3% is a significant portion of emissions. I don’t know why you keep insinuating that it is not.
Commercial flight is not energy efficient. You said it yourself: it is time efficient. You don’t get to constantly repeat their “suburban” argument and then ignore that the suburban - one of the least energy-efficient passenger vehicles - is considerably more energy efficient than air travel. You will burn less fuel per mile per person in the suburban than in the airplane.
Reducing travel expectations has a massive effect. Changing societal expectations from 2000-mile trips to 200-mile trips reduces a 3% problem to a 0.3% problem.
Electric vehicles are now viable options for most personal and commercial vehicles. Even heavy-haul has viable electric options coming online. Natural gas produces about 1/3 the carbon output as an energy equivalent amount of jet fuel, and has replaced diesel in the majority of metro bus fleets.
The state of alternative energy use in aviation is in its infancy: no options to date are remotely viable replacements for kerosene-based jet fuel. As absolute carbon use declines in the ground transport fleet, the relative proportion of carbon use rises in the aviation sector. Every other sector is primed to reduce emissions. Lagging behind is the aviation sector. That 3% number has nowhere to go but up.
3% is a significant portion of emissions. I don’t know why you keep insinuating that it is not.
I’m not insinuating anything, much less that. I’m simply saying that there are more impactful ways to make a difference and, relative to the other options, that 3% is also more difficult to change. It’s not realistic to ask people not to travel when we live in a world where families can span continents especially when there are easier ways to make a bigger difference.
is considerably more energy efficient than air travel.
This is simply not true. In the link that the “suburban” commenter sent, it says that planes have an average fuel/distance/passenger ratio of 67mpg per passenger. There is not a single car available that gets 67 mpg much less per passenger. The Toyota Prius is a hybrid (so its rating isn’t even based completely on burning fuel) and it gets 52mpg. And most commutes average 1.2 people per trip with an average of 4 trips per day. It’s not even close.
That 3% number has nowhere to go but up.
You’re only proving my point. When those other sectors get to the point where their emissions are a single digit percentage lower than 5 of the overall total, we can talk about whether we should keep working on those or switch to airplanes.
There is not a single car available that gets 67 mpg much less per passenger.
A suburban gets 27mpg highway. A suburban with just 3 people on board gets 81mpg per passenger.
67 mpg per passenger is terrible mileage for a mass transit vehicle. A bus gets about 6mpg, but typically carries 30 to 50 people. That’s 180 to 300mpg per passenger.
I reject your “1.2 people per commute” argument because we aren’t talking about commuting. We’re talking about long-distance trips.
No, aviation is one of the largest sectors left that has made no significant headway on eliminating emissions. Every other sector has a solid plan for shifting away from oil that they are in the long process of executing.
The airlines are still at the stage of trying to optimize their use of fossil fuels, not replacing fossil fuels with renewables. They are getting good at making bigger, more efficient engines and airframes, but they have no feasible approach to actually switch away. The energy density of oil is just too high to readily replace.
Until they can actually make some headway, we should absolutely be discouraging long-distance travel in general, and aviation travel in particular.
“The main findings are that to make driving less energy intensive than flying, the fuel economy of the entire fleet of light-duty vehicles would have to improve from the current 21.5 mpg to at least 33.8 mpg, or vehicle load would have to increase from the current 1.38 persons to at least 2.3 persons.”
You can reject my argument but that just makes you wrong. Even the non-commute average load is still not enough to make the average long-distance trip more fuel efficient.
no significant headway
Also wrong.
“A new report from the University of Michigan’s Transportation Research Institute shows that flying has become 74% more efficient per passenger since 1970 while driving gained only 17% efficiency per passenger. In fact, the average plane trip has been more fuel efficient than the average car trip since as far back as 2000, according to their calculations.”
So it makes sense to divide planes mpg by passenger but not car mpg by passenger? Because the 67mpg you’re quoting is per passenger.
