New projected Land Use emissions take up a greater and increasing fraction of the carbon budgets

posted 3 Jun 2022, 09:29 by Paul Price

Key Points:

  • Due to updated science projected land use (LULUCF) net emissions to 2020 are now 3–5 MtCO2/yr higher under existing measures than was forecast in earlier Projections, and far higher than provided for in the core scenarios outlined by the Climate Change Advisory Council (CCAC).
  • Given the two agreed national 5-year carbon budgets for 2021–2025 (295 MtCO2e) and 2026–2030 (200 MtCO2e), and the provisional budget for 2031–2035 (151 MtCO2e), the projected LULUCF emissions take up a greater amount for each year and an increasing fraction over time of the total budgets compared to what had been suggested by the 2021 Projections and even greater fraction compared to the CCAC's small provision for LULUCF assumed in modelling for energy and agriculture. 
  • Therefore, if Ireland's agreed carbon budgets are to be met then far more policy attention is required in a revised Climate Action Plan to limit near-term emissions from Land Use. In particular, this implies that effective limits on forest harvest and peat extraction up to 2030 are likely to be needed (in addition to environmentally sensitive afforestation), as well as increased achievement in Energy, Industry and Agriculture sectors (for which projections show insufficient mitigation achievement).
  • In the Government's definition of sectoral ceilings by the beginning of July this year, realistic "sectoral ceiling" values for the five-year carbon budget periods need to be set for LULUCF net emissions (given these updated projections), otherwise the sectoral ceilings for other sectors will not be meaningful.

Charting the projected Land Use emissions pathways and 5-year totals relative to carbon budgets

As discussed in the previous post, the new EPA 2022 GHG Projections show substantially increased LULUCF net total emissions. This is particularly due to a revision of the forestry emission factors for plantation forestry on organic (peat) soils. In this post, having obtained the full data for the 2022 Projections, further detail is presented here for the new projected pathways for LULUCF and the resultant fraction of the 5-year national carbon budgets set out up to 2035. In the charts below, these new LULUCF projections are compared to the 2021 Projections and to the provision for LULUCF given in the October 2021 CCAC Technical Report [pdf] analysis (CCAC-TR).

Full details of Ireland's projected GHG emissions with mass data by gas and for CO2e are contained in an Excel file submitted to the EU by the EPA (a copy of the submitted Excel workbook ishere). 

The line chart below shows the 2022 projected net LULUCF emission pathways for the WEM (orange) and WAM (blue) scenarios. Also shown are the much lower emissions in the 2021 projections (grey dashed line) and much lower still in the CCAC-TR provision for LULUCF. For WEM, LULUCF emissions steadily increase from 7 MtCO2e in 2020 up to 13 MtCO2e in 2037.  For WAM, LULUCF emissions steadily increase from 7 MtCO2e in 2020 up to nearly 10 MtCO2e in 2037. For the revised WAM the "carbon cliff" from forest harvest is not so apparent as in the WEM scenarios, but the 2022 WAM pathway is nonetheless higher than the 2021 Projection's WEM=WAM pathway.

Ireland GHG emissions LULUCF 2022 projections pathways

The bar charts below give the five-year totals for LULUCF WEM (orange) and WAM (blue) emissions in the 2022 Projections, compared to the CCAC-TR provision (green) and the 2021 Projections (grey)  The upper chart is in MtCO2e for each of the five year budget periods to 2035. The corresponding lower chart shows the percentage of the overall national budgets taken up by the projected emissions in each case. This analysis indicates worryingly high LULUCF shares of the carbon budgets unless an emergency course correction in land management regulation is undertaken in the very near-term.

The CCAC-TR pathways assumed for LULUCF were clearly understood in that report to be very ambitious (even more so for the unrealistic 51% reduction by 2030), as only slow and delayed improvement in reducing net LULUCF emissions was anticipated due to the "carbon cliff" reduction in forest sink due to projected forest harvest and the delayed impact on net emissions from increased afforestation and organic soil rewetting. Unfortunately, the 2022 projections indicate that LULUCF emissions are likely to be far higher than previously thought, seriously increasing the LULUCF impact on carbon budgets.
In the three successive carbon budgets the CCAC-TR analysis for scenarios provided for LULUCF to take up 8%, 6%, and 6%, of the budgets, respectively. By comparison: the new WEM projected LULUCF takes up 15%, 27%, and 41%; and the WAM LULUCF takes up 13%, 21%, and 31%. This analysis indicates that far greater ambition and more effective implementation is required for LULUCF and for Energy, Industry and Agriculture, if there is to be a good faith societal commitment to meeting the carbon budgets.

New policies and measures to change these LULUCF pathways will require radical and rapid changes in management of all organic soil areas with forest, wetland and grassland, likely especially by limiting timber harvest, ending as much peat extraction as possible, and undertaking rapid rewetting of grassland organic soils. Certainly, any support for projects for drainage of organic soils needs to end.


As noted in the previous post, these new Projections suggest that a major revision of the Climate Action Plan is now required this year. New policies and measures in land use management, and across all other sectors (for which the projections show insufficient mitigation achievement), need to be undertaken as immediately as possible. It will be important that the public and media are made aware of the urgency of these early course corrections given Ireland's international commitment in the achieving climate action equitably aligned with meeting the Paris Agreement temperature goal.

Without prompt corrective action choices to meet the carbon budgets will become increasingly limited and more costly. As recent political and media focus on "turf wars" has exemplified, none of these options may appear palatable now, but, as the research on climate risk makes very clear, taking difficult decisions earlier rather than later lowers costs and keeps larger set of future policy options open. 

At this point, already a quarter of the way through the first carbon budget period, the urgency required to achieve the carbon budgets and all of the constituent sectoral ceilings cannot be overemphasised. Far greater public and media awareness of this reality could enable increased political will to overcome inaction and drive necessary action. 

How might changes in sectoral emissions factors and totals affect Ireland’s carbon budgets?

posted 3 Jun 2022, 06:47 by Paul Price

The UN World Meteorological Organisation’s State of the Global Climate Report 2021, published on 18th 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 11th, 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.

The faster we reduce emissions the more positive the outcome will be for people and our wider environment. Emissions factors may be revised from time to time, but such revisions will not materially change the need for  immediate and radical emission reductions across all sectors of our society.

– By Barry McMullin with thanks to Karen Mahon and Paul Price for their input.

