Transport Committee
Oral evidence: Scrutiny of the draft Heathrow Expansion National Policy Statement, HC 482
Tuesday 8 September 2026
Ordered by the House of Commons to be published on 8 September 2026.
Transport Committee members present: Ruth Cadbury (Chair); Steff Aquarone; Dr Scott Arthur; Jacob Collier; Daniel Francis; Olly Glover; Alex Mayer.
Environmental Audit Committee member present: Barry Gardiner.
Questions 112–139
Witnesses
I: Celeste Hicks, Policy Manager, Aviation Environment Federation, Dr Lois Pennington, Research Associate, Tyndall Centre for Climate Change Research, University of Manchester, and Alethea Warrington, Head of Aviation, Energy and Heat, Possible.
Written evidence from witnesses:
– Aviation Environment Federation
– Possible
Witnesses: Celeste Hicks, Dr Lois Pennington and Alethea Warrington.
Q112 Chair: Welcome to this afternoon’s session, the second in our scrutiny of the Government’s draft Heathrow expansion national policy statement. I welcome Barry Gardiner, who is joining us again as a guest from the Environmental Audit Committee. We are hosting two panels this afternoon. In our first panel, we will hear about climate change and carbon emissions. In our second panel, which will start at about 5 o’clock, we will question academic experts about air quality and the noise impacts to be considered. Will our first panel of witnesses please introduce themselves? I apologise that you are so far away, but this is the only room we could get.
Celeste Hicks: Hi. I am Celeste Hicks. I am policy manager at the Aviation Environment Federation.
Dr Pennington: Hi. I am Lois Pennington. I am a research associate based at the Tyndall Centre for Climate Change Research at the University of Manchester.
Alethea Warrington: Hi. I am Alethea Warrington. I am head of aviation, heat and energy at Possible, which is a climate charity.
Q113 Chair: Welcome. We have quite tight timing today, so if you could, keep your answers as brief as you can. You are welcome to send us additional data or information afterwards.
From the point at which the Government announced their support for Heathrow expansion early last year, they emphasised that any scheme will be required to align with legislated carbon budgets and net zero targets. Would passing the climate test as expressed in the draft HENPS demonstrate that the Heathrow expansion scheme is genuinely compatible with net zero targets?
Celeste Hicks: Thank you for the opportunity to talk to you all and thank you for holding this inquiry. We at AEF think that the carbon test is inadequate. It is a bit complicated to explain why, so bear with me—I will try my best. Basically, the climate test says that the project should not materially impact the ability to meet carbon budgets. So far, so good, but the problem is that carbon budgets cover the whole economy. To explain—you probably all know this, so forgive me—it is like a big bucket: you can keep putting emissions in until they overflow. The idea is that you level that out across the whole economy.
The problem is that we are looking at one specific project. Therefore, when we look at how that is decided—whether the project has that material impact—first, the HENPS documents do not tell us what a material impact is and, secondly, the decision about whether the economy-wide carbon budgets are met is made by DESNZ, not by the DFT. What would happen is that DESNZ goes to the DFT to ask, “What is your sectoral pathway for emissions reduction?”, and the DESNZ Secretary of State then decides, “Okay, this is compatible with the economy-wide emissions reductions.”
The problem is that the DFT’s decarbonisation strategy, which this decision relies on, is jet zero, but buried in the aviation forecasts that came out alongside the HENPS, it was basically admitted that the jet zero strategy was failing. You can look at the different scenarios yourselves, but the central scenario of jet zero said that residual emissions would be 37 megatonnes by 2050; the HENPS forecast says 41 megatonnes, which is a more than 4 megatonne difference, so jet zero is not delivering.
The problem is that no one has responsibility for that, and certainly not Heathrow. When Heathrow puts in its DCO application, all it needs to say is, “Well, jet zero will deliver the national emissions reductions that we need.” It does not have to show any emissions reductions from its own operations, apart from with things like surface access and auxiliary power units. The national aviation budget is dealt with by the jet zero strategy, which is failing—but the DFT does not decide the national budget; DESNZ decides it. Basically, that is how this is explained and tested, and we do not think that that is good enough.
If we look at what has happened in jet zero, some of the SAF projections and the greenhouse gas removals are well below what we thought they would be. I know Lois has lots to say, so I might hand over to her to explain that, but basically they have left that out and said, “Well, what we’ll do is we’ll make sure that the terminal capacity won’t come online until later on in the carbon budget.” Even though the runway will have been built, the DFT modelling says it will not fill up because the terminals will not have been developed. That will happen around 2038 to 2049, and in 2050 we do not have any carbon budgets any more. They have also talked about displacement, but it is probably better if Lois explains the idea behind displacement. Basically, they are saying that the jet zero strategy will not deliver the emissions they need, so they have tried to look for another way to do that. I hope that made sense.
Chair: Thank you. That was very helpful. Over to Lois.
