I wrote a long comment, copied it to fix a typo, deleted, and then discovered I hadn't actually copied it.
But the summary is:
You can divide air travel into four. One can be replaced by the new battery-electric planes there will be in the 2030s - Heart Aerospace have 200+ orders for their 19-seater, and there are others making similar progress. One can be replaced by high-speed rail. And the other two cannot be replaced as is.
The electrifiable option is short-distance low-demand routes, usually to islands (e.g. flights to Shetland) or to very very low-population areas (e.g. the Australian Outback). These are usually subsidised by city-dwelling taxpayers, and paying a little more for electric planes, especially given the noise-pollution advantages, should not be impossible. They claim these will be in service in 2026, but I don't believe them and expect it to be more like 2030.
The high-speed rail option is short-distance high-demand routes overland. Europe, the US Northeast/Midwest, China, Japan, etc. China has the longest routes and now has a few high-speed sleepers; Europe's routes are getting longer as the national networks get connected together and sleepers make sense for 1000km to 2000km routes, which should cover most of the continent.
The two that can't be replaced are short-distance high-demand routes overseas, such as flights to Ibiza or Majorca; only people who can't fly will be interested in a long ferry journey (it takes far too long).
And the other is longer distances. Anything over about 2000km means at least day and a night on a train, and many such distances include crossing an ocean; ocean liners do exist, but they take a week to cross the Atlantic and two to cross the Pacific. No-one is going to take multi-day journey over an eight hour flight.
Ferries are much more fuel/emissions efficient than flights; liners are a bit better than flying, but nothing to write home about; cruise ships have about the same emissions per passenger-km as flying; trains can potentially be zero emission once we decarbonise electricity which we are doing anyway.
One thing I’d like to add. Yes, aviation does not represent a large proportion of total CO2 emissions, but aviation’s impact on the climate mostly comes from non-CO2 impacts. Though this would add to your argument that aviation is just incredibly difficult to decarbonise.
Two papers worth checking out that discusses this:
Aug 5, 2022·edited Aug 5, 2022Liked by James O'Malley
A couple of titbits here. Excess private aviation is a very low-hanging fruit for any government; rather than rationing out holidays to their populations, there could be more progressive taxation of HNWI taking 15 min flights to offset some of the carbon.
Where there is the ability to use an efficient and attractively priced railway, people will and do use it. We are seeing more of this domestically in Europe with actual competition on some routes, which could be the start to an equivalent of the 1990s LCC boom in aviation. Paris CDG- London Heathrow was the most popular route for Heathrow in 1994, with almost 3m passengers. Twenty-five years later, it was about half that despite Heathrow growing by nearly 80% in that period.
Within the UK, many domestic flights in/out of Heathrow are driven by connections. A typical flight would only have around half the passengers flying point-to-point; for some routes and times of day, it is close to zero. Not so much the case for INV and ABZ but certainly LBA, MAN and to a lesser extent, EDI and GLA see a lot of interlining.
This is why not fully integrating HS2 at Heathrow was a mistake; the ability to replace the domestic air connection with a rail one was a lost opportunity.
The result of flying is great, but the process itself is really tedious and uncomfortable. It's quite often more efficient to take trains than to fly, even if it takes longer by train, because you don't have luggage limits and you usually have more space to put a laptop down or something, and you're generally on a train for (say) ten hours in one block, rather than seven hours all chopped up into little bits where you can't get anything done if you're flying. I know that's nothing to do with environmentalism, but I think that, as long distance train travel becomes easier in Europe, it'll have as much to do with modal shift as green concerns. It's just a nicer way to travel, and often not much slower at all than flying.