Revision of Forest emissions makes meeting Ireland's carbon budgets more difficult

posted 2 Jun 2022, 10:00 by Paul Price   [ updated 3 Jun 2022, 00:46 ]

Key Points
  • This post notes increased difficulties in meeting Ireland's carbon budgets due to land use, especially forest harvest, that are now magnified by revised emission factors for forestry on peat.
  • A 2022 EPA Inventory reduction of 2 MtCO2e in Forest removals increases net land use emissions overall value for the 2018 carbon budgeting base year, but Agriculture has been revised down by 0.9 MtCO2e. Therefore there is only a minor change in the total emissions for the 2018 base year for carbon budgeting indicating that a change in the carbon budgets already approved by the Oireachtas is not warranted. 
  • Charts below show how the increased Forest land emission factor changes results decreases Forest removals and increases net land use (LULUCF) emissions in all years since 1990 by 1–2 MtCO2e.
    • These inventory changes show that forestry on upland peat soils is far less beneficial for climate action than had been indicated previously in carbon accounting. 
  • The major new issue for meeting carbon budgets revealed by the new 2022 Projections is the ongoing and increasing land emissions to 2035, due to an even bigger forest harvest "carbon cliff" than previously anticipated being magnified by the Forest emission factor change.
  • Therefore, urgent policy attention to limiting forest harvest and peat extraction in the near-term is advised otherwise other Energy, Industry and Agriculture will require even more deeper mitigation achievement.

Charting the 2022 Projections relative to meeting Ireland's carbon budgets to 2035

The new 2022 EPA Greenhouse Gas Emissions Projections note a major revision of the 1990–2022 land use emissions, stating:
Research published since last year’s projections has led to a revision to the emission factor associated with forestry on organic (peat) soils and this has led to decreased removals/increased emissions associated with forest land for all periods, with over 2 Mt CO2 eq less removals in 2019.

In addition, the new Projections (p.8) note a serious failure to meet the agreed 5-year carbon budgets given the new sectoral projections. The bar charts below (click to enlarge) summarise the projected outcome for the WEM ("with existing measures") and WAM ("with additional measures" scenarios. The projected contribution from land use is substantially higher than anticipated due to the forestry harvest and emission factor issues. These projections therefore indicate that the Climate Action Plan requires immediate revision to increase ambition and achievement to meet the agreed carbon budgets, particularly in directing greater attention to limiting land use emissions.

Charting the revised 2022 Inventory land emissions compared to the 2021 Inventory

The Inventory change can clearly be seen by comparing the 2022 Inventory values with those from 2021 – this chart uses the data as shown in the Inventory's Table 2.1. The figure below for 1990–2020 annual land use emissions shows 2022 values as solid lines and the 2021 values for Forest land and Net Total LULUCF as dashed lines. Arrows show the impact of the inventory change from 2021 to 2022: the reduction in Forest land removals resulting in an increase in Net total LULUCF emissions.  
The updated science due the revised emission factor for forestry on organic soils shows that this issue is substantially greater than had been thought and, therefore, forestry has been of far less benefit in reducing emissions than had been thought. This suggests that continued planting of forests on uplands is of far less carbon sequestration benefit and that restricting harvest of these upland plantations may be beneficial in meeting the carbon budgets to 2035.

Unusually in Europe, overall Ireland's land use is a net source of emissions, not a sink, due to the effect of organic soils for Grasslands, Wetlands, and Forest lands,. The 2022 revision substantially increases the net source value to about 6.9 MtCO2e/yr (for each of 2018. 2019, and 2020) from about 4.8 MtCO2e in 2018. 

Implications for Ireland's carbon budgeting programme

Depending on how the Climate Change Advisory Council (CCAC) and the Government view matters in the context of Ireland's 2021 amendment of the climate Act, the 2.1 MtCO2e increase in LULUCF for 2018 may have implications for Ireland's carbon budgeting as the science has changed, thereby altering the 2018 base-year value for total emissions including land use. 

The table below compares the values for 2018 national sectors as given in the CCAC Carbon Budget Technical Report (CCAC-TR, October 2021) and compared to the revised valued in the 2022 Inventory (as given in the Total from CRF tab of the Chapter 2 trends Excel file, with LULUCF from the Fig. 2.10 LULUCF tab). The tables show minor differences except for Agriculture, for which the 2022 value is 0.9 MtCO2e lower than the CCAC-TR value, and LULUCF. which is 2.0 MtCO2e higher.

2018 sector GHG totals
EPA 2022
 Energy 37.0 36.8
 Industrial Processes 3.2 3.2
 Agriculture 22.3 21.4
LULUCF Emissions
 9.6 9.7
 LULUCF Removals -4.8-2.8
 Net LULUCF4.86.8
 Waste 1.0 0.9
Total (excluding LULUCF)  63.5 62.4
Total (including LULUCF) 


The Act mandated the CCAC to provide for five-year carbon budget to provide for a 51% reduction relative to the 2018 inventory emissions. Since the CCAC thereby defined the three five-year budgets for 2021–2035 to provide for this reduction from 2018 on the basis of the 2021 Inventory, and the Oireachtas has accepted them, it would seem that the set budgets to 2030 are therefore fixed under the Act as there is no provision in the Act to revise them. However, it may be that the CCAC and Government can decide to revise the base-year value based on the revised science and may also decide to redefine the 5-year budgets accordingly. 

If such a revision were to occur it would be important that at least the same percentage reduction occurs for the 2021–2025 and 2026–2030 budgets compared to five years of stable emissions at the 2018 level. Sustaining the 2018 level for 5-years would hypothetically have resulted in 342 MtCO2e. Compared to this the CCAC and Oireachtas-approved 2021-25 first carbon budget of 295 MtCO2e is a 14% emissions reduction (47 MtCO2e less). And for the 2026–2030 second carbon budget, the reduction is 41% lower (or 142 MtCO2e less) than the sustained 2018 level. 

The table below show what the resulting possible adjustments might look like by applying the same percent reduction relative to five-years at the 2018 rate.

Calculating possible CBs adjusted for revised 2018 value
2018 value x 5 years342346
CB1 for 2021–2025 defined/adjusted295299
CB2 for 2026–2030 defined/adjusted200203
CB3 for 2031–2035 defined/adjusted151153

This preliminary analysis indicates that there would be little change from the existing defined 5-year CO2e carbon budgets if the base-year data changed on the basis of the revised 2022 Inventory values for 2018. Also, the slight increase suggested by the adjusted values is not warranted for a developed nation in global equity terms, given that the effect is an increase in Ireland's claim on the remaining global carbon budget. Therefore, given the small adjustment, the time to make a change in the Oireachtas, and the potential for confusion in climate action, a change in the five-year carbon budgets as already defined does not appear to be warranted.  

