Will we ever fly supersonically over land?(newyorker.com)
newyorker.com
Will we ever fly supersonically over land?
https://www.newyorker.com/tech/annals-of-technology/will-we-ever-fly-supersonically-over-land
219 comments
https://archive.is/Ut9az
> These studies, along with tens of thousands of claims against the Air Force for property damage—horses and turkeys had supposedly died or gone insane—led the F.A.A. to ban civil overland supersonic flight, in 1973.
There was also a political part involved. The Concorde was a British-French creation, not a Boeing. Had there been a Boeing supersonic passenger plane first there would probably have been different FAA rules. Especially because military supersonic flight happens every day over US land, was never banned, and causes the same boom.
There was also a political part involved. The Concorde was a British-French creation, not a Boeing. Had there been a Boeing supersonic passenger plane first there would probably have been different FAA rules. Especially because military supersonic flight happens every day over US land, was never banned, and causes the same boom.
Military supersonic flight over land in the US only happens over unpopulated areas. Ie, parts of Idaho, Nevada desert etc. Most supersonic training is conducted over the oceans, eg >15nm from the east coast.
Military supersonic flight over land in the US is supposed to only happen over unpopulated areas. Having lived near a coastline (~1 mile from the shoreline) along a military flight path, I know they occasionally went a little early.
Depending on the jet, accidental supersonic can be easy/common, or rare. (eg a strike eagle with the older engines won't go super unless you're trying)
How loud was it and how often did you experience it?
F-104 going supersonic at something like 500ft or slightly lower within less than a mile feels like a full body slap which makes the parts of your clothing which are not tight flutter. Anything a few thousands feet up is still very loud but doesn't do the slapping and fluttering anymore. Anything a few 10.000 feet can still be very loud. Though it varies. Don't know on what it depends exactly. Had 4 in row making nice contrails high up, rather soft. Had single ones, also high up, making a contrail, banging loud and sharp, thinking why was that? Those are all memories from the 80ies. Can't remember when I heard the last supersonic boom anymore. Has to be early 90ies. Today I laugh when I read about people calling the emergency services when they heard one ;-)
They did it near London once by in error. One little Typhoon can produce an unbelievably powerful sonic boom. I felt it as a loud crack/thump on my roof. Now, imagine a Concorde going supersonic...
If I recall correctly. The recent examples of Typhoons going super sonic over London were QRA aircraft hammering it down the country to pick up suspicious aircraft. In some of those cases they are allowed do it
It happens in the Lake District and Wales reasonably often. Often the pilot/crew will go out and apologize to a farmer. Sometimes livestock allegedly die, although I'm not sure what the mechanism is.
That mechanism is trying to get compensated for dead live stock and pulling straws.
Thunder is a sonic boom. It’s like saying thunder killed a cow.
very loud sounds can panic/shock animals and if it's too much for them, they die.
Well, in that case, when will we start jailing bikers with loud exhausts for the deaths of old people from heart attacks?
I dream of a day when light and noise pollution are taken seriously. Its exhausting walking beside a busy road with the roar of traffic. You see the birds don't even bother to try and sing anymore. They are just silent and isolated until they get further away. Visual pollution from advertising would be great to curb as well.
Many places do regulate the noise levels of exhausts, which seems a bit more appropriate and less punitive than permitting any exhaust and hoping people don't die as a result. The penalties for noncompliance are obviously not as high as jail time, but at least to me, (among other things) there is an element of premeditation or willfulness missing in these deaths.
God that would honestly be a dream come true actually
Is there documented proof of this actually happening?
Rural person here from Wales where sonic booms from military aircraft were moderately common.
Animals panic when they hear the boom: they tend to stampede, fall off cliffs, break legs, trample each other, lambs get separated, break through hedges and into traffic.
The booms were severe enough to occassionally shatter the Royal Doulton in the house, much to my mother's disgust.
Animals panic when they hear the boom: they tend to stampede, fall off cliffs, break legs, trample each other, lambs get separated, break through hedges and into traffic.
The booms were severe enough to occassionally shatter the Royal Doulton in the house, much to my mother's disgust.
Best childhood memories are from doing walks in the Lakes and having jets zip past in the valleys below. Insanely close, too — I distinctly remember seeing the pilot’s visor and making out white text on the side of the aircraft.
Is the Lake District the infamous “Mach loop”?
No - the Mach Loop is in Wales. Although as the jet flys, they're not far off - so it's common to do lowfly training missions that include both. The loop has a number of aviation enthusiasts who reside there. They'll hear jet noise (or listen on the radio...), then call their friends, get out of their houses, and watch / snap pics of the planes.
I've had similar in Wales. I once got the shock of my life when a jet roared probably not more then 100 foot over my head.
Didn't have a decibel meter, but pretty loud, rattled the house and windows. Not as bad as someone using tannerite, though it might just be that the tannerite is a relatively recent experience and the sonic booms were a while ago.
Indeed it was political. IMHO if a US supersonic commercial plane comes into service without an Airbus counterpart, it won't have access to the European skies. At least not the over french territory. The industry is still very salty that the Concorde market was taken from under them.
Europe banned supersonic commercial flights over the continent 2 years before the US did.
Whilst this was political to some extent the politics were very much local, as in people don’t want to hear booms.
Whilst this was political to some extent the politics were very much local, as in people don’t want to hear booms.
Also, shattered windows. A boom can easily smash windows.
Not that easily. Even with a fighter at 500 ft above, Mythbusters couldn't break windows. The Oklahoma tests had eight booms a day using very large aircraft. It took months before windows broke.
Long term wear and tear is a legitimate concern.
I’d be pisses if jets flying overheard broke my windows once every five years.
I’d be pisses if jets flying overheard broke my windows once every five years.
The Space Shuttle's sonic boom broke one of my bay windows when I was living in Orlando. Mythbusters was an entertainment TV show, I wouldn't extend their results to real life.
Especially 100 year + old buildings with original glass.
not really the same, fighters are quite smaller than airliners.
Less than you might think. Wingspan Concord 25.6m vs F-22 13.56m. Maximum takeoff weight Concord 185,000kg vs F-22 60,000kg.
