Dr Sally Cairns, University of Leeds: Fairness and reducing emissions from air travel

Dr Sally Cairns: um, it's it's great to be here despite the horrible weather um and I've been asked to talk about the nature of air travel on the fairness of reducing emissions and flying. So to start with some background information on the number of passengers travelling through UK airports every year. In 1990 it was about 100 million. Since then, it's been going up dramatically. It dipped down after the financial crash in 2008 because it was something that people cut back on. But it's grown again and it's now at about 300 million.

The forecast accompanying the government's current policy is for further growth of about 50% to 450 million. But there are a range of forecasts, depending on policy decisions, and they go from less than 400 million to more than 500 million passengers a year. In terms of who those passengers are, about 9% are international travellers changing planes in the UK, 12% are people on domestic flights flying within the UK. The biggest section by far is UK residents taking leisure trips abroad, and about 1/4 of those are visiting family and friends and about 3/4 are holidays. The second biggest group is international leisure trips by overseas visitors coming here and finally, about 13% of passengers are making international business trips.

In terms of what's changing over time for UK residents. In the last 10 years, there have been reductions on domestic flying, so flying within the UK and there have been reductions in the number of business trips by air. But there has been a big increase in international leisure, and the trends are different for different age groups. So today's 16 to 24 year olds are flying a lot more than 16 to 24 year olds did 10 years ago. But for example, there's been small reduction in trips by 0- 15 year olds, so the growth does not seem to be coming from family holidays, or at least not families with younger children. In terms of where UK residents fly, about 1/4 of all international air trips go to Spain and over 3/4 go to Europe, but the rest of the world is very important, those longer distance trips because they account for a greater proportion of emissions and long haul trips account for over half of all passenger kilometres.

From the information that you've had so far, I think it would be really difficult to understand why there is so much media focus on flying and I think you can only really understand this if you look at the emissions from an individual flight in the context off emissions from other activities. So as context, in 2017, emissions through all the road and rail travel in the UK were equivalent to about 1.8 tonnes of carbon dioxide per person. The bottom half of the slide there is estimates for three individual flights of different lengths and the figures are taken from a variety of reputable online calculators. As you can see, there's quite a variation in those numbers and that's because those calculators use different estimates about plane fuel efficiency and they vary in terms of whether they include the other climate effects of planes in the CO2 figures. What you can see is that as the journey gets longer, unsurprisingly, the emissions go up. By the time you get to a return trip from London to Sydney, even the lowest estimate suggests that just one trip is equivalent to a whole year's worth of road and rail emissions from the average person. In terms of whose flying, some people fly much more than others. So in a typical year, about half of the population does not fly. Of course, that means that the other half does, but even off those who fly, some people fly much more than others on. For example, 15% of people take 70% off all flights. Whether people fly is strongly related to income.

In this graph, I've taken all households and split them into five income groups. So the column on the left is for the 20% of households with the lowest income and, as you can see from the green colour, about 70% off those households do not taken overseas flight in a typical year. On the other hand, the column on the right hand side is for the 20% of households with the highest household income and here it reverses in a typical year 70% of those households don't take an overseas flight Flying is also very unevenly spread across the country. About half off all air trips start or finish in London and the Southeast and if you compare UK I travel to other countries, if you include the flights that people make within their own countries, you get a different picture. But for the UK, international air travel is the particular issue for emissions and what this shows is that actually, British people take more international air trips than any other the residents of any other country in the world, and that includes the USA and China.

Finally, I was asked to talk about the effects off limiting airport expansion and we do have it some insights into that from government forecasts they have one forecast looks at what will happen to passenger numbers if there are no limits on airport size, and in that forecast you get about 494 million passengers by 2050. Alternatively, they have a scenario where they say, well, what will happen if existing airport limits stay in place so Heathrow doesn't get a third runway and all the other airports across the country that are able to increase their maximum operating capacity are refused. In that scenario, you get 410 million passengers in 2050. That is still growth. Remember, were about 300 million passengers at the moment. But of course, it is a lower level of growth. What the pie chart then does is try to look at the difference between those two, the 84 million passengers that you don't get on. What you can see is that over half of those, about 48 million are people - international travellers who would otherwise change planes in the UK, and the second biggest group is 26 million leisure trips that UK residents would otherwise make abroad. The effect on the number of trips by overseas residents coming here for leisure or on business travellers is much less. In terms of what that means there could be many implications, I think the most obvious ones, obviously less growth in jobs and income for airlines and airports than they would otherwise have, and the other main implication is that it would be harder to operate less popular routes.

So the main argument for wanting people to change planes in the UK is it enables us to fill up services that would otherwise be uneconomic. On the other hand, I think that the big win could be the UK tourism, because a lot of those international leisure trips by UK residents might well be made to UK destinations instead of abroad. And the other obvious impact from limiting airport expansion would be fewer people impacted by airport noise and pollution. Thank you. Thank you very much.