However, far more importantly, as indicated by the new projections, the major new problem in meeting the defined carbon budgets appears to be a substantial increase in projected LULUCF emissions to 2030. Table 1 in the Projections report shows that projected net LULUCF emissions for WEM increase by +61.5% to 2030, or for WAM by +20.9% relative to 2018,. Moreover, these large percentage increases relate to an increased 2018 net LULUCF value of 6.8 MtCO2e/yr.  The LULUCF increases directly imply an increased LULUCF sectoral ceiling and so other sectoral ceilings must further decrease accordingly to make up for the failure to cut net land use emissions unless strong land use policy regulation is enabled. 

In short, the revised Forest GHG inventory time series raises important questions for Ireland's carbon budgeting base year emissions definition and achievement of the defined budgets. The analysis here suggest that there is insufficient basis to change the carbon budgets provided by the CCAC and confirmed by the Oireachtas. Much more important is the apparent substantial increase in the 2022 projected land use emissions up to 2035 compared to the CCAC-TR values. 

A projected increase in forest plantation harvest relative to past planting and afforestation was described in the CCAC-TR (p. 86) as the forestry "carbon cliff" given the reduction in forest CO2 removals. The 2022 Projections imply that this "carbon cliff" is even larger than previously anticipated and makes meeting the carbon budgets considerably more difficult. Therefore, limiting LULUCF emissions is now a far greater issue for climate action policy revision and requires stronger policies and measures in the 2022 Climate Action Plan. Urgent policy measures to limit forest harvest and peat extraction would appear to be required to avoid significantly increased mitigation costs in energy and agriculture if the carbon budgets are to be met.

Additional charts of land use emissions, removals and net LULUCF GHGs: annual, and cumulative from 1990

What matters for climate change temperature impact in land use are cumulative CO2 emissions. In land use CO2 is by far the largest part of the recorded or projected CO2e.

The chart below shows a digest of the 2022 Inventory annual land use time series for 1990–2020 as solid lines, separating total land use removals shown in blue (mostly due to "Forest land" and "Harvested Wood Products") and total land use emissions shown in red (mostly due to "Grasslands" and "Wetlands". The Net Total shown in black is given by emissions minus removals, reaching 6.9 MtCO2e/year in 2018. Dashed lines show the corresponding 2021 inventory analysis time series data. Arrows again show the change in 2019 value from the 2021 to the 2022 Inventory.

The chart below sums the cumulative total since 1990 based on the same time series values shown in the annual chart above. Cumulative land emissions since 1990 have reached 299 MtCO2e versus removals of 83 MtCO2e, resulting in a net source of 216 MtCO2e. The adjustment in Forest land emissions means that this value is nearly 50 MtCO2e higher than shown in the 2021 Inventory. This is a substantial net loss of carbon from Irish land use over time, showing that only if net annual land use moved from emissions to removals would these past land carbon stocks start to be refilled. In other words land carbon sequestration will not meaningfully offset ongoing emissions in other sectors, they need to achieve actual GHG emissions reductions. 

To reach net zero annual land use emissions would require a major change in land use policy particularly directed at limiting farming and forestry harvest and planting on all organic soils, and limiting peat extraction to near-zero. Without such measures any slow increases in sequestration rate through afforestation on mineral soils and rewetting of peatland will have comparatively small effect given the ongoing land carbon losses being accounted from Grasslands and Wetlands and the reduced removals from Forestland. 

The substantial reduction in inventory annual and cumulative forest removals due to the impact of past planting on organic soils indicates that any plans for further afforestation on uplands needs to be reconsidered as a matter of urgency. The need for focused land use planning to restrict activity and drainage on all organic soils is even more apparent given the revised emission factors. A land use plan backed by strong policy support could have highly beneficial environmental and climate outcomes and guide a revision to forestry and farming practices aligned with international commitments. 

Aeromobility and climate: it's complicated!

posted 21 Mar 2022, 11:31 by Barry McMullin   [ updated 21 Mar 2022, 11:32 ]

[Participant contribution to the online workshop Academic aeromobility in a post-pandemic future organised by the Tyndall Centre, Manchester, 22 March 2022. This is a lightly edited version of an email response to a colleague who, reviewing the possibilities for “flying less”, asked me to “… sketch out the issues re aviation emissions compared to other transport forms or to point me to some literature that would be helpful.” What follows is my fairly unstructured brain dump…]

Flying is certainly a very greenhouse-gas emissions-intensive form of transport. Nonetheless it is complicated to compare it with other transport options with any precision. For many reasons:

  • Point-to-point flying will use the shortest possible route, whereas surface travel for the same journey will generally be longer. Of course, if a direct flight is not available, then the multi-hop flight distance for a particular trip may be longer than surface.

  • The majority of fuel consumption in most powered transport is to move the “vehicle” (airplane, train, bus, car…) rather than the passengers. So the “emissions per passenger” depends critically on the “occupancy” (relative to the carriage capacity of the vehicle). But this varies hugely from case to case. So that makes deciding on emissions benefits for different travel modes on a “case by case” basis very complex and difficult. (Mind you: the question of higher “class” air travel does significantly skew the occupancy question: obviously a given aircraft can only carry fewer business class, or much fewer first class, passengers, so the “emissions per passenger” go up in fairly exact proportion.)

  • Direct comparison is further complicated by the fact that flying doesn’t just release greenhouse gases, especially CO2 (like all fossil fuel burning, including fossil-fueled surface vehicles), but it does so at high altitude. There is good science suggesting that this makes the climate impact (per tonne or litre of fuel burned) significantly greater for flying than surface travel - perhaps as much as a factor of two or more.

  • It can be argued (and is by many people) that “the airplane will be flying anyway”, so the emissions associated with having one more or less passenger is negligible. Or putting that the other way around, by choosing to, say, drive a car (especially single occupancy) for a given trip, instead of flying, total emissions “associated” with the trip (car + passenger, since the plane flies “anyway”) may actually be higher rather than lower. So it’s actually better to fly than not (if that keeps occupancy factors on planes high)! But against that, of course, one can argue that it’s the aggregation of trips that ultimately matters (Anderson’s “systems level”). So individual decisions not to fly, if done consistently and at scale, would, by sheer economics, ultimately result in fewer actual planes being scheduled to fly, and thus consistently lower emissions. Though, on its own, that’s still a weakish argument: if all those people still travel as far and as often, but now, in, say, single occupancy cars, then the total emissions are likely substantially higher.