Expanding that to all supersonic military aircraft and the Rockwell B-1 Lancer has a higher maximum takeoff weight than the concord. It’s a loud and heavy beast.
Expanding that to all supersonic military aircraft and the Rockwell B-1 Lancer has a higher maximum takeoff weight than the concord. It’s a loud and heavy beast.
I wonder if the comparison would be more frontal area than weight?
They might be smaller, but the boom is quite startling; I certainly wouldn't want to endure them regularly. I know because booms from fighters were common during my trip to West Germany in 1970. (I'm relying on what locals told my parents as to the source of the booms: I never saw a plane.) I've never heard a sonic boom in my 60 years of living in the US.
Rural Alabama had them semi-frequently in the late 70s and early 80s. Not sure where the fighters came from, perhaps Maxwell AFB had a training wing at that time. As far as I know, it never broke anything but it sure would rattle your dental work.
You are correct. I clearly remember hearing sonic booms in Montgomery, AL in the early 70s.
I used to hear them all the time in Texas when I was a kid in the 70s. We were fairly close to an air force base and we'd be out in the yard on a bright sunny day when we'd hear a thunderclap, as if lightning had struck less than a mile away. We'd look up, see a contrail, and say "Oh." It never caused any damage; it was just surprising.
I heard them all the time near Vandenburg AFB in the 70's and early 80's. I don't remember when exactly I stopped hearing them.
I don't see why the boom energy has anything to do with the size of the aircraft producing it. It should only depend on the speed of the spike that produces the boom; typically the entire aircraft fits within the sonic boom cone produced by the nose spike when flying straight.
So I suppose an artillery shell, a jet fighter, and a Concorde should produce about the same amount of boom at the same speed of, say, 1.5 M, while flying by.
The engine sound of the aircraft, though, can add significantly to the noise in the wake of the boom cone. Those engines are not low-power or quiet.
So I suppose an artillery shell, a jet fighter, and a Concorde should produce about the same amount of boom at the same speed of, say, 1.5 M, while flying by.
The engine sound of the aircraft, though, can add significantly to the noise in the wake of the boom cone. Those engines are not low-power or quiet.
Why wouldn't size correlate with magnitude? A whip crack breaks the sound barrier, it doesn't shatter windows. Same with a bullet, which goes even faster.
You need both pressure level (voltage) and momentum (current) in order to stay strong over distances (shock waves diffuse over time) to break windows. Small, super fast things create large pressure differentials, big jets create more momentum.
You need both pressure level (voltage) and momentum (current) in order to stay strong over distances (shock waves diffuse over time) to break windows. Small, super fast things create large pressure differentials, big jets create more momentum.
Because the Mach cone produced by the leading edge/cone keeps most of the air from interacting with the aircraft behind it. It’s in the ‘wake’ as it were, though there may be multiple Mach cones or non-‘cone’ shaped ones depending on the shape of the aircraft.
This does cause some stability or handling issues for the aircraft.
The analogy re: voltage or amperage are spurious and just don’t apply here.
This does cause some stability or handling issues for the aircraft.
The analogy re: voltage or amperage are spurious and just don’t apply here.
Surely the air is still interacting with the airplane.
The shockwave generated by a body shaped like an acute cone is a (somewhat less acute) cone with the same apex. Inside the shock wave, the air gradually turns around to move parallel to the body, like so [0]. Each streamline that enters the shock structure keeps turning around, so each bit of air keeps feeling a force even after it passes through the original cone-shaped shock. In the case of a cone-shaped body, the interaction happens to create a single "straight" wave, but it's still generated by the entire surface of the cone, not just the sharp point of it.
As a rule of thumb, the magnitude of the sonic boom is proportional to the weight of the plane. That is because most of the interaction between the plane and the air is from the wing, it needs to continuously deflect down enough air to generate a lifting force. So the total boom has one contribution from the cross-section of the fuselage, and another from the wings, and the latter is determined by the weight.
[0] https://www.researchgate.net/profile/Richard-Benay/publicati...
The shockwave generated by a body shaped like an acute cone is a (somewhat less acute) cone with the same apex. Inside the shock wave, the air gradually turns around to move parallel to the body, like so [0]. Each streamline that enters the shock structure keeps turning around, so each bit of air keeps feeling a force even after it passes through the original cone-shaped shock. In the case of a cone-shaped body, the interaction happens to create a single "straight" wave, but it's still generated by the entire surface of the cone, not just the sharp point of it.
As a rule of thumb, the magnitude of the sonic boom is proportional to the weight of the plane. That is because most of the interaction between the plane and the air is from the wing, it needs to continuously deflect down enough air to generate a lifting force. So the total boom has one contribution from the cross-section of the fuselage, and another from the wings, and the latter is determined by the weight.
[0] https://www.researchgate.net/profile/Richard-Benay/publicati...
sub-sonic, trans-sonic, and supersonic aerodynamics are fundamentally different. You’re calling out some differences, but not covering others.
They are wildly, fundamentally different in behavior.
You’ll notice that supersonic aircraft have different airfoil shapes, different airframe shapes, and wildly different engine configurations because they don’t work the same way.
There is of course air behind the Mach cone, but it is much lower pressure, will often completely separate (airflow wise) from the airfoil shape in ways you would not expect, and the shockwaves/speed of propagation can cause bizarre pressure, lift, and drag issues. You can end up with massive vacuum where you previously had pressure, or pressure where you preciously had vacuum. Transonic flight or high angle of attack flight at supersonic speeds of course produces rapidly changing variations of all these effects.
[https://arc.aiaa.org/doi/abs/10.2514/8.1394?journalCode=jans]
Unlike subsonic flight, the air can’t “get out of the way” in time, leading to potentially catastrophic issues without careful design. Supersonic flight is better categorized as ‘shoving through slow air’ than flight.
What you’re referring to is not wrong - just doesn’t reflect the magnitude of the actual differences
They are wildly, fundamentally different in behavior.
You’ll notice that supersonic aircraft have different airfoil shapes, different airframe shapes, and wildly different engine configurations because they don’t work the same way.