Dr Pennington: Just to underline that, my reading of it as well is that as the carbon test is drafted, it will not be compatible with net zero. Material impact is not defined, so it is impossible to read that and to understand whether a particular infrastructure project would or would not fail—it is subjective, in a way. As Celeste said, that is measured against the whole-economy carbon budget. Recently, we released a report on the effect of Heathrow expansion on our ability to meet carbon budget 7, which covers the period 2038 to 2042, which is the first legislated carbon budget that Heathrow will have a major impact on. That budget for the whole economy is around 535 megatonnes—that is for every single sector in the whole UK. The aviation subsector budget recommended by the CCC is around 146 megatonnes. It is still a high percentage—it is nearly 30%—but of course any infrastructure project would be a larger percentage of that. The aviation sub-budget would be the correct thing to test against. Currently, you cannot tell whether it would pass or fail.
Just to touch a little on the displacement element that Celeste mentioned, the aviation forecast for 2026, which has just been released, assumes that the third runway at Heathrow will, to begin with, take around 75% of its traffic from other local airports—Gatwick, Luton and City. Of course, they have also just had expansions approved, so they would have those expansions approved but then lose that traffic to Heathrow. That means that when you look at the net total increase in aviation in the UK, it actually does not look that high, because you are just moving aviation from one airport to another. However, that enables, in future—this is included in the modelling—the new capacity at Gatwick to refill, and Heathrow to fill up the runway with net new flights. If you look beyond the legislated carbon budgets—beyond 2042—the impact is significantly higher. However, it is very difficult to compare that, because right now we do not have a legal carbon budget to compare it to.
Alethea Warrington: We also think the test is just far too weak. It is drafted in such a way that it seems to comply with the UK’s legal requirements to meet carbon budgets, but actually there are no teeth in the HENPS, and there are also no thresholds. There is nothing in there that gives the airport any kind of maximum emissions barrier that, if breached, would cause the Secretary of State to say no to the expansion. There is no minimum viable requirement or plan for it to mitigate its emissions.
The HENPS explicitly sets out that the emissions from the third runway will be addressed economy-wide, so that is essentially a huge “get out of jail free” card for the airport. To the extent that there are actual requirements on climate in the HENPS that are levied on the applicant, they are very vague and unquantified. They are like “support SAF” and “invest in decarbonisation technologies”. There is no sense at all of how much investment there has to be, whether any of the investment has to have any measurable impact on the total emissions, or at what threshold of unmitigated emissions the Secretary of State would be obligated to say no to the applicant.
There are also a lot of gaps in what is covered by the HENPS. There is nothing on even quantifying the non-CO2 emissions. That is basically two thirds of the warming impact from the airport that basically just being completely ignored.
The underlying problem with the HENPS is that it is based on the jet zero strategy, which assumes that it is fine for the aviation sector to just hugely expand and that technology will come along and deal with it. There is no requirement at all on the sector as a whole, or any actor within it—any airport that is seeking expansion—to have demonstrated that these technologies are deliverable and affordable and can be resourced within the rest of the economy before expansion is permitted.
Chair: Thank you. Those were very full answers and may have covered answers to some of our other questions.
Q114 Dr Arthur: I think that has largely covered what I was going to ask. I was going to ask whether the climate test was a tick-box exercise. Playing devil’s advocate, though, if the development can fit within a carbon budget that works, and can fit within the jet zero strategy, which was working, surely that is good enough?
Celeste Hicks: Technically, yes, but—
Dr Arthur: Well, that’s okay, then!
Celeste Hicks: Our perspective is that we should have a discussion, as an economy and a society, about what activities we think should be allowed to consume that ever-shrinking amount of carbon. If we are going to stick to our climate targets, we have to do that. If you look at what is happening in other sectors that are decarbonising, I can imagine they will be quite annoyed that aviation has basically been given, as was said, a “get out of jail free” card to keep expanding while other sectors are having to reduce.
It will mean that we have to speed up the roll-out of heat pumps and electric vehicles, electric blast furnaces, and other things in other parts of the economy. We at AEF think that we need a discussion as society about whether we want to grant those remaining, residual emissions to one sector that is, in many ways, a luxury sector with a lot of leisure travel. Maybe if people understood the nature of the carbon budgets, it would be technically, feasibly, mathematically possible, but the moral case is possibly not as strong.
Q115 Dr Arthur: I was going to ask what you think the test should be. I do not want to put words in your mouth, but you seem to be saying that we should be looking at all these big carbon uses and developing some kind of hierarchy. Maybe it will be that blast furnaces are easier to decarbonise than an expanded Heathrow, but we don’t know that yet. Well, let’s not put words in your mouth. What should the test be?
Celeste Hicks: What we are doing here is assuming that the blast furnaces and other things will have to be done first. I do not think we have had a discussion about that. If you look at what we were trying to say about how complicated it all is, at the moment the test appears to be meeting carbon budget 7, which is the only one we have legislated for. It is not meeting carbon budget 8, because we have not legislated for that yet, and it is not meeting anything after 2050. If you stick only with the very narrow definition of the carbon budgets, you miss huge amounts of the carbon impact of the test.