  • There again, that was comparing flying with car travel, on the presumption that the car wouldn’t otherwise travel. But that won’t apply if comparing flying to travel on some other “shared” service (bus, train, ferry) where the other vehicle would also be travelling anyway.

  • An alternative way of coming at this then is to assume that we are working with some fixed total amount of passenger-km, and asking whether it makes sense to try to minimise the proportion of that undertaken by flying, as a long term, “system” objective? Viewed that way, a critical consideration is that, for surface travel (including high speed rail) there are existing, more-or-less mature, technical options to use non-fossil energy to power this (specifically, electricity from non-fossil fuel sources - solar, wind, hydro, nuclear…). For the moment only a minority of surface travel is actually powered in this way: but at least there is the prospect of progressively decarbonising the electricity source in this case. But there is little serious prospect of decarbonising flying, for at least several decades into the future (albeit, I am discounting aviation lobby arguments here, which rest on use of biofuels and/or “offsetting”). That being the case, one can say there is a strong argument that, as long as flying is fossil fueled, it just has to be abandoned. (Maybe, sometime in the future, we’ll have serious non-fossil-fuel options for flying, and maybe then flying can come back into use: but right now, full decarbonisation of energy logically requires that we stop flying.)

  • OK, so that was all premised on a certain “fixed” amount of travel (total passenger-km) and asking whether some or all of it should be switched away from flying. But perhaps the “core” issue here is not “flying” per se, but the total amount of (fossil fueled) travel by any means: the total passenger-km undertaken. While emissions will vary somewhat (in complex and sometimes counter-intuitive ways) according to modal choices, the biggest, most reliable, gain would be by reducing total (fossil-fuel-powered) travel by all modes.

  • But even then, we still come back to flying as a special case. It is precisely because it is so fast, that it enables, facilitates, and encourages much more total passenger-km than would be likely to be undertaken if only slower modes were available. OK, high speed rail might be subject to a similar criticism, but then we come back to the fact that, at least in principle, rail can be very largely decarbonised whereas, as yet, flying can’t. So further growth in high speed rail travel is not inextricably tied to growth in emissions in the way that air travel is.

  • Global inequity (in consumption and in climate change responsibility) is implicit in everything above: but I think it’s fair to say that flying raises the equity question in a particularly acute form: the sheer pointed insult of rich people flying over poor and vulnerable people, blithly contributing further to their threats and risks, is so grotesque that to contemplate it seriously seems almost unbearable (so I, like most of the global “jet set”, just don’t contemplate it at all).

  • And taking all those things together, we just have the sheer symbolism, at least when it comes to individuals, but especially organisations, that claim to be working to fight climate change. While the best thing for us to do is minimise our absolute consumption impact (including passenger-km) overall, flying is such an extravagantly intensive form of climate pollution that engaging in it just can’t but undermine the organisational message.

As I said, it’s complicated!

Some additional references:

Finally, to everyone who happens to chance on this post, good luck pursuing flying less measures in your own local organisational context, whatever that may be!

Paris-Consistent Carbon Budgeting 1-pager & literature review [CCAC Carbon Budgeting Fellowship Blogpost 4]

posted 19 Jul 2021, 05:06 by Paul Price   [ updated 19 Jul 2021, 05:21 ]

As part of his Carbon Budgeting Fellowship, Paul Price prepared a carbon budgeting literature review and a one-page summary for Ireland's Climate Change Advisory Council. Submitted in April 2021, minor revisions in July 2021 are included in these linked DCU website versions.

The literature review is entitled "Assessing Ireland's fair contribution to the global effort to limit global warming to 1.5ºC or well below 2ºC". This will have increased relevance for Ireland with the passing of Ireland's amended Climate Bill which sets out the requirement for a national carbon budgeting programme consistent with the Paris Agreement's Article 2 commitments to equitable implementation and alignment with the 1.5ºC and well below 2ºC temperature targets.

A key conclusion of this literature review is the importance of including non-CO2 gases as well as CO2 in carbon budgeting. Strengthened science over the past five years shows how non-CO2 GHGs can be included in global and national carbon budgeting by using "CO2 warming equivalent" measures via "step pulse GHG equivalence metrics, such as GWP*. 

This conclusion is especially important for wealthier nations, which are very rapidly exhausting even a "minimally equitable", Paris-aligned carbon budget and also for nations with a high proportion of methane and nitrous oxide emissions. Both are true for Ireland, therefore this review sets out an estimated range for Ireland's "NCQ*", its national carbon quota based on aggregated warming due to CO2, N2O and CH4.

From the conclusion:

It is important to note though that even if, or once they are exceeded, the Paris Agreement temperature targets remain salient, demanding a focus by Parties on keeping the temperature peak as low as possible, and on reversing any overshoot as quickly as possible. To be consistent with the Paris Agreement focus on equitable implementation of mitigation action aligned with the 1.5ºC and well below 2ºC temperature targets, climate action in Ireland now requires: radical cuts in fossil fuel use to net zero and then net negative as soon as possible; maintaining and increasing land carbon sinks, and sustained and permanent deep cuts in methane and nitrous oxide emissions due to agriculture. Policies and measures continue to fall far short of delivering on these objectives.

The GWP* metric and methane mitigation potential [CCAC Carbon Budgeting Fellowship Blogpost 3]

posted 1 Mar 2021, 02:35 by Paul Price   [ updated 3 Mar 2021, 09:06 by Barry McMullin ]

  • Reducing fossil fuel usage and carbon dioxide emissions is the priority for climate action. However, Ireland also has comparatively high emissions of methane and nitrous oxide emissions, so it is essential to understand their effect on national carbon budgets and transition pathways aligned with the Paris Agreement. 

  • A new metric called GWP* enables methane assessment and its inclusion in aggregate greenhouse gas budgets with carbon dioxide and nitrous oxide.

  • Use of the GWP* metric shows that permanently increasing the methane flow of annual emissions by 1 tCH4/yr equates to a substantial warming increase, equivalent to a one-off addition of 2400 tCO2 to the atmosphere. The reverse is true for a decrease in methane flow. A permanent cut by 1tCH4/yr equates to a one-off removal of 2400 tCO2 from the atmosphere and warming reduction (not “cooling”).