There is of course air behind the Mach cone, but it is much lower pressure, will often completely separate (airflow wise) from the airfoil shape in ways you would not expect, and the shockwaves/speed of propagation can cause bizarre pressure, lift, and drag issues. You can end up with massive vacuum where you previously had pressure, or pressure where you preciously had vacuum. Transonic flight or high angle of attack flight at supersonic speeds of course produces rapidly changing variations of all these effects.
[https://arc.aiaa.org/doi/abs/10.2514/8.1394?journalCode=jans]
Unlike subsonic flight, the air can’t “get out of the way” in time, leading to potentially catastrophic issues without careful design. Supersonic flight is better categorized as ‘shoving through slow air’ than flight.
What you’re referring to is not wrong - just doesn’t reflect the magnitude of the actual differences
They will still use an enormous amount of fuel, carry fewer passengers, and heavily pollute the environment. I'm not too excited about the prospects.
But are they that much worse than private jets and helicopters on a per person level?
[deleted]
Flying, in-general, is inefficient unless it's a large, lifting body in ground effect.
Flying on a full or almost-full plane is more carbon efficient than driving solo.
And that's not taking into account the cost of the road networks we build and maintain to allow high volumes of vehicular traffic.
https://yaleclimateconnections.org/2015/09/evolving-climate-...
And that's not taking into account the cost of the road networks we build and maintain to allow high volumes of vehicular traffic.
https://yaleclimateconnections.org/2015/09/evolving-climate-...
> Flying on a full or almost-full plane is more carbon efficient than driving solo.
But how do they fare against trains, especially since trains can run on electricity? The mpg quoted in your article (21.6) also seems really low.
But how do they fare against trains, especially since trains can run on electricity? The mpg quoted in your article (21.6) also seems really low.
Oddly light rail in silicon valley uses more BTUs per passenger-mile than cars do. Of course that is caused by the fact that light rail has so few passengers (and the number has been falling even pre-covid).
>that's not taking into account the cost of the road networks we build and maintain
Well, why would you? Then you'd have to take into account the airports and the transportation networks to get to them...
Well, why would you? Then you'd have to take into account the airports and the transportation networks to get to them...
Please do so. Airports are nothing compares to just I80 across the US. There are a lot of other roads as well that we could downgrade if more people flew.
I think autonomous vehicles will help here eventually too. A lot of road maintenance is due to large semi-trucks. If those vehicles are operated autonomously, they can be programmed to drive more efficiently in regards to wear on the roads. Slower braking, slower speeds (since you don’t need stops for drivers to sleep to reach your destination in the same amount of time).
We’d also see a closure of many roadside stops since there are no longer people around to use those facilities.
We’d also see a closure of many roadside stops since there are no longer people around to use those facilities.
Road wear is caused by weight. Driving and braking slower won't make a significant difference.
Road damage is said to be proportional to the fourth power of axle weight [0]. The link to reference 14 on the article is dead but the internet archive has a copy of it at [1].
[0] https://en.wikipedia.org/wiki/Vehicle_weight#Importance
[1] https://web.archive.org/web/20150709151027/http://www.nvfnor...
[0] https://en.wikipedia.org/wiki/Vehicle_weight#Importance
[1] https://web.archive.org/web/20150709151027/http://www.nvfnor...
An autonomous vehicle can keep the tires to the same track within 3cm. So there is potential to build pavement just where wheels go and corners.
I don't believe it, but it is possible.
I don't believe it, but it is possible.
Might also enable more frequent but smaller trucks, which also would enable more point to point movement of goods and less of a hub and spoke model.
I would need more information to flesh out how you think my default assumptions (that indirect costs are approximately proportional to direct costs) should be revised.
Facts and logic are optional, but at least a quantitative assertion that's falsifiable would be a start.
Facts and logic are optional, but at least a quantitative assertion that's falsifiable would be a start.
> Flying on a full or almost-full plane is more carbon efficient than driving solo.
… in a fossil-fuel burning automobile. Do things changes with the rise of EVs?
… in a fossil-fuel burning automobile. Do things changes with the rise of EVs?
Depends on where the electricity is coming from, and debatable if you account for all the externalities in producing the batteries, solar cells for photovoltaics, rare earth mining for magnets, and countless other stuff for way more silicon needed to regulate all that stuff to work efficiently together. Be it for in vehicle control, or smart grid.
On a 737 jammed to the gills. Now do the numbers on an sst with 50 people.
[deleted]
Maybe one time we manage to use something similar while flying supersonic with https://en.wikipedia.org/wiki/Compression_lift
I’d be interested to see a breakdown in fuel/seat-mile. I bet air travel isn’t as inefficient as the millions of people traveling alone in a car every day to work.
The thing is most people don’t drive their car 4000 miles across the Atlantic for a meeting.
All overland passenger transport should be rail. Over the oceans I suppose we should strive for ships and dirigibles.
That said, I find it hard to believe that plane travel can be eradicated for e.g. diplomacy. And frankly, if frequent contract between the powerful different countries is needed to avoid e.g. world wars, it's is worth it.
In the short term, any carbon we can capture needs to go in back in ground and stay there. But once we have good good greenhouse gas levels, much of carbon capture tech can be reused to make biofuels. I guess we can reward ourselves with lots of supersonic air travel then.
That said, I find it hard to believe that plane travel can be eradicated for e.g. diplomacy. And frankly, if frequent contract between the powerful different countries is needed to avoid e.g. world wars, it's is worth it.
In the short term, any carbon we can capture needs to go in back in ground and stay there. But once we have good good greenhouse gas levels, much of carbon capture tech can be reused to make biofuels. I guess we can reward ourselves with lots of supersonic air travel then.
Air travel has a big PR problem, because somehow a lot of people think it's the absolute worst for the environment. While on many routes a car is worse in terms of CO2 emission per trip than a small to mid sized airliner if there are less than 3 people in the car. Similar for your suggestion that we should take ships over the ocean, because cruise ships are much more polluting per passenger mile than modern airliners.