I think it needs to be showing that there is a demonstrable reduction in aviation emissions happening across the board before it is given the go-ahead. That isn’t something that is pie in the sky, because if you believe the aviation industry, things like SAF and greenhouse gas removal are going to deliver, and zero emission aviation is going to come online. We are not going to say that isn’t true. It may well be true in the future, but the problem is that if you let that happen now, it is a risk, and I think it is a society-level decision to let that risk. We would want to see measurable targets of reductions in emissions before it goes ahead.
Dr Arthur: I am guessing the other two witnesses would broadly agree—okay. It sounds like we need blast furnace people before the Committee, Chair, so we can really explore this.
Chair: Yes. Obviously, these debates are true whenever we talk about carbon budgets and net zero by 2050, which seems to be rapidly coming towards us.
Q116 Steff Aquarone: You have answered quite a few of the questions on carbon budgets and emissions projections, but I wonder if I could ask a specific question about the Climate Change Committee’s estimates. The Department for Transport’s own emissions forecasts are quite a lot higher than the CCC says they need to be. Specifically on the reductions required or the technology used, do you have any comments on what that says to us about the Department for Transport’s views on what the Climate Change Committee has perhaps assumed—or maybe they know something we don’t—about technology advances that are to come?
Alethea Warrington: The CCC’s projections on the scale of technological developments, and consequently the space within the emissions budget for aviation expansion, is much more realistic than the Department for Transport’s. The CCC’s assumptions are also in some ways quite generous, but even with quite optimistic assumptions about technology, the CCC is really clear that there is just no space at all for net aviation expansion, at least into the medium term.
The DFT just seems to assume that you will have this absolutely massive, unprecedented scale-up of these very expensive, very resource-intensive technologies; that SAF will be delivered at an unprecedented scale. On the resource requirements for that alone, the Royal Society report found it would need 68% of the UK’s agricultural land. That is completely ridiculous. The impact on food prices, the whole economy and the cost of living would be completely ridiculous.
It is also a huge problem that DFT does not have any costed or resourced plan to deliver the carbon removals that underlie the whole jet zero strategy. It does not have anything approaching a plan to mitigate the non-CO2 impacts, so that is two thirds of warming unaddressed. The DFT really has it the wrong way round. They just assume that aviation has to grow and aviation can grow, and that technology will come along to deliver it and somehow, across the economy, that will be dealt with. It is just a completely un-evidence-based approach.
Q117 Steff Aquarone: Maybe they think we will eat a lot more chips than we currently are, or something like that. Any other comments on that?
Dr Pennington: One thing I wanted to say at the beginning of this session is that the DFT has released its aviation forecasts, which include emissions forecasts, and as part of the work we did for this report we looked at which of those were actually within our seventh carbon budget. Even before Heathrow expansion, every single scenario took us well over what aviation’s share is. That has to be a key framing when we are talking about this: Heathrow is not expanding in a world that has room to expand; it is expanding in a world where we are already significantly over. In the central case the DFT put forward, which is current trends for behaviour and flying, even in the best-case scenario, where sustainable aviation fuel meets the mandate that has been put in place—there are serious questions about whether that technology will arrive at the scale and pace that we need—it was still 30 megatonnes over the budget. That is the equivalent of taking something like one in 10 cars off the road for five years—it is a really high amount. I just wanted to make it clear that that is what we are talking about.
Celeste Hicks: I know you are concerned about environmental mitigations, so I will add quickly that there is nothing in the HENPS document that makes sure that any of this stuff is actually delivered. We talked about the displacement; that is a modelling assumption. We talked about the terminal capacity being small, so that even if the third runway is built, it will not fill up immediately because the terminal is not available; that is also an assumption. None of it is written into the HENPS to say, “This has to happen.” The only way that they could get it to look like the emissions impact would not happen until later was to have these modelling assumptions, and there is nothing in it to say that they have to happen.
Q118 Chair: Let us turn to non-carbon emissions. Aviation, I think more than any other sector, produces emissions beyond the carbon emissions that have significant climate impacts. The draft HENPS says that applicants will have to provide only a qualitative assessment of the impact of non-carbon dioxide emissions, not a quantitative one. Do you agree with the reasoning behind that? If they are not required to quantify the non-CO2 emissions, to what extent can the climate impacts of expansion be accounted for?
Alethea Warrington: It is a serious flaw in the HENPS that it does not require the non-CO2 impacts to be quantified. Again, that is echoed in the jet zero strategy, which also fails to do that. The DFT’s reasoning seems to be that there is too much scientific uncertainty, but that is just ridiculous. There is very clear scientific consensus that the non-CO2 impacts of aviation are two thirds of the total, so two times the carbon impacts.
The even bigger underlying problem is that there is not really any effective mitigation pathway for those non-CO2 impacts. Even if the SAF is delivered as planned, even if you get 19 million tonnes of carbon removals coming online by 2050, and the cost, resources and all that work, you are still mitigating only around a third of the impacts. It is such a huge problem. The DFT says it is too uncertain. It is not uncertain, but even if it was, the precautionary principle suggests that they should take that more seriously, not just ignore it.
