Brian Leddin (Limerick City, Green Party) | Oireachtas source

I welcome Professors O'Mara and Boyle. Indeed, I extend the good wishes that my colleagues have sent to Professor Boyle and I wish him well in the next few months before he finishes up. I thank him for his work with Teagasc over the years.

Professors O'Mara and Boyle have acknowledged the beef versus dairy situation. It seems that until the 2010s our emissions were reducing, largely because the suckler herd was reducing and then it turned around. Now we have a situation wherein any gains that we have made through the reduction in the suckler herd have been unfortunately negatively offset by the increase in the dairy herd. Had that reduction continued, we would be at something like 15 megatonnes of agricultural emissions per year instead of 21 or so. The professors have acknowledged that and it is a most is significant point on which we should probably dwell more - perhaps not in this session but in further sessions.

The professors have mentioned an EU study which shows Irish milk to have the joint lowest carbon footprint in the EU.

Bear in mind 90% of our milk product is exported. Does the study include the carbon footprint as a result of export?

The same section in the statement refers to the international context. The United Nations understands the biggest threat to global food security is climate change. Many of our development agencies such as Trócaire and Concern are working with some of the poorest communities around the world which suffer extreme hardship and famine as a result of climate-related floods, droughts, water scarcity and food insecurity.

More than one quarter of the world's population, approximately 2 billion people, do not have regular access to nutritious and sufficient food and the Covid-19 pandemic only makes matters worse. The painful irony is industrial agricultural systems with high greenhouse gas emissions, such as we have in Ireland, contribute to climate change and biodiversity loss. We must get our house in order. The best thing we could do to prevent increases in global hunger and malnutrition and to avoid future breakdowns in food and livelihood systems is to ensure our agrifood policy and processing of food do not contribute further to climate change.

On the issue of biogenic methane, action 4 states that "Biogenic methane such as methane from ruminant livestock is different from other greenhouse gases because of its biological origin and its relatively short life span in the atmosphere." That statement is quite misleading. Biogenic methane and methane are the same molecule, as the witnesses are aware. They are the same thing and have the same effect in terms of global warming potential, irrespective of their source. The biogenic refers to the source. It is misleading because it implies this methane has a different effect on global warming potential when it does not. It does not have a shorter lifespan than fossil-derived methane in the atmosphere, regardless of whether its source is biogenic. Methane, whatever its source, needs to be reduced drastically if we are to tackle climate change.

The point below that on the Teagasc submission refers to the GWP100 and the GWP* systems of accounting but GWP10 and GWP20 were not mentioned. If GWP10 and GWP20 had been mentioned, one would have stated methane had a global warming potential of 88 times the warming effect with those systems as with GWP100. It is short-lived compared with carbon dioxide but converts to carbon dioxide after it breaks down. It is a potent greenhouse gas and is not, by any means, an insignificant one. No matter what system we use, we cannot get away from that.

I ask the witnesses to give us more information on the most important line in the statement, that reducing methane "can be associated with a cooling effect". That is critical. On the issue of biogenic methane, the statement notes that "the CO2 produced is effectively new carbon released from permanent carbon stores and therefore must be treated differently because it inputs additional CO2 into the atmosphere".

The reality, however, is that increasing herd numbers inputs additional CO2 into the atmosphere also. I think there is a sleight of hand here. This line gives the impression that methane that comes from ruminants is somewhat less harmful than fossil-derived methane, and that, scientifically, is not correct. Teagasc goes on, on the last page of its submission: "Because of the significant difference between biogenic methane and fossil fuel derived CO2, scientists propose setting a separate target for biogenic methane in climate targets." That is the subject of debate, but I do not believe - and the witnesses may correct me if they know more about this - that the IPCC or the United Nations have proposed any change in how we account for biogenic methane.

I will ask the witnesses some questions. I know we do not have much time, but if they would like to revert in writing, I would appreciate that. Can they tell me how much the beef and dairy herd have grown in numbers in the past five to ten years and what the increase in nitrogen fertiliser has been over that time? That, of course, is a very significant greenhouse gas with a global warming potential of, I think, over 200 times that of CO2. In Teagasc's 2020-27 sectoral roadmap, it shows projected increases in cattle numbers from 1.4 million to 1.65 million and increasing output from the dairy sector. Could the witnesses give us an indication of the expected overall emissions increase from the beef and dairy sector attributed to 2027, not on an efficiency-per-cow basis but from an absolute emissions point of view? I do not expect them to have these numbers right now, but if they could revert, I would appreciate that.

As for the issue of hedgerows, the document Teagasc sent us refers to sequestration from hedgerows, and we know hedgerows are excellent for biodiversity and should be promoted. I wonder how impactful they are from a carbon sequestration point of view. Perhaps the witnesses could estimate the numbers quoted in their note to us to give us the national picture. How much hedgerow coverage have we got in Ireland, and what is the suggested coverage of hedgerows over the next few years? I think Dr. O'Mara said we have 650,000 km of hedgerow, but how does that translate into an acreage basis? I think it was Dr. O'Mara who mentioned that 50% of methane emissions can be offset by sequestration on the average suckler farm. Is that a temporary or a permanent sequestration? How is it verified, and is there a scientific basis that is aligned with the EPA's methods for compiling its emissions inventory?