Air travel is not a problem because the emissions per kilometer are that bad but because one can easily travel one or two orders of magnitude farther than one usually would.
Exactly. It's not like if you couldn't fly from Los Angeles to New York once a month - you would just drive by yourself - and produce the same amount of carbon.
You wouldn't produce any carbon, because you'd likely never make the trip!
You wouldn't produce any carbon, because you'd likely never make the trip!
Yes, this is why dealing with air is so tricky in economic terms, because "uninducing demand" does have more intrinsic downsides. Car -> rail is a mere political problem, once you get there it "unlocks" more travel so it is clearly economically good.
I guess thank god for 9/11 boosting security theater. Don't like all the other patriot act garbage, but the degree to which air travel is so awful really helps here.
I guess thank god for 9/11 boosting security theater. Don't like all the other patriot act garbage, but the degree to which air travel is so awful really helps here.
After 9/11 air travel plateaued for 3–4 years, then afterward rebounded to the original trend line (i.e. massively expanded, and continues to expand).
It doesn’t seem that all of the unpleasant security theater is enough to significantly deter people from flying.
It doesn’t seem that all of the unpleasant security theater is enough to significantly deter people from flying.
No one its own, but I think it would make a difference had we avoid hsr alternative.
So your preferred solution is to restrict the allowed travel radius of people, a bit like with medieval serfs?
Restrictions may not be needed. Remove subsidies and price in externalties.
Most people dont realise that aircraft industry and fsrming use special fuel and pay no tax on it. While it makes sence that we sibsidiae cost of food, it is less clear why we subsidise airlines
> While it makes sence that we sibsidiae cost of food
That's already a thorny subject given that most governments also subsidize food sources that are vastly inefficient and resource-intensive even in cases where reasonable alternatives exist. Meat/dairy producers are still the primary recipients of subsidies in the US and many other countries, at least in Europe.
This number distinguishes between fruit/vegetables and other products, although the article apparently suggests that the use of corn/soy in meat production makes this figure more relevant:
> According to recent studies, the U.S. government spends up to $38 billion each year to subsidize the meat and dairy industries, with less than one percent of that sum allocated to aiding the production of fruits and vegetables.
https://jia.sipa.columbia.edu/removing-meat-subsidy-our-cogn...
That's already a thorny subject given that most governments also subsidize food sources that are vastly inefficient and resource-intensive even in cases where reasonable alternatives exist. Meat/dairy producers are still the primary recipients of subsidies in the US and many other countries, at least in Europe.
This number distinguishes between fruit/vegetables and other products, although the article apparently suggests that the use of corn/soy in meat production makes this figure more relevant:
> According to recent studies, the U.S. government spends up to $38 billion each year to subsidize the meat and dairy industries, with less than one percent of that sum allocated to aiding the production of fruits and vegetables.
https://jia.sipa.columbia.edu/removing-meat-subsidy-our-cogn...
If intentions are the same then these still can be seen restrictions on mobility.
Maybe encourage more high speed rail instead?
What a rhetoric device.
Is your preferred solution to let people die in droves to a mass extinction ?
Is your preferred solution to let people die in droves to a mass extinction ?
My preferred solution is buttloads of nuclear, carbon neutral solutions to liquid fuel (e.g. pulling CH4 out of atmosphere with Sabatier) and general carbon capture.
While producing clean energy would be great, a significant share of our travel issues is related to land use.
Ok, but... airplanes use the least land?
Much like the difference in land use with or without cars is not simply roads and parkings, but also the horizontal development of cities rather than vertical, the land use involved by planes is not simply the airstrips. Among others, it is also all the land developed specifically for vacation in remote places. If you look at [1] for instance, this area would simply not be developed if planes were not a thing.
[1]: https://www.google.com/maps/@21.1715988,-86.8077681,1041m/da...
[1]: https://www.google.com/maps/@21.1715988,-86.8077681,1041m/da...
What is wrong with vacations in remote places?
What mass extinction? From climate change? Has the Intergovernmental Panel on Climate Change said that because I’ve never seen that as a scientific claim.
We are currently going through a well-documented extinction[1]. It's not recent in human terms, but it's been accelerating recently, with industrialization.
Climate change is not the only, nor the major cause in the current extinction, but it contributes. In a way, this is unfortunate: it would be easier to have only one problem.
The relevant body for scientific information is not the IPCC, but the IPBES [2]. Like the IPCC, it releases reports summarizing the situation and its causes [3].
[1]: https://en.wikipedia.org/wiki/Holocene_extinction
[2]: https://en.wikipedia.org/wiki/Intergovernmental_Science-Poli...
[3]: https://en.wikipedia.org/wiki/Global_Assessment_Report_on_Bi...
Climate change is not the only, nor the major cause in the current extinction, but it contributes. In a way, this is unfortunate: it would be easier to have only one problem.
The relevant body for scientific information is not the IPCC, but the IPBES [2]. Like the IPCC, it releases reports summarizing the situation and its causes [3].
[1]: https://en.wikipedia.org/wiki/Holocene_extinction
[2]: https://en.wikipedia.org/wiki/Intergovernmental_Science-Poli...
[3]: https://en.wikipedia.org/wiki/Global_Assessment_Report_on_Bi...
I don’t think it’s necessarily the commenter’s solution but it does seem to be the one the world is going all in on.
FreeSpeech(1)
Nobody in this thread has suggested that.
Someone has now: https://news.ycombinator.com/item?id=27725760
True, but when you start comparing denominators in absolute terms you would also conclude that not traveling at all is the far superior choice. And also, that anything emitter (say, a gas grill) that’s unrelated to travel has infinite emissions per kilometer.
And if we use your co2 per mile approach we can all conclude that a rocket is the way to travel.
People judge these things in terms of how much co2 is emitted by industry, companies, individuals etc. The particular mechanism of emissions is not that relevant. Air ambulance flights are treated differently to private jets carrying bankers.
People judge these things in terms of how much co2 is emitted by industry, companies, individuals etc. The particular mechanism of emissions is not that relevant. Air ambulance flights are treated differently to private jets carrying bankers.
Why is further travel, per se, the problem?