Q119 Chair: In terms of the changes you would make, do you all believe that those quantifiable measures are there and could be inserted?
Alethea Warrington: They definitely should be, and that should go along with some kind of plan to mitigate those measures.
Celeste Hicks: DESNZ has a published recommended multiplier of 1.9 times. There is a bit of debate about whether it is 1.9 or 2, but DESNZ has a figure, which is used when it is doing other assessments. When companies are reporting their corporate emissions under SBTI targets, they use the multiplier to show the impact of non-CO2 emissions. It does not make any sense to us that another Government Department says that you can quantify this, but that has not been used at all, even to assess it. As Ali said, they are not even assessing it, let alone mitigating it. This is a problem.
Things will change. As you know, in the EU they are now monitoring contrails, and there is an MRV going on at the moment. The science is coming all the time, and it is likely that that will develop into some kind of policy in the future, but again, there is nothing in the HENPS that says that you have to take account of that, even if the science does become clearer—and we agree that the science is clear enough. We do not see the reason for than when you have another Government Department that publishes a figure.
Q120 Barry Gardiner: Ms Warrington, I am not clear about the figures for SAF that you quoted. I thought that CB7’s balanced pathway said that 38% of liquid fuels would be SAF by 2050, meaning that the majority of flights from an expanded Heathrow would still be running on fossil fuel after 2050. I think you used a figure that suggested that the majority would be running on SAF, but that is not the case, is it?
Alethea Warrington: I was referring to the jet zero strategy, and I think the DFT has more optimistic assumptions about the level of SAF deployment, but I definitely agree that even the slightly lower levels that the CCC suggests are reasonable are still incredibly optimistic. That is still a really high level of SAF to get.
Q121 Barry Gardiner: Just for clarity, I was quoting the Committee on Climate Change’s figures and you were quoting the Department’s figures.
Alethea Warrington: Yes.
Chair: Thank you; that is helpful. We will now go back to net zero policies and economics.
Q122 Jacob Collier: As you have recognised, aviation is a huge contributor to our carbon emissions. How do you think zero emission flying technologies, airspace modernisation and improved aircraft efficiency will help to deliver the emissions reductions required to support Heathrow expansion, if at all?
Alethea Warrington: I think they will have a relatively minimal impact. Zero emission propulsion technologies—hydrogen and electric planes—are going to be incredibly difficult. Even the Department for Transport, which is very techno-optimistic, recognises that the proportion of emissions reductions by 2050 will be just a few per cent. They are very, very far away.
The DFT relies more on efficiencies but, again, there are marginal gains at this point. Jet engines are already very efficient. The industry is already financially incentivised to optimise for efficiency. The Government talk a lot about airspace modernisation, but a key goal of that is to get more planes into the sky. I think the emissions reductions from all of those will be relatively minimal.
Dr Pennington: Since the jet zero strategy came out, the Department has reduced its level of optimism. Zero emission aircraft are assumed not to arrive at all within the periods that have been forecasted, whereas in the jet zero strategy in 2022, they were assumed to come online sometime in the 2030s. Similarly, the efficiency assumptions have also been downgraded by the Department, even in the four years since the jet zero strategy. The evidence is showing that we cannot rely on these technologies to arrive at the pace and scale that we need.
Celeste Hicks: You only need to look at the aviation forecasts to see that the Government have had to go back and start remodelling that. They have already announced that they will be redoing the jet zero strategy in early 2027. We have quite a big problem with that, because Parliament has been asked to decide whether this HENPS is adequate before that remodelling has been done. It has just been announced in the aviation forecast that it is falling behind schedule. I can only imagine that that situation might not get better by next year, by which point it has been baked into the HENPS that we can go ahead with this thing. That is a real problem for us. You really have to go into the modelling of it, but there are some quite significant changes on airspace modernisation and efficiency gains that will be remodelled.
Q123 Jacob Collier: We have touched on sustainable aviation fuels. How important are those to the case that Heathrow expansion will meet climate targets?
Dr Pennington: As I said, if we are talking about a sector that is already massively over its budget, the question about sustainable aviation fuel is, how much can it limit the damage? Even if SAF arrives at the mandate level within the carbon budget 7 period, we are still expecting it to bring us tens of megatonnes over the budget. The only scenario we modelled that kept us within our carbon budget was if SAF arrives at the mandate level, but demand is held completely flat from this point onwards and does not increase. If SAF does not arrive, our emissions will go over our budget. It is critical, but we cannot rely on it.
Ali mentioned the precautionary approach. If we look at the SAF plants that have been funded and the SAF plants that have been built, and bearing in mind that every single economy around the world is now looking to use SAF because they want to decarbonise their own aviation, we cannot rely on importing it from anywhere. The amount of SAF that is forecast to be produced in the UK does not look very promising after about 2030. I can follow up with the exact figures.