A 4 passenger car that gets 20mpg, what’s the mpg per passenger? Two ways to get to the result: fuel used is divided between passengers so each passenger uses 25% of the fuel, so 20mpg/25% = 80mpg per passenger OR even simpler, 20 mpg x 4 passengers. The result is the same. For planes, using my example from another comment, 82mpg/passenger, 388 passengers, 82/388 = 0.21mpg/passenger with one passenger.
Don’t tell me you truly believe that planes consume 67mpg by themselves because then you’ll have to explain why they need to cary thousands of gallons of fuel… (13k gallons for a 777)
Again, you’re comparing the average number of passengers for all road trips vs the average number of passengers for all airline trips, but the purpose of both isn’t the same and just because someone took a plane to go somewhere doesn’t mean they won’t be taking their car to work. Compare both travels for the same purpose (in this discussion, vacations) and people don’t tend to go on vacation alone, that increases the number of passengers in the car, they don’t tend to go as far in their car so that also lowers the amount of fuel used for the vacation.
For all purposes of travel, planes are more efficient. The longer a plane trip is the more efficient it is because the plane loses weight as you travel, not the other way around.
How can you ignore the multiple sources I’ve provided to still get the math wrong? Flying is more fuel efficient than cars. The only way you can make it less efficient is to limit the car rides to only rides that have 3+ passengers and only those that are multiple hundreds of miles in distance. That limits the trips we’re talking about to such a small percentage of auto travel that making progress in that specific area renders it meaningless. The majority of the carbon impact of driving comes from all the other usage. Airline travel has been more efficient than road travel since the start of the millennium.
For all purposes of travel, planes are more efficient. The longer a plane trip is *the more efficient it is* because the plane loses weight as you travel, not the other way around.
The 67mpg/passenger number from the source I provided is based on trillions of miles traveled, don’t you think that’s taken into consideration?
I don’t get the math wrong, you interpret the data incorrectly and think that planes get 67mpg/vehicle instead of 67mpg/passenger and you compare car rides to work to long distance air travel instead of comparing leisure travel for both in which case cars are much more likely to be used for multi passenger travel.
You need to recheck your math. It doesn’t make sense to divide the consumption by plane but multiply by car.
The math I used is an estimation, but a reasonable one. I didn’t divide by one and multiply by the other. I converted automobile MPG to MPG per passenger mile, by assuming various numbers of passengers.
If I burn a gallon of gas in a suburban, the suburban moves 27 miles. If I have 3 people on board, each moving 27 miles, the suburban has produces 81 passenger miles on a gallon of gas. That is 81 miles per gallon per passenger, or 81 passenger-miles per gallon.
If I put 3 more people on board, I produce 162 passenger miles on that same gallon of gas. The vehicle travels 27 miles, 6 passengers each travel 27 miles, passengers travel a total of 162 miles. One gallon of gas is burned. 162 passenger-miles per gallon, or mpg per person. The more people on board, the more efficiently the vehicle produces passenger-miles. (Obviously, the actual vehicle economy would fall slightly as I add weight, but the efficiency gains of carpooling would greatly exceed the negligible losses due to additional passenger weight)
I don’t know how many people were on the plane for the figures you provided. If I assume it was 200 people, then the plane’s economy is 67mpg/200, or 0.335mpg. If I assume 100 people, the plane’s economy is 0.67mpg. If I assume 67 people, the economy is 1mpg. All of these numbers are reasonable for jets capable of carrying a corresponding number of passengers.
The takeaway is that the fuel economy of flight is terrible compared to any other form of mass transit. It’s only when we factor in the value of time that flight becomes remotely reasonable.
And I stand by my “no headway” claim, because I was careful to specify my meaning. There are viable options for transportation that do not rely on fossil fuels. Electric cars, electric trains, electric trolleys, electric busses are all in commercial use today. The use of those vehicles is rising rapidly.
There are no commercially viable electric aircraft in the skies today, and no commercially viable alternatives to petroleum-based aviation fuel. Yes, the efficiency of those fossil fuels has increased, but no viable alternative is currently available, nor slated to be available in the near future.