> While on many routes a car is worse in terms of CO2 emission per trip than a small to mid sized airliner if there are less than 3 people in the car.
Wow. I read that one plane trip can increase your carbon footprint by a greater magnitude than all your typical actions to reduce it.
Does anyone know where to find some data?
EDIT: Here's some data https://www.bbc.com/news/science-environment-49349566
https://theicct.org/blogs/staff/planes-trains-and-automobile...
Also, planes have other problems:
* cars can be powered by carbon-free energy. There's not much current prospect for planes.
* planes also do great harm from non-CO2 emissions: "The climate effect of non-CO2 emissions from aviation is much greater than the equivalent from other modes of transport, as these non-CO2 greenhouse gases formed at higher altitudes persist for longer than at the surface and also have a stronger warming potential"
Wow. I read that one plane trip can increase your carbon footprint by a greater magnitude than all your typical actions to reduce it.
Does anyone know where to find some data?
EDIT: Here's some data https://www.bbc.com/news/science-environment-49349566
https://theicct.org/blogs/staff/planes-trains-and-automobile...
Also, planes have other problems:
* cars can be powered by carbon-free energy. There's not much current prospect for planes.
* planes also do great harm from non-CO2 emissions: "The climate effect of non-CO2 emissions from aviation is much greater than the equivalent from other modes of transport, as these non-CO2 greenhouse gases formed at higher altitudes persist for longer than at the surface and also have a stronger warming potential"
Jet engines are pretty robust to fuel quality within broad ranges. Atmospheric CO2 to a carbon-neutral jet fuel is technically possible now. (I don’t think it competes economically with Jet-A/kerosene/diesel at the moment.)
> While on many routes a car is worse than a small to mid sized airliner if there are less than 3 people in the car.
I never said cars. Cars are terrible. I would not complained if passenger-only cars were banned everywhere.
> Similar for your suggestion that we should take ships over the ocean, because cruise ships are much more polluting per passenger mile than modern airliners.
There are alternatives like wind power + giant batteries. The fact that weight doesn't matter for ships so much (container ships are more efficient than rail, scaling up is equivalent to shrinking the viscosity of water) opens a lot of doors.
I never said cars. Cars are terrible. I would not complained if passenger-only cars were banned everywhere.
> Similar for your suggestion that we should take ships over the ocean, because cruise ships are much more polluting per passenger mile than modern airliners.
There are alternatives like wind power + giant batteries. The fact that weight doesn't matter for ships so much (container ships are more efficient than rail, scaling up is equivalent to shrinking the viscosity of water) opens a lot of doors.
Air travel is generally more energy efficient than trains, beyond a 300-400 mile range, depending on what you're traveling over/through.
Track and right-of-way is a scarce resource with large amounts of embedded energy. The sky, not so much.
Track and right-of-way is a scarce resource with large amounts of embedded energy. The sky, not so much.
That depends on passenger volume. Trains require massive initial investments, but the marginal cost per passenger is very low. Air travel is mostly about marginal costs, and it requires massive infrastructure at endpoints. For example, an aiport serving 50 million passengers/year is two orders of magnitude larger than a railway station with a similar passenger volume. And while the airport would be one of the 30-40 busiest in the world, the railway station would not be particularly noteworthy.
Yea, which is why trains costs are so sensitive to distance- it's massive up front cost is a function of that distance. It's not the stations, it's the rails and right-of-way.
The problem most people ignore is that train marginal-increases max-out at some number of trains per day, before you need an additional set of tracks.
And that happens at a much lower number than most people assume, especially if you're planning on sharing that track with other routes. And even worse if you have to use or cross a freight track.
So not only does efficiency have a min bounds, but also a local-max bounds, where you need a large enough marginal increase to justify the additional rails.
Whereas the airline equivalent is whether to schedule an additional flight. Which is easier to commit to than whether a new track is justified.
The problem most people ignore is that train marginal-increases max-out at some number of trains per day, before you need an additional set of tracks.
And that happens at a much lower number than most people assume, especially if you're planning on sharing that track with other routes. And even worse if you have to use or cross a freight track.
So not only does efficiency have a min bounds, but also a local-max bounds, where you need a large enough marginal increase to justify the additional rails.
Whereas the airline equivalent is whether to schedule an additional flight. Which is easier to commit to than whether a new track is justified.
Train costs are sensitive to sparsely populated regions. As long as there is a sufficiently large city every hour or so, distances don't really matter.
Multi-track railways are common near major cities. They are not that expensive, because adding another set of tracks increases the width of the corridor only marginally.
The airline equivalent of a new set of tracks is building a new runway. Because that's often impossible, landing slots at busy airports have become very valuable. For example, airlines have paid tens of millions for a daily landing slot at Heathrow.
Multi-track railways are common near major cities. They are not that expensive, because adding another set of tracks increases the width of the corridor only marginally.
The airline equivalent of a new set of tracks is building a new runway. Because that's often impossible, landing slots at busy airports have become very valuable. For example, airlines have paid tens of millions for a daily landing slot at Heathrow.
"Multi-track railways are common near major cities. They are not that expensive, because adding another set of tracks increases the width of the corridor only marginally."
About a quarter of all railway passengers in Czechia take the suburban trains around Prague.
We sorely need extra sets of tracks from all directions, because the current tracks are overloaded. Especially the faster trains from other regions do not mix well with the regional trains that stop every 2 km or so.
But it is almost impossible to build those extra sets of tracks in a densely populated major city like Prague. Lots of NIMBYs, the needed land would be very expensive, many buildings would have to be torn down, plus the centre is a protected zone (historical buildings) and the protecting authorities fight tooth and nail against anything that changes the look and feel of the inner city.
As a result, we are stuck with old infrastructure even if new one is sorely needed. There might be a way, namely, to build all the new tracks underground - but that would be very, very expensive.
About a quarter of all railway passengers in Czechia take the suburban trains around Prague.
We sorely need extra sets of tracks from all directions, because the current tracks are overloaded. Especially the faster trains from other regions do not mix well with the regional trains that stop every 2 km or so.
