Professor Barry McMullin:

I thank Deputy Whitmore. It is a tricky issue because, as she says, the addressing of international aviation and shipping emissions has been fudged for a long time in international negotiations. Regarding the link in the submission, the advice from a very eminent legal expert is that the Paris Agreement does not include any such exception. With regard to binding the parties, or parties binding themselves, to pursuing the temperature objective of the Paris Agreement, aviation emissions must be taken into account. There is no other competent authority in the Paris Agreement; the parties are the countries. Therefore, given that the physical emissions from international aviation and shipping absolutely affect the climate, the only people under the Paris Agreement who can address that are the parties to it, and therefore they must do so. It is up to the parties – this is the bottom-up nature of the Paris Agreement – to figure out how to do that. That includes doing so domestically in Ireland and at European level.

The domestic Irish legislation, namely, the climate Act 2021, somewhat fudges this in the sense that the budgets exclude international aviation emissions but the setting of the budget is a separate matter. That is what we are talking about today. In the setting of the budgets, you have to look at Ireland’s contribution in respect of warming relative to what is required at a global level. Ireland’s contribution to international aviation and shipping is certainly contributing to the heating, so in setting the budgets you need to make an allowance for that. It effectively means that the budgets for domestic emissions need to be smaller to leave provision for whatever we are doing in terms of international aviation and shipping. However, the council has not addressed that in its test of whether domestic budgets, exclusive of aviation, are sufficiently in line with our global obligations.

It would not be enough, of course, even if the budgets were set in an appropriate way. They would be smaller as a result. The question of how much smaller depends on how much emissions you are going to have in international aviation and shipping. As the budgets are already extremely challenging, you do not want to reduce them any more than you have to. The logic of that, however, is that you have to look at what is happening under international aviation and shipping. Everybody is agreed that if the passenger cap at Dublin Airport, mentioned by the Deputy, is lifted, emissions from international aviation will go up by a significant amount. The passenger cap is not necessarily a good or appropriate way of seeking to limit emissions from aviation. It was not put in place for that reason. Nonetheless, if it is removed, emissions will go up. To me, the logic of that is that is that if the passenger cap is to be lifted, some other kind of measures or policies will need to be adopted to constrain and ideally reduce over time the emissions from international aviation and shipping. That is extremely difficult, particularly for aviation, whatever about shipping, where some technological options are viable. In aviation, yes, we can make aircraft a little more efficient. There is the idea of sustainable aviation fuel, but it is available only in tiny quantities and is highly unlikely to be available, in quantities comparable to what we currently use, within the next 20 years. This is the critical time for constraining emissions. It opens up a much wider discussion than the budgets alone but, in our view, it absolutely needs to be discussed and addressed at the same time. You do not just remove a constraint and then let things happen as they happen. You plan ahead and ask what the impact will be on emissions and what other things we need to do to manage this.