Hacker News Reader

Comment by mikeash | Hacker News Reader

I don't understand the emphasis on air travel I frequently see in these discussions.

Passenger planes are much more fuel efficient per passenger-mile than single-occupancy cars. Most people drive far more miles alone each year than they travel by plane. It makes no sense to me to criticize someone for flying a couple thousand miles at ~100MPG when the average American drives 12,000 miles per year at ~25MPG.

Beyond that, I don't see how refraining from individually polluting activities will help to enact the laws and treaties we need to make a real difference. It's a collective action problem, and those aren't solved by having individuals with strong beliefs alter their own habits to match what they want, they're solved by having individuals with strong beliefs convince everybody to change their habits.

View on HN

The one that gets me is the suggestion that direct flights are more efficient. Sure, if you go from New York to Los Angeles, but it wouldn't make sense if you were headed to a smaller city away from a major centre.

With millions to be saved, I'm sure airlines do a decent job of working out the most efficient combination of large direct flights and smaller commuter planes. I don't think a 3/4 empty 767 to Fargo is the way to go.

If you want to take it to an extreme, imagine if the post office only delivered your mail point-to-point in the interest of efficiency.

I actually wrote a Mac screensaver with this theme: https://www.mikeash.com/software/chemicalburn/

It shows the transportation networks that arise if you assume that the link between two points gets better as more traffic uses it. It has different curves for the improvement which produce different patterns. Many of them produce the familiar hub-and-spoke model, all without any such notion in the underlying code.

Passenger planes are much more fuel efficient per passenger-mile than single-occupancy cars.

Where did you get this idea from? Flying being more efficient than rolling doesn't fit with what little physics I know.

Do you have a better source than:

http://adl.stanford.edu/aa260/Lecture_Notes_files/transport_...

I would be genuinely interested if you have other references to transport fuel efficiency.

Just from general knowledge. You can verify it by googling "$AIRLINERMODEL passenger miles per gallon" for various aircraft types. Or Wikipedia has a good roundup:

https://en.wikipedia.org/wiki/Fuel_economy_in_aircraft

Typical values are 70+ PMPG, and 100+ isn't uncommon. (I just made up the PMPG acronym, so don't go trying to search with it.) The most efficient gasoline car you can buy today will do about 56MPG.

Flying isn't more efficient than rolling, but big is more efficient than small, and high is more efficient than low. Cars and airliners are massively different in ways beyond just rolling versus flying. Note that small aircraft definitely do not have this efficiency advantage. A 737 gets to carry 180 or so people at a time and travel at 35,000 feet, and that's a big win over a car carrying one person near sea level. Busses and trains win big over airliners, because they get the same scaling advantages without the disadvantage of having to use aerodynamic lift.

Compare flying versus not flying, not to cars.

For tens to hundreds of thousands of years, humans found ways to be happy where they were. Today people fly across the country to go to a party. Or to see the Great Barrier Reef before it disappears, due to pollution.

Yet they don't know their neighbors.

My goal is to help people improve their lives living less wasteful lives, not deprive themselves. It takes changing mental models, which is a big part of what leaders do.

For tens to hundreds of thousands of years, humans found ways to be happy without cars, electricity, or central heating too, so why does it seem like air travel is always the poster boy for "you're so hypocritical about fighting climate change" statements?

Because there is not much a difference in going to Australia or to the next big coast if you are staying in your hotel anyways. Many people go on vacation trips without any reason but showing off to friends how well they get around. Going without electricity or central heating on the other hand has a big impact on your every day life (and even there we are advocating it like powering off devices and light when you leave the room, cooling down the temperature at night, when you are away and also in general. It is just that for intercontinental flights there is most of the time no real reason but because you can. And thats no reason at all.

Seems like there must be a difference, because people pay substantial premiums for it. Air travel isn't cheap, and the cost correlates fairly well with the CO2 emissions produced, so if people are going to Australia instead of the next big coast they must think it's worth a decent amount.

Maybe it's not worth enough considering the damage done to the climate, but the only way to get people in general to care is to bake that cost into the price they pay. Telling them that going to Delaware is as good as going to Australia will just make them think you're a nut.

Going without electricity and central heating would be huge, but reducing your electricity consumption and turning your thermostat down a couple of degrees is a pretty small sacrifice, and can easily save more CO2 than a typical person's airline travel.

And yes, there are plenty of people advocating for conservation in every imaginable area. But it seems like air travel is the first and often only target for complaints of hypocrisy. I haven't seen anyone say, "How many people advocating for action on climate change eat beef, or had fruit from another continent for breakfast?"

Same thing happens when people see a city bus spewing black smoke from it's exhaust pipe, without realizing that that bus is currently taking the place of 20 or more cars.

Not the bus that roars past my window at midnight every night.

That´s true. The bus at night is (or should be) there to prevent drunk drivers.

Reply on news.ycombinator.com