The UN World Meteorological Organisation’s State of the Global Climate Report 2021, published on 18^th May, reinforces the urgency for Ireland to fulfil its commitment to ‘transition to a climate resilient, biodiversity rich, environmentally sustainable and climate neutral economy’ by 2050 – the ‘national climate objective’ described by the 2021 amendment of the 2015 climate Act.

To help achieve this objective, the Act mandated the Climate Change Advisory Council (CCAC) to provide for the establishment of set 5-year carbon budgets up to 2030 and a provisional budget for 2031-2035. These budgets act as statutory limits on Ireland’s total emissions and as interim milestones in climate action that must be aligned with equitably meeting the Paris Agreement temperature goal.

As a result, in October 2021 the CCAC set carbon budgets of 295 MtCO₂e for 2021-2025 and 200 MtCO₂e for 2026–2030, with a provisional budget of 151 MtCO₂e for 2031-2035. These approved budgets were adopted by the Oireachtas with effect from 6th April 2022.

Development of these budgets was based on Ireland’s 2018 annual total emissions of 68.3 MtCO₂e.  If emissions had stayed at that 2018 level for a 5-year period then 342 MtCO₂e would (hypothetically) be emitted. Relative to sustaining this 2018 level for 5-years, for the approved 2021-25 first carbon budget there is a 14% emissions reduction (47 MtCO₂e). And for 2026–2030 second carbon budget the reduction is 41% lower (or 142 MtCO₂e).

Budget deficits must be carried forward into the following period: so if the emissions budget in the first period is breached, the budget for the second period must then be reduced by that excess amount: that is, delay in the required level of emissions reduction only makes subsequent adjustment even more drastic (and expensive). This, unfortunately, is the blunt physical reality of the predicament created by our feeble and equivocal action to date.

Emissions ceilings, for all sectors, are due to be announced by Government shortly. Effectively, these will represent an allocation or divvying up of the national budgets among sectors within our society and economy. For the first time, they will set statutory limits on greenhouse gas emissions, on a sector-by-sector basis, for each of the 5-year periods.

However, an important question potentially arises if the original basis for the national budgets (referenced to the reported annual emissions in 2018), is retrospectively revised, due to changes in the technical emissions accounting approach for any particular sector’s emissions.

This possibility has already been explicitly raised in relation to the agriculture sector. A recent report in the Irish Independent (May 11^th, 2022), stated provisional results from Teagasc indicating that the methane “emissions factor”, the estimated average annual methane emissions from each dairy cow, is "probably overestimated". Dr Shalloo, Teagasc, said: "At the moment the models suggest a cow produces about 0.12t of methane per year, while our most recent methane measurements across a number of studies are suggesting that this figure is too high.”

This question having been raised, it is very important to emphasise that a change in sectoral emissions factors would be essentially a change in bookkeeping: it would not correspond to any actual physical reduction in emissions and therefore would not, in itself, represent a contribution to mitigation of climate change. The climate responds only to what we physically do; it is entirely unaffected by how we measure or report what we do.

For this reason it is important to be clear about what such a revision in an emission factor would - and would not - imply for the new emissions ceilings that will shortly be applicable to the agriculture sector and other sectors over coming years. Such a change in a sector-specific emission factor would not just change the reported emissions for one sector, but would also necessarily change the total reported national emissions by exactly the same amount.

The Climate Act does not prescribe a specific detailed mechanism for dealing with such an eventuality. However, the most direct response would be to require an exactly corresponding reduction in the overall national emissions budgets. In order to then reflect this formal reduction in the national budgets back into the sectoral emissions ceilings, for any sector where reported emissions are reduced, its sectoral emissions ceiling would simply be reduced by that same amount.

While there might be some further fine tuning around the details of such adjustments, the overall practical change on the ground would likely be minimal: the ongoing requirement for progressively more stringent measures to physically reduce actual emissions would be essentially unchanged.

Moreover, the Climate Act includes a requirement for “consistency” with the Paris Agreement, especially in equitably meeting the temperature goal. Given that several scientists have actively argued that the existing budgets are already higher than should be considered as prudently, equitably, consistent with the Paris Agreement, then any re-opening of the budgets would require that consistency to be reassessed and possibly that the budgets be further tightened.

Of course, the scientific basis for a material change in the methane emissions factor for dairy cows in Ireland has not even been established as yet. It is based on ongoing research that will have to be subjected to rigorous international peer review and validation through multiple independent assessments before it might prudently be incorporated into either our international reporting or our domestic budget process. This could take several years, whereas prompt climate mitigation is required by all sectors.

Therefore, there is a genuine moral hazard that public speculation about such a change, coupled with a naive view of how it might interact with the national emissions budgeting framework, could act to weaken or undermine immediate actions to physically reduce such emissions. This would potentially represent a pernicious "discourse of delay" for climate action.

We would hope that Teagasc and the Department of Agriculture would be alert to this risk, and will make a clear public statement to clarify that the ongoing research does not support any such delay; or, absent that, that the Climate Change Advisory Council will intervene to ensure that the agricultural community, and wider Irish society, is not misled about the scale and urgency of transformative climate action that is now required in all sectors.