  • Therefore, using GWP*, the 86 ktCH4/yr increase in Ireland’s methane annual emissions between 2010 and 2019 (mostly from ruminant agriculture) is an added warming contribution equivalent to a one-off addition of over 200 MtCO2, equal to an additional 17 years of current transport emissions.

Ongoing methane emissions do contribute to global warming

Sustained cuts in total Ireland’s methane emissions would enable considerable warming reductions that could be very important in aligning national carbon budgets of greenhouse gas (GHG) emissions with equitably meeting the Paris Agreement temperature targets as shown in our EPA report (McMullin and Price, 2020). A very useful new method of assessing the global warming impact of methane is called GWP*, pronounced ‘GWP star’ (Lynch et al., 2020). Using this formula enables useful analysis of the effect of methane mitigation in alternative low carbon transition pathways without needing a more detailed climate model to assess warming impact. 

However, the usage and implications of GWP* are commonly being misinterpreted and misrepresented. Many media articles and some experts have been wrongly suggesting that GWP* shows that a constant or a very slowly declining flow of methane is “not contributing to global warming”. This is not correct. 

In reality, methane is a potent greenhouse gas (GHG) and a continued flow of it keeps on ‘topping up’ the raised level of atmospheric methane concentration due to a source, even as methane emitted earlier decays. It is therefore misleading to suggest that the short 10-year [half-]life of methane implies that methane does not require serious mitigation attention. Unless a source stops emitting methane completely, it is of course still “contributing to warming” because the ongoing emissions are continuing to sustain a raised atmospheric methane concentration and resultant raised global temperature. It is very important to understand that the behaviour of a sustained or changing flow of methane is very different from that of a single pulse emission (or year). 

GWP* shows relative change

As presented by the Oxford University team that developed it, the GWP* metric only registers relative change over the past 20 years. After showing an initial 20 years of rapid warming due to a new source, it does not register any change in the raised level of warming from a now stable methane flow. 

This means that the GWP* metric does not show the sustained flow contribution to warming from a source; for each year it only shows the change from 20 years previously. Unfortunately this formula construction means that the presented version of the metric does not immediately reveal the full methane mitigation potential that could be available for climate action assessment in terms of trade-offs between sectors and different GHGs. 

This is important because in low carbon transition policy analysis to assess different pathway options and trade-offs we need to compare the full mitigation potential of different sectors and the different costs of alternatives that can affect the available national carbon quota for energy transition in line with Paris targets. As permanent cuts in methane emission achieves rapid and certain warming reduction equating to negative emissions, GWP* can be used to compare the costs and issues of this option with the slower and less certain warming reduction that can potentially be achieved by carbon dioxide removal through forestry or as yet undeveloped methods such as bioenergy with carbon capture and storage.

Using the appropriate GWP100 values for GWP*

Contrary to many reports, the GWP* metric does not introduce any new scientific understanding of the climate system behaviour of methane. What the Oxford University team and their peer-reviewed GWP* papers have done is to cleverly define (Allen et al., 2018) and then refine (Cain et al., 2019; Lynch et al., 2020) a formula, as shown in Note 1, to approximate the actual atmospheric warming behaviour of methane flows accurately. 

The metric conveniently utilises the already-existing time series of methane emissions as submitted by nations to the UNFCCC as part of global emissions accounting. The accounted values for GWP100 (Global Warming Potential over 100 years) in these national submissions use a factor of 25 to indicate that 1 tonne of methane per year has the equivalent to 25 tonnes of carbon dioxide (so using GWP100 1tCH4 = 25 tCO2eq). Unhelpfully for scientific use the GWP100 values used in emissions reporting are outdated and updated science has established a GWP100 value of 32 for biogenic methane, with a slightly higher value for fossil methane. The Oxford group use a GWP100 value of 32 for methane in GWP* calculation of a CO2 warming equivalent (CO2we), so the CO2eq values given in national accounts need to be multiplied by 32/25 before use for GWP* calculations.

Methane’s warming impacts: stock effect and rate of flow effect

Methane emission has two distinct global heating effects, a long-term stock effect and substantial and relatively fast action rate of flow effect (fractionally denoted in the GWP* formula by the s and r values, respectively). 

The stock effect can be considered to be cumulative on the time scale of climate action, adding up to more warming year on year. (This effect is due to the slow ocean response to the large initial atmospheric warming impact from an emission, so contrary to some reports, this methane stock effect not due to residual CO2 from methane breakdown.) The stock component of methane emissions is estimated by GWP* at one quarter of GWP100 methane emissions. Therefore given Ireland’s 2019 methane emissions of 13.7 MtCO2eq (93% from ruminant agriculture), the corresponding stock value in GWP* terms is 3.7 MtCO2we, which is still substantial. For the long-term warming effect of agriculture this is additional to 7 MtCO2we in current annual nitrous oxide emissions. 

The rate of flow effect is very different and can have very substantial impacts on the overall methane warming impact from a source: if annual methane emissions are increasing then the resultant warming increases in addition to the stock effect; if methane emissions are decreasing slowly, by 0.32%, per year then the rate effect’s warming reduction exactly cancels out the stock effect warming increase, resulting in no change in warming; and if the flow emissions are decreasing more quickly than this then there is a warming reduction. Warming due to a source only stops if the source stops emitting altogether.

Changes in methane emission have a big warming impact

Examining the GWP* formula shows that the rate of flow effect is determined by a product of [GWPH x r x H] multiplied by the methane emissions in tonnes. Using r = 0.75, the time horizon H of 100 years for the GWP100 value of 32, this equates to 32 x 0.75 x 100 = 2400 CO2we/tCH4. (As presented by the Oxford team, the formula divides the change by a Δt of 20 years to average out the warming impact of a new flow as occurs in reality.) 

This means that permanently increasing methane flow by 1 tCH4/yr equates to a warming increase equivalent to a one-off addition of 2400 tCO2 to the atmosphere. 

The reverse is true for a decrease in methane flow, a permanent cut by 1tCH4/yr equates to a one-off removal of 2400 tCO2 from the atmosphere.