The math I used is an estimation, but a reasonable one.
No, it’s not. You’re taking the fuel economy of a flight based on the average number of passengers but the fuel economy of a car based on a specific number you picked that makes your point despite it being a rare occurrence. If you compared apples to apples and calculated both based on the average passenger count, you wouldn’t get the same amount. The only way your point stands is if you only factor in trips that are greater than 200km with 3+ passengers - something that would account for 5% of all automotive usage and wouldn’t make a measurable difference in the total amount of emissions from cars.
The takeaway is that the fuel economy of flight is terrible compared to any other form of mass transit. It’s only when we factor in the value of time that flight becomes remotely reasonable.
Except that no one was comparing airplanes to mass transit and, even if they were, this is not true unless you restrict it to a very, very narrow set of parameters. Buses can’t swim across oceans. Trains can’t either. There’s no practical alternative in many situations. My point, from the beginning, has been that there are other sectors who produce more emissions and are easier to fix than the emissions that airlines have. Unless we get those in-line first, there’s no point on focusing on aircraft and especially not in the context of going back to thinking like in the 1900s where people just don’t see their families.
Electric cars, electric trains, electric trolleys, electric busses are all in commercial use today.
And are nowhere near prevalent enough to offset the emissions of cars in use today to make them emit less than airplanes or make them more fuel efficient than airplanes. Unless every ride has 3+ passengers, what you’re saying is simply not true.
No, it’s not. You’re taking the fuel economy of a flight based on the average number of passengers but the fuel economy of a car based on a specific number you picked that makes your point
As are you.
despite it being a rare occurrence.
There is no justification for your assumed average of 1.2 people per trip. You’re comparing “commutes” to things like “vacations”. I don’t take the wife and 4 kids with me to work; I do take them on vacation.
Even if we do assume a single rider, you don’t get to automatically assume “car”. An airplane is a mass-transit vehicle. A bus gives 180 to 300 MPG per passenger mile, and a train can be well over a thousand.
But we’re getting away from the point: whether by bus, car, train, plane, or even bicycle powered by a rider who consumes oxygen and expels CO2, the lowest level of emissions are produced when the trip is eliminated entirely, and the second lowest are when a long trip is replaced with a short trip. We need to focus on reducing travel in general.
No, I’m not. Stop lying. I’m taking the average for both because that’s the only way to determine which is more fuel efficient and which sector has the most opportunity for a change.
You’re comparing “commutes”
No, I’m not. More lies. I used commutes initially because that was the most common usage for a car by a landslide which is the same thing I did for air travel. You weren’t ok with that so I used the more general number and took the total average for all types of rides in a car with any number of passengers at all distances. That number is 1.3 passengers per ride. Anything less than, taking a subsection of the rides to narrow it down to only rides with 3+ passengers and only for “vacations” or whatever other nonsense constraints you want to put on it, only reduces the total available impact since rides with 3+ passengers are already an extremely small percentage of rides in a car and “vacation travel” is an even smaller portion than that.
you don’t get to automatically assume “car”
I didn’t. You guys used the example of a suburban. Emissions figures separate out mass transit from personal travel because they’re not comparable and mass transit has less opportunity for impact since it’s already the most sustainable method of transportation.
the lowest level of emissions are produced when the trip is eliminated entirely, and the second lowest are when a long trip is replaced with a short trip
A complete straw man. If people need to get to a destination, going on a shorter trip is meaningless as is eliminating the trip. The most impactful changes are those that have the highest ROI in terms of barriers and resources. Airplanes ain’t that.
There are loads of good e fuels now with various projects coming on line to start supplying them commercially.
When using e fuels flying is far better for the environment than a train, especially when track maintenance and etc are factored in.
But beyond technical stuff, I don’t know if you’re a secret agent of the captain planet baddies and if so then great work on the talking points, if there’s one way to turn people away from green issues it’s too tell them they can’t have a holiday or travel to see their parents at Christmas.