Alethea Warrington: The fundamental problem is that there is a very limited amount of alternative feedstocks available. There is not a huge alternative source on the scale of the aviation industry’s demand for kerosene. There is not the available agricultural land, the available waste or the available biomass. The more the aviation industry tries to take from other sources, the more we will potentially see problems elsewhere. We are already seeing that the sector is trying to lobby to reduce the sustainability requirements so that it could use fuels from crops. If they try to scale that up, it could have a gigantic impact on food security and deforestation, so there needs to be a lot of caution about SAF.
Q124 Jacob Collier: I guess from what you say that you don’t believe the UK is going to meet its SAF mandate.
Alethea Warrington: It is already not meeting it at a very small scale. There is no sign that it will find it easier to deliver at a larger scale.
Celeste Hicks: We were quite surprised that the importance of SAF was not drawn out as much as we thought it would be. When the Heathrow expansion plan was unveiled in January 2025, it was assumed that SAF would be the golden bullet. We have discussed this internally, and we think one of the reasons is because the DFT have looked at the figures and said, “Not quite sure we’re going to get there.”
If you look again at the aviation forecasts—I am sorry; I spent the summer looking through thousands of pages of tables and spreadsheets, so I just need to get this off my chest—the SAF assumptions have dropped from 50% in 2050 to 30% in 2050. We think that SAF is maybe not playing the role that we thought it would because they are looking at the numbers and it does not make sense.
We are not quite sure what happens post 2030. Things look okay now on delivery, but that is because it is mostly HEFA SAF. For example, I think Heathrow attracts some 17%, or even more than that, of the world’s global SAF supply. That is coming to Heathrow at the moment because they are paying huge incentives for airlines to uplift SAF from Heathrow but, obviously, that will change. As people have mentioned, other economies are doing that.
Beyond 2030, we really don’t know. The Government is doing some great work on the revenue certainty mechanism, trying to encourage second-generation fuel producers to build plants in this country. They are small scale, but they will make a difference. But we are behind schedule with that as well: we were expecting contracts to come this year, and it looks like they will not come till the end of 2028. You can see already that we are getting a couple of years behind where we need to be. I think that is why the assumptions have been revised down.
Chair: Do you want to come in, Barry?
Barry Gardiner: Very briefly.
Chair: For the record, Barry is from the Environmental Audit Committee, which produced a very extensive report last year—or was it earlier this year?—on aviation and the environmental impacts.
Q125 Barry Gardiner: Dr Pennington, I believe you were the lead author on the Tyndall Centre’s report. In that you spoke about the infrastructure for large-scale SAF production and how greenhouse gas removals should be operational prior to the infrastructure to expand the aviation sector. Is one of your main beefs with the HENPS that they have put the cart before the horse? That is fine if you can show you are going to do it, but don’t assume you are until you actually have the infrastructure in place to do it.
Dr Pennington: Yes. Beef, I suppose, is the word. Yes, that is the main point that we wanted to get across. I started working in this sector in 2020. I remember writing a review of all of the plants that were meant to come online by the time I had finished my PhD, and now it is six years later and none of them has. They have been delayed and closed around Europe, or the websites have gone dark. Again, based on the precautionary approach, we should make sure that we have the technology in place ready to operate before we even consider expanding. That was in the CCC’s advice on the sixth carbon budget—that we should not expand our aviation infrastructure until the sector is well ahead of its carbon targets, which we can say it is categorically not. It is behind.
Q126 Alex Mayer: You have already expressed a degree of scepticism about greenhouse gas removals. What level of them would be needed to compensate for a third runway at Heathrow?
Dr Pennington: I keep going back to the same point, but again, there is a slightly different question, because we are already projected to be over. We would already need additional removals to compensate for how much it is going over before the third runway, and then on top of that as well. When we talk about the carbon budgets, it is worth bearing in mind that at least when you look at carbon budget 7, they already have the removals baked in. Aviation’s sub-budget of around 146 megatonnes already relies on there being around 21 megatonnes of carbon removals throughout the period, 60% of which goes to aviation. A really large share of that is going to remove aviation’s so-called residual emissions.
At the moment, the global capacity for greenhouse gas removals is only 2 megatonnes per year in the whole world. Getting from that to 21 megatonnes just to meet carbon budget 7, plus whatever else we go over in the aviation sector—30 or 40 megatonnes—is just an astronomical amount.
Celeste Hicks: The simple answer is that it would be effectively 41 megatonnes, because when you get to 2050 and you have 41 megatonnes of unabated emissions, we have nothing other than greenhouse gas removals to address those residual emissions. The difficulty in understanding the impact of Heathrow is in what we were saying about how the carbon budgets are measured, and because greenhouse gas removals are not accounted for under the aviation sector, so it starts to get a little complicated. We estimated that it is around 3.5 megatonnes extra per year from the Heathrow runway from 2050 onwards, so you have 41 megatonnes, possibly plus 3.5 megatonnes, depending on how you look at the modelling. Anyway, it is a big number, as Lois said, compared with what we have today.