The difficulty with this I think is that flight is (relatively speaking) a luxury good, so it’s a very disproportionate chunk of emissions in terms of “emissions produced -> people benefitting” AND as the world’s middle class continues to grow, that sliver is only going to get bigger. I tend to agree that demonising things isn’t hugely helpful, but I think it’s definitely wrong to think that demand management isn’t a big part of the solution - in the same way that telling everyone who eats meat that they’re terrible and saying that everyone has to be vegan is a losing argument, but saying we could all do with reducing our meat intake (and that actually we can do this by quite a lot without massively noticing) is a no brainer. And unfortunately, while it’s true that short haul flights make no sense, they’re also a much smaller part of the problem than long haul flights emissions wise.
The comparison with insulation and home heating is apposite because it’s a perfect example of a dynamic present in loads of decarbonisation - we need to change the energy vector (from gas to electricity, boilers to heat pumps) but we also just need to use less energy (efficiency, insulation). They’re both important. At some point we will need to actually decarbonise aviation (I’m not as pessimistic as you on the possibility but agree it’s decades away), but we also need to do less of it.
P.S green hydrogen also looks quite good for steel btw (but, same dynamic - we could and should also industrially recycle waaaay more steel)
Interesting points as ever, I think there’s two aspects that challenge this:
-the data looks to be from 2020, an incredibly atypical year for flights. In 2017 flights were 7% of uk emissions which is a much larger contribution. Flights are also very easy to reduce compared with the challenge of things like insulating homes, or building new power plants.
- they are very often a discretionary and luxury good. In 2018, 10% of UK flyers took over half of trips, 1% of flyers took about 20% of flights. On the other hand 48% of people didn’t fly. Maintaining the same level of flights means cutting emissions for everyone to protect the lifestyles of a relatively more affluent minority
Very late comment, but I enjoyed this and had a few thoughts:
- I think other commenters are right - air travel is fun and abundance is great, whatever Matt Yglesias said, etc. But consumption is so disproportionately by the wealthiest people in the wealthiest countries that it's not a particularly shared benefit. And increasing everyone's consumption up to that high level would make that 1.9% of global emissions (or 3-5% depending on what you read) look a lot worse. DAC is inevitable but will be very energy intensive - at the current margin I'd be pretty surprised if it wasn't economically more efficient to not take one flight rather than try to remove its emissions. So at least some demand management still seems important to me.
- A couple of people have suggested some kind of progressive price on air miles (and maybe also seat class?), which would be definitely fairer and maybe more politically palatable. I'd guess this would mainly affect business travel, which gives obvious concerns about stifling innovation and growth etc. I haven't seen it yet but hopefully someone can get some insight into this from the big natural experiment we've just had where everyone stopped business travel for a year.
- Interesting take on Insulate Britain. It's an idea I see a lot from more wonky types, which is that campaigners/activists should focus on boring but important technical issues. I'm not sure this is right - the problem is Insulate Britain (and similar groups) is mostly a mix of middle class retirees and professional activists, neither of whom have any particular technical expertise. So they can't act like think tanks and work on solutions - all they can do is try and raise attention. I don't think the public is super interested in boring but technical issues, and I also think it's notable that IB haven't really achieved much media discussion of insulation other than a couple of explainers in i or whatever.
I actually think that XR, although they cocked it in the end, was extremely successful in shifting the narrative on climate and motivating the net zero target. And I think a lot of this was it was very simple and accessible - you didn't really have to know anything to support it, you just had to go to a street party on Waterloo Bridge and maybe waste some police time if you were feeling brave. They also explicitly didn't offer solutions, which meant there was no chance for the message to get bogged down in nitty gritty and fizzle out - it was just a loud 'this is bad, someone needs to do something', which gets traction
It'd be interesting to know what percentage of aviation emissions come from private flight. Or to know how many emissions come from the most active fliers. I have seen elsewhere the wealthiest ten percent are responsible for fifty percent of emissions as a whole (even within a national population), so i imagine a similar proportion would be seen in the aviation sector among the most active fliers.
I wrote a long comment, copied it to fix a typo, deleted, and then discovered I hadn't actually copied it.