Yeah, this person is delusional. COVID basically proved that telling people that they can’t have parties indoors wasn’t even possible. This guy thinks that telling people they can’t travel to see their families unless they live within a 200km radius and they make the trip by car is a realistic solution.
3% is a significant portion of emissions. I don’t know why you keep insinuating that it is not.
Commercial flight is not energy efficient. You said it yourself: it is time efficient. You don’t get to constantly repeat their “suburban” argument and then ignore that the suburban - one of the least energy-efficient passenger vehicles - is considerably more energy efficient than air travel. You will burn less fuel per mile per person in the suburban than in the airplane.
Reducing travel expectations has a massive effect. Changing societal expectations from 2000-mile trips to 200-mile trips reduces a 3% problem to a 0.3% problem.
Electric vehicles are now viable options for most personal and commercial vehicles. Even heavy-haul has viable electric options coming online. Natural gas produces about 1/3 the carbon output as an energy equivalent amount of jet fuel, and has replaced diesel in the majority of metro bus fleets.
The state of alternative energy use in aviation is in its infancy: no options to date are remotely viable replacements for kerosene-based jet fuel. As absolute carbon use declines in the ground transport fleet, the relative proportion of carbon use rises in the aviation sector. Every other sector is primed to reduce emissions. Lagging behind is the aviation sector. That 3% number has nowhere to go but up.
I’m not insinuating anything, much less that. I’m simply saying that there are more impactful ways to make a difference and, relative to the other options, that 3% is also more difficult to change. It’s not realistic to ask people not to travel when we live in a world where families can span continents especially when there are easier ways to make a bigger difference.
This is simply not true. In the link that the “suburban” commenter sent, it says that planes have an average fuel/distance/passenger ratio of 67mpg per passenger. There is not a single car available that gets 67 mpg much less per passenger. The Toyota Prius is a hybrid (so its rating isn’t even based completely on burning fuel) and it gets 52mpg. And most commutes average 1.2 people per trip with an average of 4 trips per day. It’s not even close.
You’re only proving my point. When those other sectors get to the point where their emissions are a single digit percentage lower than 5 of the overall total, we can talk about whether we should keep working on those or switch to airplanes.
A suburban gets 27mpg highway. A suburban with just 3 people on board gets 81mpg per passenger.
67 mpg per passenger is terrible mileage for a mass transit vehicle. A bus gets about 6mpg, but typically carries 30 to 50 people. That’s 180 to 300mpg per passenger.
I reject your “1.2 people per commute” argument because we aren’t talking about commuting. We’re talking about long-distance trips.
No, aviation is one of the largest sectors left that has made no significant headway on eliminating emissions. Every other sector has a solid plan for shifting away from oil that they are in the long process of executing.
The airlines are still at the stage of trying to optimize their use of fossil fuels, not replacing fossil fuels with renewables. They are getting good at making bigger, more efficient engines and airframes, but they have no feasible approach to actually switch away. The energy density of oil is just too high to readily replace.
Until they can actually make some headway, we should absolutely be discouraging long-distance travel in general, and aviation travel in particular.
You need to recheck your math. It doesn’t make sense to divide the consumption by plane but multiply by car.
https://yaleclimateconnections.org/2015/09/evolving-climate-math-of-flying-vs-driving/ https://sustainableamerica.org/blog/flying-or-driving-which-is-more-efficient/ http://websites.umich.edu/~umtriswt/PDF/UMTRI-2014-2_Abstract_English.pdf
“The main findings are that to make driving less energy intensive than flying, the fuel economy of the entire fleet of light-duty vehicles would have to improve from the current 21.5 mpg to at least 33.8 mpg, or vehicle load would have to increase from the current 1.38 persons to at least 2.3 persons.”
You can reject my argument but that just makes you wrong. Even the non-commute average load is still not enough to make the average long-distance trip more fuel efficient.
Also wrong.
