Not just carbon: the problems with planes

A plane flying over Uilenstede on approach to Schiphol Airport

Much is made of the carbon emissions associated with flying - and quite rightly. Although they represent a fairly small percentage of total annual emissions, because people fly a lot less often than they drive or use electricity, it is much more emissions-intensive than other everyday practices. Figures from the UK show that a short domestic flight generates about 1.5 times as many emissions per passenger-kilometre than driving a car alone; and more than 6 times as many emissions as taking a domestic train. But the emissions aren't the only problem associated with flying.

When I was in Amsterdam, I lived in the student accommodation village called Uilenstede (1), which is in the southern part of Amsterdam, quite close to Schiphol Airport. Not only is it close to the airport, but depending on which way the wind is blowing (and therefore which runways they're using that day) it is often directly below the flight path of planes coming in to land. In busy times, you could hear a plane on its noisy final approach around once every sixty seconds.

The eastern approach into Schiphol over Uilenstede (via Google Maps)

Noise pollution from airports is more than just an annoyance or inconvenience - it can have a lot of pretty negative health impacts. It can disturb sleep, increase stress, reduce cognitive function, and increase the risk of a range of cardiovascular diseases. Given that noise pollution from airports overwhelmingly affects working class neighbourhoods, there is a pretty strong equity problem with lumping all of these health burdens onto those who can least afford them.

Now, you might make the point that the people who buy a house near an airport know that the airport is there. It's certainly not a surprise - airports don't spring up overnight, so it was likely there when they bought the house, and generally the price of the house will be lower than a comparable house in another suburb, reflecting the downward pressure the noise pollution has on prices in the area. I'm not without sympathy to this line of argument - certainly, it makes me very angry when people buy a house near a pub and then complain about the noise. If you buy a house near an airport you do it in the knowledge that it might be a bit noisy.

But this is a question of individual choice, given certain policy settings - "the airport is there, should I buy a house near it?" We need to be thinking in terms of which policy settings are best - and from that perspective, it's not so straightforward.

The huge size of Melbourne Airport, compared with the CBD

Land use

Looking at it from the policy angle gives some useful perspective, I think. Modern airports - those required for large jumbo jets - require huge concessions of space in a city. The airport itself takes up a huge amount of room, but then you also need to consider the depressed value of the land around it, particularly the land directly below the paths of arriving and departing aircraft. Space is pretty much the most valuable commodity there is in a city - which is why things like cycling and public transport and mixed-use medium-density development are so important - and airports either use, or limit the use of, a hell of a lot of that space. You can of course ameliorate this to some extent by placing the airport further away from the city it serves - but then you increase the problems with providing strong transport links to the airport, which are never cheap or easy to solve. There aren't any silver bullets to deal with these land-use problems - it's always going to be a tradeoff.

The proposed alignment of the Melbourne Airport Rail Link

It wasn't always this way - before the jet age, planes required much shorter runways so airport footprints were much smaller. (There was even a semi-credible plan to build runways on top of Kings Cross station so people could commute to London by plane). But the bulk of the proposals to decarbonise the aviation industry are working on pretty similar assumptions to the jet age - large planes, travelling quickly, using long runways. There are of course pie-in-the-sky ideas about using Vertical Take Off & Landing (VTOL) to eliminate the need for long runways - there always are, and there have been since the early days of the jet age. They've been able to get this to work well for small, light, slower aircraft (eg helicopters or drones) or fast but equally small and specialised craft (like fighters) but not for big, fast, long-distance craft to carry bulk passengers or freight; for these, we'll probably be using long runways for the foreseeable future.

The very limited success VTOL has had has been with small fighter-style aircraft (via Julian Herzog)

Noise pollution

From a noise perspective, the next generation of planes - whichever tech wins - are likely to be roughly as noisy as the existing ones, too. When you hear a plane, you're not really hearing the explosions of the jet fuel igniting in the engines as such, you're mostly hearing the huge amount of air that is displaced by the plane - as thrust through the engines, and flowing over the body. So if we replace engines that burn AvGas with ones that burn carbon-neutral hydrogen, biofuels or synfuels, they will probably be almost exactly as noisy as the existing ones. Battery electric planes are looking unlikely to be viable for long-haul flights in the short term, but even these aren't likely to be very quiet, because they are still fundamentally moving a hell of a lot of air around, and that is an inherently noisy thing to do.

All of which is to say - if all we do to reform the aviation industry is decarbonise it, and we leave everything else the same, we are still going to be stuck with all of these problems. And these problems should be taken into account when we think about how our freight and passengers should get around this country.

Eurostar high-speed train at Amsterdam Centraal Station

It is pretty clear that for really long distances, and particularly trips that cross oceans, flying is the most viable option for the foreseeable future. High Speed Rail has a fighting chance connecting the east coast of Australia and Adelaide, but the distances - and the lack of large settlements along the way - make it impractical for Perth or Darwin. Ferries work okay to link Victoria and Tasmania, but they're clearly not going to be very competitive when linking Australia and New Zealand - without even thinking about linking, say, Sydney to Los Angeles. So clearly some amount of aviation is going to be with us for a while, and efforts to decarbonise it are necessary.

But we also need to be clear that reducing the amount of flights we take has more benefits than just on the climate front. If we can reduce domestic and other short-haul flights in Australia and around the world, and make it so that it's only those long-distance/overseas destinations that are served by planes, we can help reduce pressure to build new, larger airports, which will inevitably be further away from city centres than the old ones. We can reduce pressure to expand the footprints of existing airports. And we can more easily fit flights into waking hours, making it easier for nearby residents to get a decent night's sleep.

So when we talk about the value of High Speed Rail projects for Australia, or about improving freight rail links, let's keep in mind - reducing the number of flights is not just about decarbonisation. Planes cause enough problems that reducing flights is a good end in and of itself.

(1) I had no idea how to pronounce this when I first arrived, so FYI for fellow English-speakers: it's pronounced OWL-uhn-STAYD-uh, and it loosely translates as "the owl's place" or "the owl's home".