Professor Barry McMullin:

I will try to be very brief. The questions were very well put. With regard to the legal provision in the Act and the 51%, as members of the committee will be aware, it is on the record that Professor Sweeney, Professor Jackson and I wrote to the Government of the time suggesting that the way this was framed in the Act was unsound and should be revised in certain ways which we suggested. In that Government's wisdom, it decided not to accept our suggestion. The way it was put into the Act was unfortunate and caused unnecessary difficulties for the council. I sympathise with it on how it had to try to deal with those difficulties. I cannot speak on behalf of the council and I am not sure of the nature of its discussions on this matter but it is possible that this provision had the effect of limiting the scale of ambition the council could consider over the ten years to 2030. As I have said, I do not know whether that was the case but, because of the poor legal language of that particular section of the Act, that is a possibility.

However, it is important for the committee to be aware that it is not bound by that legally. That provision in the Act applied only to the council. The process the committee is now engaged in is quite separate from that. It is not bound by that provision in any way, shape or form. As I said in my submission, at a minimum, the committee should consider a further reduction in the budgets proposed by the council to align with the original programme for Government. This would represent a reduction of approximately 27 Mt CO2 eq across the two periods. I recommend that the committee take aviation into account. It is unclear why the council left that out. That would take away another 40 Mt or so. In round numbers, that would bring it back to something like 400 Mt CO2 eq over the ten years.

Deputy O'Rourke rightly queries why that figure is so different from that suggested by Professor Anderson, because my position is very different. It is a much bigger number than the numbers he has suggested. It must be remembered that Professor Anderson's budget is not for up to 2030, but forever. There is a discrepancy there but it is only an apparent discrepancy. It primarily reflects the fact that Professor Anderson is presenting a budget exclusively for carbon dioxide whereas the budget I am talking about, the 400 Mt to 2030, is for the big three gases: carbon dioxide, nitrous oxide and methane. A relatively large proportion of Ireland's emissions are in the form of methane and nitrous oxide, which skews matters. For other countries, that discrepancy would not be so big. It makes it appear much bigger in Ireland. I will refer to something that will really only come into play as we move to the sectoral emissions ceilings part of the debate. I have suggested a budget of 400 Mt to 2030, as opposed to the 490 Mt the council has suggested.

Whether even that is adequate or consistent with the Paris Agreement temperature goals still hinges on how it is broken down by gas. If, for example, there is comparatively little reduction in methane by 2030, say 10% or 15%, and there is more of a reduction in nitrous oxide and CO2, that would not be enough. It would still exceed what would be prudent. The science is complex, and I apologise for that, but the discrepancies hinge on the things the council omitted, including the way it treated historical responsibility and aviation emissions, the constraints on reflecting the full force of the programme for Government targets and the way the Act was framed. Certain discrepancies arise on that basis. The interactions between the different gases give rise to a superficial discrepancy, though it is only a superficial discrepancy. If we make deep reductions in methane emissions, that would resolve those discrepancies.