This very large CO2 warming equivalence of a small sustained change in methane flow shows that changes in methane emissions can have a very large effect on aggravating or mitigating climate change. GWP* correctly shows sustained reductions greater than 0.32% per year as having negative CO2we emissions. This is a great improvement on GWP100 which still shows positive CO2eq emissions for methane even if the rate is decreasing, so GWP100 fails to show the warming reduction related to reducing methane flows. 

It is important to note that short time GWP* time series of annual CO2we values can be highly variable and easily misinterpreted because GWP* incorporates a 20 year lag to reflect the incremental delayed warming impact of a year’s emissions (peak warming is 12 years after emission). Annual methane emissions in Ireland, shown by GWP100, decreased from 1998 until 2011 and increased due to dairy expansion thereafter, and, as a result, GWP* annual values went negative due to the decrease and have only become positive since 2015. Our recent working paper comparing recent agricultural methane increases with a mitigation alternative clearly shows the effect of this lag (Price and McMullin, 2020).

GWP* enables the methane to be included in aggregate all-GHG budgets based on cumulative CO2we emissions from a defined year to assess warming. This allows whole economy societal carbon budgeting to assess the warming impact of different policy options in terms of GHG and costs between different sectors.

Using GWP* to show the full (technical) methane mitigation potential

Informatively, we can use the above GWP* flow rate equivalent of 1 tCH4/yr = 2400 tCO2we to estimate a stable flow equivalent for each year. This is shown in the chart below, which excludes the stock effect and the smoothing achieved by GWP* value but helpfully reveals an approximation of the full amount of warming sustained by methane emissions rate of flow. For each time series year, the tonnes of methane emissions (tCH4) is multiplied by 2400 to get a value for each year reflecting the hypothetical case of warming being sustained at this level of flow. 

Chart, line chart  Description automatically generated

This shows that the level of warming being sustained by Ireland’s methane emissions is very substantial, approximately equating to a one-off addition of 1400 MtCO2we, over 1300 MtCO2we of which is from cattle and sheep. Compared to the rise in agricultural methane of over 200 MtCO2we from 2010 to 2020 using the GWP* factor to show a stable flow impact, looking at the standard GWP100 reporting of agricultural methane shows only a rise of about 2 MtCO2eq. 

In Ireland, 1 tCH4/yr is equivalent to the annual methane emissions of more than 7 dairy cows; since dairy cow numbers have increased by over 400,000 head over the past decade the resultant warming equates to a one-off addition of about 140 MtCO2, indicating that the past decade of dairy expansion has resulted in a warming equivalent to an additional 12 years of transport CO2 emissions. Adding a single dairy cow has the same equivalent impact on global temperature as a one-off release of 320 tonnes of CO2, the same as driving a new car 2.8 million kilometres. Permanently removing a single dairy cow from production has the reverse, warming reduction impact.

Conclusion: methane mitigation has substantial impact on carbon budgets

As shown in our previous research, using GWP* can aggregate all-GHGs into cumulative CO2 warming equivalent values to enable assessment of the warming due to alternative policy pathways. Changing methane emissions has a very substantial effect on Ireland’s rapidly depleting remaining carbon budget in terms of equitably aligning climate action with the Paris Agreement:

Scenarios with higher sustained CH4 reduction rates [than -1% per year] would greatly ease the required net CO2 mitigation rate and limit overshoot of near-term climate targets. (McMullin and Price, 2020)

Note 1: Extract below from Cain et al. , showing the GWP* formula used to calculate the “CO2 warming equivalent” emissions for a single year: 

Text  Description automatically generated


Allen, M.R., Shine, K.P., Fuglestvedt, J.S., Millar, R.J., Cain, M., Frame, D.J., Macey, A.H., 2018. A solution to the misrepresentations of CO₂-equivalent emissions of short-lived climate pollutants under ambitious mitigation. Npj Clim. Atmospheric Sci. 1, 16.

Cain, M., Lynch, J., Allen, M.R., Fuglestvedt, J.S., Frame, D.J., Macey, A.H., 2019. Improved calculation of warming-equivalent emissions for short-lived climate pollutants. NPJ Clim. Atmospheric Sci. 2, 1–7.

Lynch, J., Cain, M., Pierrehumbert, R., Allen, M., 2020. Demonstrating GWP*: a means of reporting warming-equivalent emissions that captures the contrasting impacts of short- and long-lived climate pollutants. Environ. Res. Lett. 15, 044023.

McMullin, B., Price, P., 2020. Synthesis of Literature and Preliminary Modelling Relevant to Society-wide Scenarios for Effective Climate Change Mitigation in Ireland  2016-CCRP-MS.36 (EPA Research Report No. 352). Environmental Protection Agency.

Price, P.R., McMullin, B., 2020. Assessing methane (CH4) from Irish agriculture in climate policy 2005–2020 using the GWP100 and GWP* greenhouse gas (GHG) equivalence metrics 2.

What is meant by a "stable cattle herd"? [CCAC Carbon Budgeting Fellowship Blogpost 2]

posted 8 Feb 2021, 05:29 by Paul Price   [ updated 9 Feb 2021, 04:25 ]

  • The Ag Climatise roadmap, Government’s plan to reduce agricultural emissions, is premised on a “stable herd”, but no reference year or level has yet been stated. 

  • Crucially, the total herd number of beef and dairy animals does not provide meaningful information for climate action policy as dairy cows have much greater greenhouse gas emissions than beef animals. Also, within the total, the ratio of dairy to beef numbers changes through time. 

  • A more useful gauge is to state the reference year and GHG target level, then assess relative dairy and beef cattle numbers based on their annual per head emissions.

  • A straightforward calculation, based on the EPA 2020 National Inventory Report (NIR) data, indicates that annual total cattle methane has risen by 1.15 MtCO2eq since 2005, which is the reference year for mitigation of non-traded emissions. In terms of methane, for a stable herd relative to 2005, a reduction of 362,000 dairy cows or 940,000 beef cattle would be necessary to compensate for the rise in cattle methane emissions. 

  • To maintain a “stable herd” of cattle in Ireland by stabilising methane emissions from 2018, every addition of 10 dairy cows would equate to requiring a reduction in the beef numbers of 26 animals.

  • The new 2021 Inventory available in April will update dairy cow and beef per head figures for methane emissions and nitrogen excretion, so this blogpost will need to be updated to allow for the EPA recalculation.