“A new report from the University of Michigan’s Transportation Research Institute shows that flying has become 74% more efficient per passenger since 1970 while driving gained only 17% efficiency per passenger. In fact, the average plane trip has been more fuel efficient than the average car trip since as far back as 2000, according to their calculations.”
You’re talking out of your ass.
So it makes sense to divide planes mpg by passenger but not car mpg by passenger? Because the 67mpg you’re quoting is per passenger.
A 4 passenger car that gets 20mpg, what’s the mpg per passenger? Two ways to get to the result: fuel used is divided between passengers so each passenger uses 25% of the fuel, so 20mpg/25% = 80mpg per passenger OR even simpler, 20 mpg x 4 passengers. The result is the same. For planes, using my example from another comment, 82mpg/passenger, 388 passengers, 82/388 = 0.21mpg/passenger with one passenger.
Don’t tell me you truly believe that planes consume 67mpg by themselves because then you’ll have to explain why they need to cary thousands of gallons of fuel… (13k gallons for a 777)
Again, you’re comparing the average number of passengers for all road trips vs the average number of passengers for all airline trips, but the purpose of both isn’t the same and just because someone took a plane to go somewhere doesn’t mean they won’t be taking their car to work. Compare both travels for the same purpose (in this discussion, vacations) and people don’t tend to go on vacation alone, that increases the number of passengers in the car, they don’t tend to go as far in their car so that also lowers the amount of fuel used for the vacation.
For all purposes of travel, planes are more efficient. The longer a plane trip is the more efficient it is because the plane loses weight as you travel, not the other way around.
How can you ignore the multiple sources I’ve provided to still get the math wrong? Flying is more fuel efficient than cars. The only way you can make it less efficient is to limit the car rides to only rides that have 3+ passengers and only those that are multiple hundreds of miles in distance. That limits the trips we’re talking about to such a small percentage of auto travel that making progress in that specific area renders it meaningless. The majority of the carbon impact of driving comes from all the other usage. Airline travel has been more efficient than road travel since the start of the millennium.
For all purposes of travel, planes are more efficient. The longer a plane trip is *the more efficient it is* because the plane loses weight as you travel, not the other way around.The 67mpg/passenger number from the source I provided is based on trillions of miles traveled, don’t you think that’s taken into consideration?
I don’t get the math wrong, you interpret the data incorrectly and think that planes get 67mpg/vehicle instead of 67mpg/passenger and you compare car rides to work to long distance air travel instead of comparing leisure travel for both in which case cars are much more likely to be used for multi passenger travel.
No I don’t. I have never said that anywhere.
Stop lying and stop moving the goalposts.
Yes you do, you keep arguing as if it was the case!
The math I used is an estimation, but a reasonable one. I didn’t divide by one and multiply by the other. I converted automobile MPG to MPG per passenger mile, by assuming various numbers of passengers.
If I burn a gallon of gas in a suburban, the suburban moves 27 miles. If I have 3 people on board, each moving 27 miles, the suburban has produces 81 passenger miles on a gallon of gas. That is 81 miles per gallon per passenger, or 81 passenger-miles per gallon.
If I put 3 more people on board, I produce 162 passenger miles on that same gallon of gas. The vehicle travels 27 miles, 6 passengers each travel 27 miles, passengers travel a total of 162 miles. One gallon of gas is burned. 162 passenger-miles per gallon, or mpg per person. The more people on board, the more efficiently the vehicle produces passenger-miles. (Obviously, the actual vehicle economy would fall slightly as I add weight, but the efficiency gains of carpooling would greatly exceed the negligible losses due to additional passenger weight)
I don’t know how many people were on the plane for the figures you provided. If I assume it was 200 people, then the plane’s economy is 67mpg/200, or 0.335mpg. If I assume 100 people, the plane’s economy is 0.67mpg. If I assume 67 people, the economy is 1mpg. All of these numbers are reasonable for jets capable of carrying a corresponding number of passengers.
The takeaway is that the fuel economy of flight is terrible compared to any other form of mass transit. It’s only when we factor in the value of time that flight becomes remotely reasonable.