Alethea Warrington: It is worth adding that there is no plan for DFT on how that will be delivered, who will pay for it, what the technologies will be, the resource impact or the electricity requirements. There is currently one plant in the world doing even remotely large-scale carbon removals, and that is in a very specific location where it has access to geothermal power and underground storage. The idea that we could replicate that at the scale needed for this one sector—for this one airport—seems very based in fantasy, really.
Q127 Dr Arthur: Are carbon pricing and emissions trading part of the solution?
Celeste Hicks: Well, yes—
Dr Arthur: Ah! I found it.
Celeste Hicks: Can it be the solution? Again, going back to the aviation forecasts, one thing the eagle-eyed among you will have noticed is that the carbon price used under the jet zero high-ambition scenario was—I will just check my figures here—£432 per tonne. One of the reasons why the emissions have shot up under the jet zero scenario is that DESNZ has now come up with a much more reliable way of calculating what the emissions trading price will be in the future.
Previously, jet zero said it needs to be £432 per tonne, and that is how we will get to 19 megatonnes in our high-ambition scenario. DESNZ now says that it will be more like £125 per tonne, which is why the emissions have shot up so much. It is about £40 a tonne today, so there is still quite a long way to go until it actually reaches that level. The other thing is that there is no mechanism to ensure that the carbon price rises to meet what we need it to do—in effect, dampen demand by making it more expensive to fly. There is no mechanism at all available for that.
The other problem with emissions trading is that only about 25% of flights at the moment are facing a carbon price, because it covers flights only between the EU and the UK at the moment. The EU is trying to extend it, just marginally, but is avoiding going to America so that the Americans do not get angry about carbon pricing and taxing. Basically, 75% of the emissions are long haul, and they are not being priced.
On top of that, the long-haul flights are the ones more likely to create contrails, and we have also missed out the contrail warming impact. The ETS could have much more potential if the price was higher and there was a mechanism of guaranteeing a higher price, but there isn’t—sorry.
Dr Pennington: Carbon pricing is not our area, but price signals have not historically had much impact on demand itself. When you look at the group of people who are flying the most, 50% of flights are taken by the highest earning 10% of society. Those frequent flyers are not the people who would necessarily be put off by higher prices.
Alethea Warrington: It is quite a blunt mechanism. It definitely has a role to play, and it needs to go up, but it does not necessarily seem fair that the cost of a tonne of carbon emitted by someone taking their first flight in two years is the same as the cost of a tonne of carbon emitted by a millionaire flying on a private jet. You would also want to make sure that it does not have a distorting effect across the economy. We need a much higher carbon price for aviation emissions, but you would not want that to, for example, make food or people’s daily essentials more expensive.
Q128 Dr Arthur: Someone in the Government said that we all have a right to go on holiday in the summertime. That is an interesting perspective given the wealth inequalities that you are talking about. Is the projected carbon price not incentive enough for change, in terms of trying to change the emissions profile? The numbers are moving around a little bit.
Celeste Hicks: Last time, when we had the ANPS in 2018, they used indicative carbon modelling prices, which honestly blew my mind because either it costs a thing or it does not cost a thing. Apparently, it was just an assumed value that DESNZ used to appraise what the price of the carbon would be to keep the demand at a level where it would not exceed the carbon budget. Since then, there have been big developments at DESNZ in terms of working out what the carbon price is actually going to be as opposed to what it should be.
In the last round of jet zero, in the high-ambition scenario, they had to crank the carbon price up to £432 a tonne to keep the demand at the level they needed so that it met the trajectory. I am sure we will talk about demand management, but—you might remember I said this at the Environmental Audit Committee—carbon pricing is a form of demand management. Basically, you increase the cost of flying so that you reduce the amount of people who can afford to fly.
Obviously, if it is just a number you can stick in a spreadsheet, you can put anything in there. When you actually start thinking, “What does that £125 mean on your average family summer holiday ticket and what now does DESNZ think the price will be?”, it starts to be more real. Again, if you need £432 to deliver 19 megatonnes of residual emissions, and it is actually going to cost almost a quarter of that, you are not going to have the same dampening of demand. It is really complicated; this is the trauma of it.
Q129 Dr Arthur: On the point you are making about demand management, I was thinking, “Well, is this still really meeting the climate targets if all they are doing is buying these credits?” But you are saying it could reduce the demand to use Heathrow and therefore reduce emissions. Then the question is, why are we upgrading the airport only to throttle the demand because of emissions?
Celeste Hicks: You have just had a “Eureka!” moment.
Dr Arthur: Thank you—you facilitated it!
Celeste Hicks: Lois can probably answer this better than me, but that is broadly what the Climate Change Committee said in its advice last time round. So it said instead of demand management being through capacity constraint, which is basically what we currently have at Heathrow—demand is not exploding everywhere because it is constrained—we will stop doing that because we do not want to say that you cannot expand airports, and we will say that carbon pricing is effectively the demand management, but we will call it carbon pricing; we are not calling it demand management. Lois probably has plenty to say on that.
Dr Pennington: No, that was it. In their modelling, the CCC have used an assumption that it will become too expensive to fly because the aviation industry is bearing the cost of decarbonisation, whether through technologies or carbon pricing.