But it is almost impossible to build those extra sets of tracks in a densely populated major city like Prague. Lots of NIMBYs, the needed land would be very expensive, many buildings would have to be torn down, plus the centre is a protected zone (historical buildings) and the protecting authorities fight tooth and nail against anything that changes the look and feel of the inner city.
As a result, we are stuck with old infrastructure even if new one is sorely needed. There might be a way, namely, to build all the new tracks underground - but that would be very, very expensive.
Do it as subways in a way like the new lines in Barcelona did.
edit: By that I mean something like illustrated here https://ca.wikipedia.org/wiki/L%C3%ADnia_9_del_metro_de_Barc...
Make them 15 to 16 meters in diameter to be usable by any train, or use 2 of them side by side. Problem mostly solved.
edit: By that I mean something like illustrated here https://ca.wikipedia.org/wiki/L%C3%ADnia_9_del_metro_de_Barc...
Make them 15 to 16 meters in diameter to be usable by any train, or use 2 of them side by side. Problem mostly solved.
It can be done, but geology under Prague is terrible. A lot of broken layers with lots of sediments and water.
Our subway system was rather expensive to build and maintain, doing this with trains would probably be too expensive even for a fairly rich city like Prague.
There are some rudimentary plans for railway tunnels under the very center of the city, but the expected cost is eye-watering.
Our subway system was rather expensive to build and maintain, doing this with trains would probably be too expensive even for a fairly rich city like Prague.
There are some rudimentary plans for railway tunnels under the very center of the city, but the expected cost is eye-watering.
Tap into the limitless cornucopia of the EU. For protecting the historic scenery, cultural heritage, being good for the environment, enabling shorter travel times, supporting tourism, intercultural exchange...
We're in a phase of low interest rates, resulting in easy money politics. Burn some billions before others do ;->
We're in a phase of low interest rates, resulting in easy money politics. Burn some billions before others do ;->
>"Whereas the airline equivalent is whether to schedule an additional flight. Which is easier to commit to than whether a new track is justified."
Except many world's biggest airports, like Heathrow, are operating at peak capacity and building another runway at heathrow is expensive, controvertial, involves relocating people's homes and is still a political football
Except many world's biggest airports, like Heathrow, are operating at peak capacity and building another runway at heathrow is expensive, controvertial, involves relocating people's homes and is still a political football
Air still has the advantage- runway is not a function of distance to the destination, and runways are not destination specific.
So it's more appropriate to compare it to part of the station cost, along the lines of another boarding area & track, increasing arrivals and departures.
So it's more appropriate to compare it to part of the station cost, along the lines of another boarding area & track, increasing arrivals and departures.
With dedicated track, though, those limits can be quite high.
The Yamanote Line in Tokyo carries around 4 million passengers per day on two tracks.
Yes- and imho, that's the way to do it. Make it competitive in terms of time and trouble and cost and usability. But it's still not going to be more energy efficient than air for most situations & destinations.
The key point, though, is that there should be no easy way for individuals to travel beyond 3-400 miles. It simply is not possible, today or in the foreseeable future, to travel this far without outsized environmental impacts.
But...FREEDOM!
... and fast fashion is probably worse than both if what I read is correct.
FTR: Years go by between everytime I travel by plane so I don't feel I have anything to defend, I just think it is good to keep the big picture in mind.
FTR: Years go by between everytime I travel by plane so I don't feel I have anything to defend, I just think it is good to keep the big picture in mind.
Agree, and the airlines absolutely need to keep working to become more climate friendly just like we need to make road travel better.
But climate-shaming specifically air travel while at the same time driving a non-electric car or using air conditioning without having solar panels is very hypocritical because both of those and many other things are a far bigger part of the total emissions.
But climate-shaming specifically air travel while at the same time driving a non-electric car or using air conditioning without having solar panels is very hypocritical because both of those and many other things are a far bigger part of the total emissions.
People insulting others as hypocritical for critizing something needs to stop.
It's not an insult. What you call criticising, climate shaming someone over one activity while engaging in other more polluting activities, is the exact definition of the word hypocrisy:
> Hypocrisy is the practice of engaging in the same behavior or activity for which one criticizes another
> Hypocrisy is the practice of engaging in the same behavior or activity for which one criticizes another
We coupd sctuallu fly even more efficiently, but slower, with turboprops
There’s a practical maximum amount of thrust to get from a single turboprop engine; to meet performance requirements in the event of the failure of one engine, that puts a practical upper limit on the size of two engine turboprops. Four engine turboprops would likely not be competitive with modern two engine jets, except on the shortest of legs.
Turboprops also fly lower, meaning they’re much more affected by en route weather that turbojets can often climb over. (Low and mid twenties [thousands of feet] is where much of the uncomfortable weather is. Storms that rise into the mid-30s are diverted around by most airplanes.)
Turboprops have their place, but so do jets in air carrier ops.
Turboprops also fly lower, meaning they’re much more affected by en route weather that turbojets can often climb over. (Low and mid twenties [thousands of feet] is where much of the uncomfortable weather is. Storms that rise into the mid-30s are diverted around by most airplanes.)
Turboprops have their place, but so do jets in air carrier ops.
It looks like the future is a bit of a mashup of a turboprop and turbofan. Check out the efficiency of the Pratt and Whitney geared turbofans. On the A220-100 fuel burn (~3,800 pph) is comparable to a CRJ-900 with 35 more seats in a dual class configuration. That’s quite a leap. I’ll see if I can find someone to compare it to a B717 fuel burn, it’s the same number of seats.
On the the other hand commercial air travel is one of the safest means of travel. If you wanted to optimize for safety you would take a scheduled flight to your destination than go by road.
Ah, well. You think so. But would that hold up if traveling by air so much more, for so many shorter trips? What could go wrong?
Unless we dramatically increase vacation time or dramatically increase rail speeds, that would mean that many people would not be able to see their families and friends or travel to events.
Well, in a plane trip you have 3 lost hours before it starts and after it ends, so a normal train, running at 130km/h will be faster than a plane at 850km/h for any trip of less than ~460km.
If you make it a fast train, at 350km/h, it will beat the plane on any trip up to 1700km.