And I stand by my “no headway” claim, because I was careful to specify my meaning. There are viable options for transportation that do not rely on fossil fuels. Electric cars, electric trains, electric trolleys, electric busses are all in commercial use today. The use of those vehicles is rising rapidly.
There are no commercially viable electric aircraft in the skies today, and no commercially viable alternatives to petroleum-based aviation fuel. Yes, the efficiency of those fossil fuels has increased, but no viable alternative is currently available, nor slated to be available in the near future.
No, it’s not. You’re taking the fuel economy of a flight based on the average number of passengers but the fuel economy of a car based on a specific number you picked that makes your point despite it being a rare occurrence. If you compared apples to apples and calculated both based on the average passenger count, you wouldn’t get the same amount. The only way your point stands is if you only factor in trips that are greater than 200km with 3+ passengers - something that would account for 5% of all automotive usage and wouldn’t make a measurable difference in the total amount of emissions from cars.
Except that no one was comparing airplanes to mass transit and, even if they were, this is not true unless you restrict it to a very, very narrow set of parameters. Buses can’t swim across oceans. Trains can’t either. There’s no practical alternative in many situations. My point, from the beginning, has been that there are other sectors who produce more emissions and are easier to fix than the emissions that airlines have. Unless we get those in-line first, there’s no point on focusing on aircraft and especially not in the context of going back to thinking like in the 1900s where people just don’t see their families.
And are nowhere near prevalent enough to offset the emissions of cars in use today to make them emit less than airplanes or make them more fuel efficient than airplanes. Unless every ride has 3+ passengers, what you’re saying is simply not true.
As are you.
There is no justification for your assumed average of 1.2 people per trip. You’re comparing “commutes” to things like “vacations”. I don’t take the wife and 4 kids with me to work; I do take them on vacation.
Even if we do assume a single rider, you don’t get to automatically assume “car”. An airplane is a mass-transit vehicle. A bus gives 180 to 300 MPG per passenger mile, and a train can be well over a thousand.
But we’re getting away from the point: whether by bus, car, train, plane, or even bicycle powered by a rider who consumes oxygen and expels CO2, the lowest level of emissions are produced when the trip is eliminated entirely, and the second lowest are when a long trip is replaced with a short trip. We need to focus on reducing travel in general.
No, I’m not. Stop lying. I’m taking the average for both because that’s the only way to determine which is more fuel efficient and which sector has the most opportunity for a change.
No, I’m not. More lies. I used commutes initially because that was the most common usage for a car by a landslide which is the same thing I did for air travel. You weren’t ok with that so I used the more general number and took the total average for all types of rides in a car with any number of passengers at all distances. That number is 1.3 passengers per ride. Anything less than, taking a subsection of the rides to narrow it down to only rides with 3+ passengers and only for “vacations” or whatever other nonsense constraints you want to put on it, only reduces the total available impact since rides with 3+ passengers are already an extremely small percentage of rides in a car and “vacation travel” is an even smaller portion than that.
I didn’t. You guys used the example of a suburban. Emissions figures separate out mass transit from personal travel because they’re not comparable and mass transit has less opportunity for impact since it’s already the most sustainable method of transportation.
A complete straw man. If people need to get to a destination, going on a shorter trip is meaningless as is eliminating the trip. The most impactful changes are those that have the highest ROI in terms of barriers and resources. Airplanes ain’t that.
There are loads of good e fuels now with various projects coming on line to start supplying them commercially.
When using e fuels flying is far better for the environment than a train, especially when track maintenance and etc are factored in.
But beyond technical stuff, I don’t know if you’re a secret agent of the captain planet baddies and if so then great work on the talking points, if there’s one way to turn people away from green issues it’s too tell them they can’t have a holiday or travel to see their parents at Christmas.
Yeah, this person is delusional. COVID basically proved that telling people that they can’t have parties indoors wasn’t even possible. This guy thinks that telling people they can’t travel to see their families unless they live within a 200km radius and they make the trip by car is a realistic solution.