Chair: And the airlines will say they are also having to bear the capital cost of the infrastructure, so there are two sets of potential costs. If they are passed on to passengers, which came into some of the modelling, they will reduce the demand such that we might ask whether there is a need for a third runway.
Q130 Barry Gardiner: Is that not then regressive? Instead of the demand being a constraint on the flights going out at a lower price, you are bumping up the price in order to get the same level of constraints. That means that the poorer people will be cut out of their family holiday, whereas the wealthier people will not. It is actually a regressive way of doing it.
Celeste Hicks: Yes.
Dr Pennington: Yes.
Q131 Chair: While we are on this topic, some organisations have advocated for frequent flyer levies as a more progressive form of demand management, because the bulk of Brits who fly at all go once a year, and a small proportion—15% of British people—generate 70% of passenger demand. To what extend could a frequent flyer levy play a part in demand management in this context?
Alethea Warrington: The problems with the technological solutions are really severe. It is not just that they are not working yet; they are never going to work at the scale needed. That means that demand management has to play a role. In order for this to be fair and acceptable to the public, it has to take into account how incredibly unequal access to flying is. As you say, most people fly rarely, if at all, and most people in the UK fly once a year or not at all in any given year. The more you go into people who are wealthy or extremely wealthy, the more you get higher levels of aviation—you get frequent flying up to the very luxury end with things like private jet use.
Something like a frequent flyer levy could really help to constrain demand. We produced a report with the New Economics Foundation last year that looked at a very administratively simple way to do that and target the 3% of people who take 30% of all the flights. That kind of policy would be really fair and popular, and it would increase tax take from the sector, which is incredibly undertaxed. It also really needs to include a tax on the fuel burned. Something like that could relatively painlessly take out a huge chunk of aviation demand, completely undo any perceived case for Heathrow expansion and increase tax take.
It would also take the strain off the technological solutions, because delivering a smaller scale of alternative fuels and carbon reductions would be easier. Most people would be unaffected, and it would avoid the kind of situation where any increases in prices that will have to come as a result of things like airport expansion and the costs of decarbonisation technologies are levied in an unfair way. Even airlines are saying that Heathrow expansion will hugely increase costs, so a sensible solution is to not have airport expansion. Tax the frequent flyers and protect access to occasional flights for ordinary people.
Q132 Chair: Can I ask the question the other way round? Is it realistic to expect aviation emissions to reduce without some kind of demand management?
Alethea Warrington: It is completely unrealistic. The level of technology deployment is completely fantasy-based. Demand reduction would make the technological lift so much easier—it would be a safety/insurance policy. If at some point the aviation industry is exceeding its expectations and it has delivered all these amazing technologies and everything is fantastic, there is nothing to stop them expanding at that point, but that is so far from where are right now.
Dr Pennington: Yes. Emissions have to be capped. When we look at the technology solutions being so far behind, the only lever that remains is looking at demand. It does not have to be an either/or. If demand is capped or limited, technological solutions will come—they are coming—but it is about the timing. What can we do now to reduce emissions as we know we need to? That is about looking at demand, and then, when you get into the future, once the technology is there, that is when you can start to look at making more space.
Celeste Hicks: Demand management is in the HENPS forecast. If you look at what I said earlier about the terminal capacity coming online, there is a modelling assumption in there that the third runway has been built by around 2035, but it does not fill up for three years because the terminal that goes with it to allow the passengers to use it has not been built. That is during carbon budget 6—even during that time, it will not fill up because there will be terminal capacity constraint. That thinking is in the modelling already. You basically cannot just let all the airports expand and all the passengers come, which goes back to the point about displacement.
Q133 Jacob Collier: If the key decarbonisation assumptions are not met, what do you think the contingency plan should be?
Alethea Warrington: The Government need to think really seriously about constraining the total amount of flights, whether that is constraining demand or capacity, or putting maximum limits on emissions. To some extent, there is a contingency plan expressed in the jet zero strategy in terms of the five-yearly reviews. We think that every five years is not often enough; it would ideally be yearly. Also, we are at the point now where the technological solutions are demonstrably failing to be delivered, and face huge barriers to delivery, so the Government should be putting in contingency plans until the aviation sector is actually delivering decarbonised flights.
Q134 Jacob Collier: You have just said that the climate targets should be reviewed every year. Are the other panellists in agreement with that?
Dr Pennington: The progression towards the targets should be looked at every year, or if, for example, a major sustainable aviation fuel plan or greenhouse gas plan is cancelled, that should be reviewed as well, because we have seen quite a few large-scale cancellations in the last few years that will have a significant impact on the quantity of SAF.
Celeste Hicks: Yes, if you look at the technology development scenario in the aviation forecast, even in the “techno-optimistic” scenario, which is equivalent to the jet zero high-ambition one, it is now 28 megatonnes, whereas it was 19 megatonnes in 2022. Even in four years, we have gone from 19 to 28, and that is now that the SAF policy has come online. If you leave it five years, we are likely to find then that we are actually 35 megatonnes behind, so I think there need to be earlier reviews.
