Where's my error?

[fivemack]

I've often heard arguments like 'the cost of flying should reflect its externalities', where the clear implication was that this would make it so expensive that people would stop doing it, or so expensive that it would clearly be cheaper to take a train.

On the whole I'm strongly in favour of air travel - at least, I'm strongly in favour of at most one-level-vicarious personal experience of strange far-off places, and air travel is the only realistic way to get anyone there; going over land to Bangkok is significantly more expensive than Thai Air even if time and ludicrous inconvenience are not a constraint, the price of the return plane ticket won't get me a train beyond about Moscow.

Yes, it takes a lot of energy to remove one ton of CO2 from the air: http://nextbigfuture.com/2009/06/co2-removal-from-atmosphere.html says fifty kilojoules per mole which is 1.2 gigajoules per ton, http://www.futurepundit.com/archives/005592.html is optimistic and says a third of that.

A gigajoule is about 300 kilowatt-hours, so about thirty pounds worth of electricity at the price I pay for it as a domestic user on a not-terribly-good-value tariff. Say the cost-of-capital and depreciation for CO2-removal equipment is about the same as the electricity; so the total cost for taking CO2 out of the atmosphere would be sixty pounds a ton.

Even people strongly against CCS no-net-CO2 coal-fired electricity generation argue that the efficiency cost of doing the CCS would be about 30%, the currently-4GW facility at Drax would produce 2.5GW; say this doubles the price of the electricity and we're talking a hundred pounds a ton.

One of Easyjet's A319 planes burns 850 gallons of fuel an hour to transport say 120 people (capacity is around 150); jet fuel produces about a ton of CO2 per hundred gallons burned, so taking your 120 people two hours to Berlin has produced about twenty tons of CO2. Removing which would put £17 a head on the cost of the flight; Easyjet is nothing if not cheese-paring, so it probably wouldn't put £30 a head on the price of the ticket. +30%. The last time I compared the prices, Easyjet to Berlin was £100 return and rail was £400 one way.

A Eurostar train carries 750 people two hours from London to Paris and uses 12.5 megawatts of electricity to do so; 25 megawatt-hours at a kilo of CO2 per kilowatt-hour for UK electricity generation [yes, I know most of the French electricity is fission-produced] is 25 tons, so about the same amount of CO2 as the A319 to get six times as many people about half as far. I don't have the figures for slower trains.

A 747 with its 400 passengers burns about a gallon of fuel a second, say produces 36 tons of CO2 per hour, it's eleven hours to San Francisco so that's 400 tons, £24000 to remove. A hundred pounds per passenger per direction; say £250 on the price of the return ticket. +30% again, maybe a bit worse if you're flying at very off-peak times and can get a cheaper base ticket.

Flights aren't the overwhelming part of the cost of foreign holidays now; making them 30% more expensive doesn't seem likely to stop people travelling, and if doubled electricity bills and somewhat more expensive holidays are the price I have to pay to keep London (and incidentally Bangladesh, for there is only one sea level) above water, I'll pay gladly.

Comments

[monkeyhands.livejournal.com]

Thanks for this post and for raising this topic. As someone who often comes out with the "the cost of flying should reflect its externalities" argument, can I point out a couple of problematic assumptions in your post? Then I'll try to explain my own perspective.

1. You're assuming that "the extra CO2 cost of air travel" = "how much it would cost for the electricity used in removing the extra CO2 from the air". The CO2 removal technology has only just been invented. It's not in widespread use and we have no idea if/when it will become more widely used. We can also assume that the creators of this technology will want to make a profit on their invention. That means that the likes of Easyjet can't at the moment make their emissions go away just by paying the electricity bill for the CO2 removal.

2. You're not taking radiative forcing into account. Radiative means that the climate-changing effects of aviation are about 2.8 times greater for exactly the same emissions. So if a flight and a train journey have identical emissions per passenger mile, the flight will be 2.8 times more damaging to the climate.

3. You're also forgetting about the Chicago Convention, which exempts air fuel from tax. This gives air travel a big, unearned advantage over train travel. I believe that unpaid tax is an externality too, even if it doesn't directly relate to climate change. The rise in Air Passenger Duty a couple of years ago was an attempt to make air travel pay for the environmental damage it causes through tax, but it's a tax on carriage, not fuel, and it still doesn't compare to the taxes that a train operator would pay on their fuel.

[monkeyhands.livejournal.com]

4. Even if you could hoover a given flight's total emissions out of the air and passengers paid for that hoovering through the ticket price, that still wouldn't cover all the externalities of aviation. Why?

Firstly, because your calculations assume that passengers will be paying only for the cost of cleaning up the flight they've just been on. But the problem with aviation is that you get "ghost flights", where airlines run completely empty flights in order to retain their landing slots. It's insane from a green point of view, but economically rational because landing slots are so coveted.

Secondly, because your calculations don't take into account the other externalities of aviation, such as noise pollution or people being forced to leave their homes so that someone can build a runway.

[(Anonymous)]

They must be desperate for people to go on these ghost flights, so tickets must be really cheap. How can I get on them?

S.

[monkeyhands.livejournal.com]

Some airlines do advertise, but it's not as easy for the passenger as getting on a regular flight, because ghost flights are often cancelled at short notice. (Cancelling individual flights on an ad-hoc basis, as opposed to cancelling uneconomic routes, is another tactic for keeping your landing slots.)

[(Anonymous)]

Oh, that makes them sound a lot less bad from a green point of view, doesn't it? A cancelled flight doesn't use any fuel.

But then 'Airlines sometimes cancel empty flights' isn't as good a slogan.

S.

[monkeyhands.livejournal.com]

OK, I shouldn't have said "often". Airlines have to actually use about 80% of their landing slots to avoid losing them, so empty flights get cancelled less than 20% of the time. The problem for the traveller is that it's unpredictable.

From the airline's point of view, it doesn't always make economic sense to make the maximum effort to get passengers on "ghost flights". That's why it's not always easy or even possible for potential travellers to get places on them.

[jiggery-pokery.livejournal.com]

Without prejudicing the outcome of this question (and you may note that I asked a similar question a while back (http://fivemack.livejournal.com/190735.html?thread=861967#t861967)) is the radiative forcing concept generally accepted by the scientific community at large? Is it criticised and found to stand up to criticism?

[monkeyhands.livejournal.com]

I'm not sure exactly what you mean by your question. Are you asking about radiative forcing in general, or radiative forcing as it applies to aviation emissions?

Radiative forcing in general is just the term that scientists, specifically the IPCC, use to mean a change in the radiative energy balance of the Earth's climate. As such, there's no real debate.

As for the radiative forcing of climate change through aircraft emissions, the IPCC agree that the Radiative Forcing Index for aircraft was about 2.7 in 1992 (apologies; I wrote 2.8 before because I was talking off the top of my head). Nobody knows what the RFI of travel will be in the future because it depends on technological advances. So the IPCC have come up with a set of possible scenarios. The RFI of air travel in 2050 could be anything from 2.2 to 3.4, according to the IPCC. But they believe that we need to do a lot more research in this area.

So, the short answer to your question is: radiative forcing in general is a universally accepted scientific concept. The radiative forcing of aircraft emissions is also accepted by mainstream science, but more research is needed to verify the current figures and get a clearer idea of what it will be in the future.

[jiggery-pokery.livejournal.com]

*nods* Thank you.

[monkeyhands.livejournal.com]

I'm glad if I made it clearer, and sorry that I missed the question first time round.

I'm not actually a scientist, just someone who thinks that the science of climate change should be better-known by laypeople.