But the summary is:
You can divide air travel into four. One can be replaced by the new battery-electric planes there will be in the 2030s - Heart Aerospace have 200+ orders for their 19-seater, and there are others making similar progress. One can be replaced by high-speed rail. And the other two cannot be replaced as is.
The electrifiable option is short-distance low-demand routes, usually to islands (e.g. flights to Shetland) or to very very low-population areas (e.g. the Australian Outback). These are usually subsidised by city-dwelling taxpayers, and paying a little more for electric planes, especially given the noise-pollution advantages, should not be impossible. They claim these will be in service in 2026, but I don't believe them and expect it to be more like 2030.
The high-speed rail option is short-distance high-demand routes overland. Europe, the US Northeast/Midwest, China, Japan, etc. China has the longest routes and now has a few high-speed sleepers; Europe's routes are getting longer as the national networks get connected together and sleepers make sense for 1000km to 2000km routes, which should cover most of the continent.
The two that can't be replaced are short-distance high-demand routes overseas, such as flights to Ibiza or Majorca; only people who can't fly will be interested in a long ferry journey (it takes far too long).
And the other is longer distances. Anything over about 2000km means at least day and a night on a train, and many such distances include crossing an ocean; ocean liners do exist, but they take a week to cross the Atlantic and two to cross the Pacific. No-one is going to take multi-day journey over an eight hour flight.
Ferries are much more fuel/emissions efficient than flights; liners are a bit better than flying, but nothing to write home about; cruise ships have about the same emissions per passenger-km as flying; trains can potentially be zero emission once we decarbonise electricity which we are doing anyway.
Hi James,
Interesting read!
One thing I’d like to add. Yes, aviation does not represent a large proportion of total CO2 emissions, but aviation’s impact on the climate mostly comes from non-CO2 impacts. Though this would add to your argument that aviation is just incredibly difficult to decarbonise.
Two papers worth checking out that discusses this:
https://www.sciencedirect.com/science/article/pii/S1352231020305689
https://iopscience.iop.org/article/10.1088/1748-9326/ac286e
A couple of titbits here. Excess private aviation is a very low-hanging fruit for any government; rather than rationing out holidays to their populations, there could be more progressive taxation of HNWI taking 15 min flights to offset some of the carbon.
Where there is the ability to use an efficient and attractively priced railway, people will and do use it. We are seeing more of this domestically in Europe with actual competition on some routes, which could be the start to an equivalent of the 1990s LCC boom in aviation. Paris CDG- London Heathrow was the most popular route for Heathrow in 1994, with almost 3m passengers. Twenty-five years later, it was about half that despite Heathrow growing by nearly 80% in that period.
Within the UK, many domestic flights in/out of Heathrow are driven by connections. A typical flight would only have around half the passengers flying point-to-point; for some routes and times of day, it is close to zero. Not so much the case for INV and ABZ but certainly LBA, MAN and to a lesser extent, EDI and GLA see a lot of interlining.
This is why not fully integrating HS2 at Heathrow was a mistake; the ability to replace the domestic air connection with a rail one was a lost opportunity.
(Declaration; I work in aviation)
The result of flying is great, but the process itself is really tedious and uncomfortable. It's quite often more efficient to take trains than to fly, even if it takes longer by train, because you don't have luggage limits and you usually have more space to put a laptop down or something, and you're generally on a train for (say) ten hours in one block, rather than seven hours all chopped up into little bits where you can't get anything done if you're flying. I know that's nothing to do with environmentalism, but I think that, as long distance train travel becomes easier in Europe, it'll have as much to do with modal shift as green concerns. It's just a nicer way to travel, and often not much slower at all than flying.