Climate action and agriculture

Ireland has a comparatively large fraction of greenhouse gases (GHGs) from agriculture, particularly the potent global warming gases nitrous oxide (N2O) and methane (CH4). Predominantly this climate pollution is related to the number of dairy and beef cattle, which are significant sources of methane and nitrous oxide. These emissions are correlated with the level of nutrient inputs, particularly reactive nitrogen from chemical fertiliser used to boost grass growth and in concentrate feeds. The Irish government’s recently published Ag Climatise ‘roadmap’ states:

“It is well understood that emissions in agriculture have two key drivers – livestock numbers and fertiliser use.”

Although not directly referenced in the Ag Climatise document itself, the Government has strongly asserted that “the Ag Climatise roadmap is based on the premise of a stable herd”. By contrast the Climate Change Advisory Council has advised that “[a] reduction in the national herd is necessary to reduce absolute greenhouse gas emissions” (CCAC, 2019). The idea of a stable herd has now become a contentious topic in agricultural policy discussion in regard to the possible need for cap or reductions in cattle numbers. 

This blogpost (to be updated based on 2021 EPA data to be released in March) takes a preliminary look in methane-only terms at how we could calculate a "stable cattle herd" in a ‘climate smart’ way relative to a given baseline year.

At least, three important questions arise in regard to the assertion of a stable herd as a premise for climate action: 

  1. What year are we using as a benchmark for stable herd in respect to climate action?

    • 2005 is the EU reference year basis for non-traded emissions including agriculture. Given the Ag Climatise emphasis is on reducing GHGs in accord with EU policy it makes sense to use 2005 as the basis for assessing Irish agricultural emissions.

  2. Given the big difference in GHG emissions between beef and dairy cattle, how can we judge the herd size in GHG terms if the beef:dairy ratio changes through time?

    • Below, this blogpost outlines a straightforward calculation based on emission totals by animal type and the ratio of dairy to beef per head annual methane, based on animal numbers and per head methane emissions given in the EPA National Inventory Report 2020.

  3. What “stable herd” target level might be consistent with societal pathways aligned with Ireland’s ‘fair share’ of a carbon budget for Paris Agreement’s temperature targets?

    • In a recently published EPA Report, Barry McMullin and I looked at the trade-offs between carbon dioxide (CO2) and non-CO2 GHGs for Ireland in society-wide scenarios for effective climate change mitigation (McMullin and Price, 2020). The report’s indicative scenarios make it clear that substantial reductions in methane, 93% from agriculture, are essential to limiting overshoot of Ireland’s all-GHG carbon budget (in addition to the primary climate action focus on reducing fossil fuel usage rapidly to cut CO2 emissions). From this top-down carbon budget basis, it is apparent that a target “stable herd” would need to be much smaller than it is currently – as much as 50% reduction by 2050.

Adjusting herd size for dairy vs. beef differences is essential

Over time, the total numbers and inputs for beef animals and dairy cows are very different and the dairy to beef numbers ratio changes over time. Therefore, the total herd number (simply adding up all cattle including beef and dairy animals), or citing changes in this total, does not provide meaningful information to guide decision-makers in limiting cattle-related GHG emissions. A different measure is needed.

Using the 2020 National Inventory Report data (EPA, 2020a, Annex 3.3), Table 1 shows derived total methane emissions and numbers for all cattle, and sub-totals for dairy and beef cattle, for the 2005–2018 period. Dairy cattle methane increased by 45% and Other cattle methane decreased by 3%, resulting in an overall increase in cattle methane of 11% (46ktCH4/yr) from 418 ktCH4 in 2005 to 463 ktCH4 in 2018.

Table 1. Methane emissions for dairy and beef cattle based on 2020 NIR figures. This table will need to be updated based on revised data for the 2021 NIR that will significantly change the total methane emission and per head intensity values.

2018 ktCH4


2018 ktCH4/


Change ktCH4

% change

2005 number

2018  number

2005 kgCH4





Dairy Cattle









Other Cattle 









Total Cattle







As shown in Table 1, dividing total methane by the number of animals gives the average annual per head methane intensity: for 2005 and 2018, for dairy, 121.6 rising nearly 4% to 126.5 kgCH4/head; for beef, 49.4 falling 1.6% to 48.6 kgCH4/head. As shown graphically in Figure 1, this means that a dairy cow emits 2.6 times the average methane emissions of other cattle (beef cattle including sucklers, with dairy heifers). 

Chart, bar chart  Description automatically generated

Figure 1. As of 2018, dairy cows have 2.6 times the annual methane emissions of beef cattle.

In other words, if further dairy expansion is to occur from 2018 onward then every addition of 10 dairy cows would equate to a reduction in the beef herd of 26 beef animals to prevent a rise in methane emissions. Relative to 2018, the 2027 Sectoral Roadmap: Dairy (Teagasc, 2020) targets an additional 225,000 cows, with 40,000 already added in 2019. 

These values reflect the 2020 NIR, but toward the 2021 NIR the EPA has undertaken a significant recalculation of annual per head cattle methane emissions and excreted nitrogen data as shown in presentation of provisional 2019 emissions (EPA, 2020b), based on updated research (O’Brien and Shalloo, 2019). The provisional data for agriculture, resulting in 2018 total sectoral emissions rising by over 1 MtCO2eq will be finalised for submission by 15 March 2021. Once the 2021 NIR data is updated this blogpost will be revised and a Working Paper will set out the issues raised here in more detail.

Table 2. Reduction in Other cattle required to stabilise cattle methane emissions due to increased dairy cow numbers targeted by the Teagasc 2027 Sectoral Roadmap Dairy, relative to 2018 and 2005.


Relative to 2018 methane emissions

Relative to 2005 methane emissions

Rise in dairy cattle Teagasc roadmap

Rise in CH4 due to higher dairy cattle numbers (in ktCH4/yr)

Corresponding reduction in Other cattle

Rise in dairy cattle Teagasc roadmap

Rise in agri CH4 relative to 2005 (in ktCH4/yr)

Corresponding reduction in Other cattle








By 2027








Teagasc (2017) have stated that stabilising methane emissions is particularly important. If so then beef cattle numbers must fall by the number of added dairy cows multiplied by the dairy to beef ratio of per head annual emissions:

·       Relative to 2018, stabilising methane based on the Teagasc roadmap dairy cow numbers would require a reduction in Other cattle of 104,000 in 2019 and 585,000 by 2027.

·       Relative to 2005, stabilising methane based on the roadmap numbers would require a reduction in Other cattle of 585,179 in 2019 and 1,525,506 by 2027.