Q135 Steff Aquarone: Thinking about the wider economic impacts of Heathrow expansion, are there particular risks to local biodiversity and broader biodiversity that you think we should be aware of?
Alethea Warrington: Obviously, there will be local harmful impacts, with things such as protected areas, rivers, woodland and green space being lost. There will also be an increase in noise and air pollution over London. More broadly, there are the climate impacts that we are already seeing. Over the past year, there have been floods, wildfires and extreme temperatures. Allowing Heathrow’s emissions to push the UK over its carbon budgets would have a serious impact.
Going back to the broader economic point, the HENPS analysis also made it clear that the overall economic impact of the third runway would be really harmful, with up to £62 billion in overall negatives. Of course, with the UK’s aviation sector, when increased capacity comes online, it very much goes to the people who already fly most often, who then take more outbound flights and export more tourism spend.
There is just not anything even vaguely resembling a convincing economic case for why this should go ahead. If we want jobs, we could get a lot more jobs for much lower emissions elsewhere, supporting the UK’s domestic economy rather than taking resources out of it. Given the risk to the climate, the lack of an economic case and all the local impacts, it is very difficult to see any convincing argument at all about why this is worth it. The HENPS does not provide enough of a safeguard against that.
Celeste Hicks: I do not want to prejudge what is coming in the next session, but I believe that the health impacts of PM2.5 are not monetised in the WebTAG assessment. We also think that they did not monetise the noise impacts identified by the ANNE and ANAS studies, which came out in the summer and basically showed that annoyance from aircraft noise occurs at much lower levels than previously thought. For us, those are big omissions: the emissions of PM2.5 and the ANNE and ANAS noise levels. By the way, those are both WHO-recommended levels, and they have just been left out of this. But, again, I know that you will probably talk about that in the next session.
Q136 Steff Aquarone: Dr Pennington, is there anything in particular on biodiversity that we should know about?
Dr Pennington: I would just underline the effect that we know climate change is already having on biodiversity. Of course, there are the local impacts of Heathrow on the wildlife there, and there is a significant amount of infrastructure and construction that would need to be done, but, as the world is heating up, we are seeing a devastating impact on biodiversity worldwide, so that should 100% be accounted for as well.
Q137 Barry Gardiner: On the biodiversity side, I am looking at the main obligation on SAF, which rises from 2% to 10% and then up to 22% in 2040. I wonder whether you could talk about HEFAs—hydrogenated esters and fatty acids—because that is the most successful, yet it is being reduced over the period. Can you comment on what that is going to do, and the transition to what they are calling the third level of SAF?
Dr Pennington: On the HEFA side, as Ali already mentioned, there was a great Royal Society report that looked at the fact that this is a very finite resource. We also use HEFA to make biodiesel, which of course is being used in other transport sectors to decarbonise, so it is under a lot of competition. For that reason, there is a cap in the mandate as to how much of it can be HEFA, and it reduces, like you say.
The transition to these advanced sustainable aviation fuels—called power-to-liquid or eSAF—basically relies on high amounts of electricity, and they are very expensive to run. Looking at the future of the whole economy and the way it is going as we decarbonise, we are becoming very reliant on electricity—transport and other sectors are becoming electrified. That is where the risk comes. That does not mean that we should increase the HEFA cap, but that we should be realistic about what the technologies are and what scale they are going to arrive on. The power-to-liquid eSAF is looking very dry.
Q138 Barry Gardiner: If I can tease out what this means, we are moving to a future of SAF that is as yet untested and extremely expensive. The reason that we are decreasing the amount of HEFAs is the impact on the wider economy. But is it not also because of the impact on food production, because we need that land for food production, and therefore, there are wider biodiversity and sustainability impacts here? I want to be clear on how this teases out in different ways.
Dr Pennington: In the SAF mandate in the UK, crop-based biofuels are not eligible to be used, so in that sense, it will not have an impact. On waste oils and fats, most of which are imported, it becomes a bit harder to verify when we are importing them from abroad.
Q139 Barry Gardiner: So your point earlier about the future being one where everybody is trying to get their own SAF means that that supply will be reducing, and in the UK we are not allowed, because of the impact on farming, to switch over to producing it that way ourselves?
Dr Pennington: Yes. Crop-based biofuels would not be eligible under the mandate, so I cannot imagine a world where they would use them.
Celeste Hicks: I will just point out that the DFT did a call for evidence earlier in the year about what the impact would be on food and land security if they did include crop-based biofuels. Our interpretation of why they did that was because they knew that the HEFA cap was coming in and that the HEFA supply was constrained. You cannot increase the amount of used cooking oil in the world—you just cannot do it to the extent that we need. In the absence of PtL coming online in those requirements, they were considering other options and one of them would be crop-based biofuels. We have not heard any update on it yet, but it has been discussed at least.
Chair: Thank you. That brings this panel to an end. I would like to thank you all very much for the evidence and the time you spent preparing for today. As I said, if you feel that there was something else you would like to add, please do write to us.