The difficulty with this I think is that flight is (relatively speaking) a luxury good, so it’s a very disproportionate chunk of emissions in terms of “emissions produced -> people benefitting” AND as the world’s middle class continues to grow, that sliver is only going to get bigger. I tend to agree that demonising things isn’t hugely helpful, but I think it’s definitely wrong to think that demand management isn’t a big part of the solution - in the same way that telling everyone who eats meat that they’re terrible and saying that everyone has to be vegan is a losing argument, but saying we could all do with reducing our meat intake (and that actually we can do this by quite a lot without massively noticing) is a no brainer. And unfortunately, while it’s true that short haul flights make no sense, they’re also a much smaller part of the problem than long haul flights emissions wise.
The comparison with insulation and home heating is apposite because it’s a perfect example of a dynamic present in loads of decarbonisation - we need to change the energy vector (from gas to electricity, boilers to heat pumps) but we also just need to use less energy (efficiency, insulation). They’re both important. At some point we will need to actually decarbonise aviation (I’m not as pessimistic as you on the possibility but agree it’s decades away), but we also need to do less of it.
P.S green hydrogen also looks quite good for steel btw (but, same dynamic - we could and should also industrially recycle waaaay more steel)
Hi James,
Interesting points as ever, I think there’s two aspects that challenge this:
-the data looks to be from 2020, an incredibly atypical year for flights. In 2017 flights were 7% of uk emissions which is a much larger contribution. Flights are also very easy to reduce compared with the challenge of things like insulating homes, or building new power plants.
- they are very often a discretionary and luxury good. In 2018, 10% of UK flyers took over half of trips, 1% of flyers took about 20% of flights. On the other hand 48% of people didn’t fly. Maintaining the same level of flights means cutting emissions for everyone to protect the lifestyles of a relatively more affluent minority
Source: https://www.theguardian.com/environment/2019/sep/25/1-of-english-residents-take-one-fifth-of-overseas-flights-survey-shows
Very late comment, but I enjoyed this and had a few thoughts:
- I think other commenters are right - air travel is fun and abundance is great, whatever Matt Yglesias said, etc. But consumption is so disproportionately by the wealthiest people in the wealthiest countries that it's not a particularly shared benefit. And increasing everyone's consumption up to that high level would make that 1.9% of global emissions (or 3-5% depending on what you read) look a lot worse. DAC is inevitable but will be very energy intensive - at the current margin I'd be pretty surprised if it wasn't economically more efficient to not take one flight rather than try to remove its emissions. So at least some demand management still seems important to me.
- A couple of people have suggested some kind of progressive price on air miles (and maybe also seat class?), which would be definitely fairer and maybe more politically palatable. I'd guess this would mainly affect business travel, which gives obvious concerns about stifling innovation and growth etc. I haven't seen it yet but hopefully someone can get some insight into this from the big natural experiment we've just had where everyone stopped business travel for a year.
- Interesting take on Insulate Britain. It's an idea I see a lot from more wonky types, which is that campaigners/activists should focus on boring but important technical issues. I'm not sure this is right - the problem is Insulate Britain (and similar groups) is mostly a mix of middle class retirees and professional activists, neither of whom have any particular technical expertise. So they can't act like think tanks and work on solutions - all they can do is try and raise attention. I don't think the public is super interested in boring but technical issues, and I also think it's notable that IB haven't really achieved much media discussion of insulation other than a couple of explainers in i or whatever.
I actually think that XR, although they cocked it in the end, was extremely successful in shifting the narrative on climate and motivating the net zero target. And I think a lot of this was it was very simple and accessible - you didn't really have to know anything to support it, you just had to go to a street party on Waterloo Bridge and maybe waste some police time if you were feeling brave. They also explicitly didn't offer solutions, which meant there was no chance for the message to get bogged down in nitty gritty and fizzle out - it was just a loud 'this is bad, someone needs to do something', which gets traction
It'd be interesting to know what percentage of aviation emissions come from private flight. Or to know how many emissions come from the most active fliers. I have seen elsewhere the wealthiest ten percent are responsible for fifty percent of emissions as a whole (even within a national population), so i imagine a similar proportion would be seen in the aviation sector among the most active fliers.
Also, is military aircraft included here?