Most trips are short, so no, most trips can be done by train and people still spend less time on them than by plane.
If you make it a fast train, at 350km/h, it will beat the plane on any trip up to 1700km.
Most trips are short, so no, most trips can be done by train and people still spend less time on them than by plane.
I live in Southern California, with family in Kansas, Wisconsin, and New York. The closest one is 2500kms away. The longest is almost 5000kms A train would take a lot longer than a plane.
Even more than just the distance, though, is the fact that there would be no practical way to have direct rail lines to every major city in the US.
Trains are useful, but there is no way they could replace air travel in the US.
Even more than just the distance, though, is the fact that there would be no practical way to have direct rail lines to every major city in the US.
Trains are useful, but there is no way they could replace air travel in the US.
> I live in Southern California, with family in Kansas, Wisconsin, and New York. The closest one is 2500kms away. The longest is almost 5000kms A train would take a lot longer than a plane.
Perhaps people/families have spread themselves all over the continent because in the past energy has been 'too cheap' (i.e., didn't price in externalities).
With carbon pricing people may make different decisions in how far they want to travel from their 'home town', and what that would mean for seeing family.
>95% of the population of the US (and CA) are people who moved across an ocean and had basically zero expectation of seeing their families once they left. The only communication would be letters, telegraphs, and later trans-oceanic telephone calls.
Given the realities of climate change, and what it's cost us with regards to damage to the planet, expectations need to adjust.
Perhaps people/families have spread themselves all over the continent because in the past energy has been 'too cheap' (i.e., didn't price in externalities).
With carbon pricing people may make different decisions in how far they want to travel from their 'home town', and what that would mean for seeing family.
>95% of the population of the US (and CA) are people who moved across an ocean and had basically zero expectation of seeing their families once they left. The only communication would be letters, telegraphs, and later trans-oceanic telephone calls.
Given the realities of climate change, and what it's cost us with regards to damage to the planet, expectations need to adjust.
Travel is extremely economically important, especially for the poor.
Living in a poor, rural county with poor schools and few jobs can really mess things up.
Someone I know is getting divorced.
She was a very high earner who moved to a low-cost of living, low wage area to be with her husbands family.
She had previously earned very high wages, but took a significant pay cut to live with in-laws.
As the divorce is concluding, she realizing that the terms of the divorce prohibit her from taking the kids out of state.
Which means until her kids are 18, she’s effectively trapped in a market where her MS in Engineering gets her a job at Walmart.
She had previously worked for a major firm in New York, and then worked for a the local government until she had to resign.
So she’s basically screwed.
Plenty of people have skills and credentials that can only be used with relocation. A MA in Journalism isn’t very helpful outside big cities.
Living in a poor, rural county with poor schools and few jobs can really mess things up.
Someone I know is getting divorced.
She was a very high earner who moved to a low-cost of living, low wage area to be with her husbands family.
She had previously earned very high wages, but took a significant pay cut to live with in-laws.
As the divorce is concluding, she realizing that the terms of the divorce prohibit her from taking the kids out of state.
Which means until her kids are 18, she’s effectively trapped in a market where her MS in Engineering gets her a job at Walmart.
She had previously worked for a major firm in New York, and then worked for a the local government until she had to resign.
So she’s basically screwed.
Plenty of people have skills and credentials that can only be used with relocation. A MA in Journalism isn’t very helpful outside big cities.
> Travel is extremely economically important, especially for the poor.
"Travel" or "movement"?
I am the first generation to be born in the country I live in. When my (grand)parents left, they left under the assumption that there would be no, or maybe very little, chance of going back to the Old Country. They took a boat over the course of many weeks to traverse an ocean; an era before cheap air travel.
When people move in the future, to hopefully have a better life than where they current are, it may be that they may not be able to go back (as easily) to where they came from.
The fact that we can now travel back and forth cheaply over great distances could simply be a temporary blip in human history, and we should perhaps consider this era could be ending. You can still move, but it will be more 'permanent' going forward, and travel is will be less frequent/easy/cheap/etc.
"Travel" or "movement"?
I am the first generation to be born in the country I live in. When my (grand)parents left, they left under the assumption that there would be no, or maybe very little, chance of going back to the Old Country. They took a boat over the course of many weeks to traverse an ocean; an era before cheap air travel.
When people move in the future, to hopefully have a better life than where they current are, it may be that they may not be able to go back (as easily) to where they came from.
The fact that we can now travel back and forth cheaply over great distances could simply be a temporary blip in human history, and we should perhaps consider this era could be ending. You can still move, but it will be more 'permanent' going forward, and travel is will be less frequent/easy/cheap/etc.
Unless you can move your entire family, then movement implies travel at least twice a year in the US.
> […] then movement implies travel at least twice a year in the US.
Under the current regime of 'cheap' travel in which the externalities of climate change are probably not taken into account.
Under the current regime of 'cheap' travel in which the externalities of climate change are probably not taken into account.
Why? Building a community, grass roots style, on the net...fight the right. Righten the flight. Show where to go with flow. Make it glow...
Yes, you are not on that "most" category. (But that 2500km is close to it, so trains may still be more comfortable.)
to be fair, even for short trips trains require a minimum passenger flux before it's more efficient than planes. So even strictly talking about carbon emissions, trains are a net loss for most trajectories, but a large gain for most passengers.
to be fair, even for short trips trains require a minimum passenger flux before it's more efficient than planes. So even strictly talking about carbon emissions, trains are a net loss for most trajectories, but a large gain for most passengers.
Well, if there was no air travel, rail lines everywhere would likely be practical... again.
If trains could go 250km/h on average, that 5000km trip would take 20 hours - that's plausible for an overnight trip, leave 6pm, arrive 10am. A flight over this is distance is probably a much more stressful red eye.
Sure this is quite speculative, but perhaps less so than hyperloop dreams, or supersonic aircraft that somehow have no environmental impact.
If trains could go 250km/h on average, that 5000km trip would take 20 hours - that's plausible for an overnight trip, leave 6pm, arrive 10am. A flight over this is distance is probably a much more stressful red eye.