Equivalent reductions in Other cattle would be greater than these values if annual per head emissions continue to increase for dairy cows and decrease for beef cattle. Total dairy methane is rising more quickly than total cow numbers because annual methane (and milk) per head is rising. Therefore, total dairy methane emissions are more linearly related to total milk production than to dairy cow numbers.

Coherent agricultural and climate policy requires both dairy and beef numbers based on a clearly stated climate action target

If policy-relevant statements regarding 'stable herd' cattle numbers are to be coherent with climate mitigation policy then the reference year, the climate target (stabilising methane or reducing by an amount and date) and the target rationale (EU or Paris-aligned or other) need to be clearly specified. On this basis alternative corresponding dairy and beef numbers to stay within a stable or declining methane limit can be calculated using the annual per head emission data. Adopting such a straightforward approach to coherent agricultural and climate policy would ease carbon budgeting analysis in assessing alternative transition pathways for agriculture and society.  

The calculations above do not imply that any recent-basis estimates of stable cattle numbers, adjusted for methane or not, are aligned with Ireland’s fair share in meeting the Paris Agreement targets. Our recent EPA Report, including preliminary societal mitigation pathways to meet a Paris aligned carbon budget indicates that substantial and sustained reductions in ruminant production level are required to avoid very substantial overshoot of Ireland’s all-GHG carbon budget. Policy-relevant statements could also reflect this understanding.

As noted above, this blogpost is only preliminary. Once the 2021 NIR data is updated this blogpost will be revised and a Working Paper will set out the issues raised here in more detail.


CCAC, 2019. Annual Review 2019 (Annual report). Climate Change Advisory Council [Ireland].

EPA, 2020a. IRELAND NATIONAL INVENTORY REPORT 2020. Environmental Protection Agency (Ireland).

EPA, 2020b. EPA’s James Murphy presents “Improvements to the Agriculture Inventory.”

McMullin, B., Price, P., 2020. Synthesis of Literature and Preliminary Modelling Relevant to Society-wide Scenarios for Effective Climate Change Mitigation in Ireland  2016-CCRP-MS.36 (EPA Research Report No. 352). Environmental Protection Agency.

O’Brien, D., Shalloo, L., 2019. A Review of Livestock Methane Emission Factors (Research report No. 288), EPA Research. Teagasc.

Teagasc, 2020. 2027 SECTORAL ROAD MAP: DAIRY.

Teagasc, 2017. 2017 - Reducing Greenhouse Gas Emissions from Agriculture - Teagasc | Agriculture and Food Development Authority.

About this Carbon Budgeting Fellowship #CCAC_Fship_DCU [Blogpost 1]

posted 8 Feb 2021, 05:25 by Paul Price

Carbon budget research has profound implications for the national priority of achieving a cost-effective, low carbon transition pathway to 2050, aligned with policy accepting Ireland does its ‘fair-share’ to meet the Paris Agreement and the SDGs. 


Beginning in January 2021, working through Dublin City University, I will be researching and advising on Carbon Budgeting as a Fellow to the Climate Change Advisory Council (CCAC) as funded for a two-year period by EPA Research. For the CCAC, its Secretariat will channel requests to Fellows and provide Steering Groups to support them.  


The DCU Supervisors for my Fellowship research are Prof. Barry McMullin and Dr. Aideen O'Dochartaigh so this will also be very much a team effort. Barry and I have worked on two EPA reports on societal climate mitigation for Ireland, one looking at the potential for negative emissions technologies in the context of CO2-only carbon budgets, and a second report extending our literature review and carbon budget modelling to non-CO2 emissions. Aideen is an Assistant Professor in Accounting at DCU Business School with particular expertise in business-sector sustainability accounting and bioeconomy research.


The exact focus of the Fellowship research over the two years will likely depend on the exact content of the upcoming revision of the 2015 Climate Action and Low Carbon Development Act and the new requirements placed on the CCAC as a result of the legislation and developing Government climate change policies. To inform its advice on climate action the CCAC will be looking to the academically independent advice of the new Fellows to provide evidence-based inputs.


For now my work will focus on the Work Packages set out in the Fellowship as approved for funding under the title Carbon budgets to inform climate action: A society-wide, integrated GHG quota and accounting perspective. The research is divided into four work packages, each covering about six months work: 

1.  Agriculture and land use pathways within society-wide transition;

2.  Integrated carbon budget assessment of existing policy emissions scenarios;

3.  Design and assessment of alternative additional integrated emissions scenarios (including negative emissions and methane mitigation);

4.  Integrating national and business-sector carbon budget accounting.


Extending previous carbon budget, mitigation pathway and carbon accounting research the work packages aims to provide finer grained, sectoral-level research and modelling to help the Council provide stakeholders with essential carbon budget context for effective mitigation action.

The Aviation Industry, the Covid-19 Pandemic & Climate Change - Part 2

posted 30 Jun 2020, 02:49 by ECRN ECRN   [ updated 26 Feb 2021, 04:57 ]

The ECRN has the privilege of connecting many renowned researchers across a wide variety of disciplines. All of them are united by a commitment to educate and innovate in the field of energy and climate research. In our new podcast series, we'll be speaking to our members about their work. Our aim is to make their complex but vital work accessible to a general audience.

Dr Colm Kearns hosts a discussion between aviation expert Dr Cathal Guiomard and engineer and emissions expert Professor Barry McMullin about the impact of the Covid-19 pandemic on the aviation industry and the long term ramifications this has for climate change. They debate the merits and detriments of various strategies mooted to balance vibrant aviation with combating climate change. This is Part 2 of a 2 Part Series.

The Aviation Industry, the Covid-19 Pandemic & Climate Change - Part 1

posted 16 Jun 2020, 04:21 by ECRN ECRN   [ updated 26 Feb 2021, 04:57 ]

The ECRN has the privilege of connecting many renowned researchers across a wide variety of disciplines. All of them are united by a commitment to educate and innovate in the field of energy and climate research. In our new podcast series, we'll be speaking to our members about their work. Our aim is to make their complex but vital work accessible to a general audience.

Dr Colm Kearns hosts a discussion between aviation expert Dr Cathal Guiomard and engineer and emissions expert Professor Barry McMullin about the impact of the Covid-19 pandemic on the aviation industry and the long term ramifications this has for climate change. They debate the merits and detriments of various strategies mooted to balance vibrant aviation with combating climate change. This is Part 1 of a 2 Part Series.

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