG emissions are expressed relative to the revenue generation capacity of the farm (layering environment and economic sustainability together) the story changes, as seen in Figure 2.
Due to their superior revenue generating capacity and consequent economic sustainability, on average over the period examined dairy farms produce close to half of the GHG emission per euro of output compared to cattle farms. Similarly dairy farms generate only about two thirds of the emissions per euro of output compared to sheep farms.
However, as noted in the report, on the basis of kg of product produced (milk, live-weight beef and sheep) the carbon footprint of production has been declining over the study period across all farm types.
The fact that ammonia emissions in Ireland come almost exclusively from agriculture means that any future national ammonia reduction target for Ireland would de facto have to be achieved by the agriculture sector.
As with GHG emissions, dairy farms have the highest level of ammonia emissions on a per hectare basis.
Dairy farm ammonia emissions are on average 2, 3.5 and 5 times higher than cattle, sheep and tillage farms respectively.
Non-dairy farm ammonia emissions have again remained relative static on a per hectare basis over the study period. However, ammonia emissions on dairy farms have been trending upwards since EU milk quota abolition.
When ammonia emissions are expressed relative to the associate revenue generated on farms (layering environment with economic sustainability together) a somewhat different picture emerges.
Cattle farms are the highest emitters of NH3 per euro of gross output generated, 1.8 times higher than dairy and sheep farms and four times higher than tillage farms. However, it again should be noted than on a kg of product produced (milk, live-weight beef and sheep) the ammonia footprint of production has been declining over the study period.
The sustainability report is a yardstick for the farm sector. It illustrates that there may be trade-offs in addressing all of the dimensions of sustainability, with gains in one area potentially meaning less progress elsewhere.
The sustainability report illustrates the incremental improvement in GHG and ammonia emission intensity in recent years.
However, the sector needs a step change in terms of its capacity to improve emissions intensity that would truly decouple emissions from production growth. Teagasc has produced marginal abatement cost curves that identify the scale and cost of actions that can further improve emissions efficiency in the years to come.
Research at Teagasc will continue in order to find additional tools that can be added to the arsenal of gaseous emissions reductions measures already identified, as well as solutions in other areas such as water quality and biodiversity.
Cathal Buckley and Trevor Donnellan are based at Teagasc, Mellows Campus, Athenry, Co Galway