Sure this is quite speculative, but perhaps less so than hyperloop dreams, or supersonic aircraft that somehow have no environmental impact.
That seems a strange argument… yes, if we didn’t have planes, trains would be our best option… but it would be a much worse experience. 20 hours is a lot longer than the 5 it takes me to fly to New York.
If there was no air travel, I would just travel a lot less. If you want to argue that the environmental cost of air travel is too great to allow it to happen is one thing, but done act like it wouldn’t make the travel experience a lot worse.
If there was no air travel, I would just travel a lot less. If you want to argue that the environmental cost of air travel is too great to allow it to happen is one thing, but done act like it wouldn’t make the travel experience a lot worse.
I'd like to see a graph of miles flown per year by decile.
internet foo
Found this. As I suspected, hockey stick graph.
https://news.gallup.com/poll/1579/airlines.aspx
Half the people in the US don't fly at all. 25% fly 1-2 times a year. People that don't fly at all, and people that fly 1-2 times year. Probably wouldn't be much impacted if they had to take a high speed train instead of a plane.
internet foo
Found this. As I suspected, hockey stick graph.
https://news.gallup.com/poll/1579/airlines.aspx
Half the people in the US don't fly at all. 25% fly 1-2 times a year. People that don't fly at all, and people that fly 1-2 times year. Probably wouldn't be much impacted if they had to take a high speed train instead of a plane.
It’s not a strange argument. Read the discussion again, which starts with the thesis
> All overland passenger transport should be rail.
Then it was claimed that this is impossible. My argument is saying it’s possible to have rail replace rail, for example if air travel was severely restricted.
> All overland passenger transport should be rail.
Then it was claimed that this is impossible. My argument is saying it’s possible to have rail replace rail, for example if air travel was severely restricted.
6 PM to 10 AM is only 16 hours. Even with 3 time zones, you’d only be at 19 hours. 250kph straight line equivalent is unlikely given the terrain in the way (Rocky Mountains, primarily).
Tonnels, we are made massive ones through the alps in europe
https://en.m.wikipedia.org/wiki/Gotthard_Base_Tunnel
https://en.m.wikipedia.org/wiki/Gotthard_Base_Tunnel
Gotthard is impressive, but it took the Swiss 17 years to build it. Nearby, Brenner Base Tunnel is under construction between Italy and Austria, and it is expected to take 25 years to complete.
I can't imagine how long would it take to tunnel through the Rockies. Look at the map, they are far wider than the Alps. Getting through the Rockies is like getting from Denmark to Croatia.
I can't imagine how long would it take to tunnel through the Rockies. Look at the map, they are far wider than the Alps. Getting through the Rockies is like getting from Denmark to Croatia.
Use the Army Corps of Engineers, Navy Sea Bees, something like that. Look at https://en.wikipedia.org/wiki/Seikan_Tunnel going between islands under the Japan Seas in an earthquake area.
Think BIGGRRRR! (Aggressively so, instead of sissying around!)
edit: also not to forget about 'Nuclear Tunnel Boring Machines/Subterrene' https://havacuppahemlock1.blogspot.com/2015/06/nuclear-power...
cf. "Trans-Planetary Subway Systems
A Burgeoning Capability
by Robert M. Salter
February 1978"
https://www.rand.org/pubs/papers/P6092.html
Think BIGGRRRR! (Aggressively so, instead of sissying around!)
edit: also not to forget about 'Nuclear Tunnel Boring Machines/Subterrene' https://havacuppahemlock1.blogspot.com/2015/06/nuclear-power...
cf. "Trans-Planetary Subway Systems
A Burgeoning Capability
by Robert M. Salter
February 1978"
https://www.rand.org/pubs/papers/P6092.html
Better get started soon then! Once you make a tonnel, it stays there forever, it's a good investment
Indeed, if we want tunnels to make a rail network cross the Rockies, we had really better get started, since you'd need 5 east-west routes to make trains practical ("less impractical"?) to cross the Rockies. No one is going to take an additional 1000 mile (7+ hour) diversion north-south to pass through a tunnel to repeat that north-south diversion on the other side.
China built tens of thousands of km of high speed rail for 350km/h. Largely using prefab elevated tracks, with occasional tunnels.
Again it’s difficult, but possible if a replacement for air travel was considered a necessity.
Again it’s difficult, but possible if a replacement for air travel was considered a necessity.
/me hypes the loop...
I don’t lose 6 hours on a typical airline trip. Domestic, I tend to arrive around an hour before gate close time. International from the US, about 90 minutes. For a train, I’d still plan on a 30 minute safety buffer (to protect against en route delays to the station). Add another 30 minutes over the train for boarding, push, and taxi. So, I’m probably giving up an hour plus/minus however closer the train station is vs the airport.
Arriving, baggage claim rarely takes more than 30 minutes. (Delta “guarantees” 20 minutes on domestic flights.) With no checked bags, it’s the 10 minute walk through the airport and then plus/minus ground transport differences vs the train.
I can’t imagine that most people are spotting the train a 6 hour head-start, unless the live upstairs from the train station and are extremely nervous about missing their flight.
Arriving, baggage claim rarely takes more than 30 minutes. (Delta “guarantees” 20 minutes on domestic flights.) With no checked bags, it’s the 10 minute walk through the airport and then plus/minus ground transport differences vs the train.
I can’t imagine that most people are spotting the train a 6 hour head-start, unless the live upstairs from the train station and are extremely nervous about missing their flight.
Of course it depends, but train stations tend to be in the center of a city, so you start from the center of A and arrive to the center of B.
With planes, airports are way off the city centre, I think that there are few airports (here in Europe) serving large cities that can be reached in less than 1 hour from the city centre, and that applies to both A and B, to this you add, unless you use a private means of transportation (car-taxi), a half an hour for the timetable of the bus or train you need to take to/from the airport, as it won't necessarily be synchronized with your flight departure/arrival.
With planes, airports are way off the city centre, I think that there are few airports (here in Europe) serving large cities that can be reached in less than 1 hour from the city centre, and that applies to both A and B, to this you add, unless you use a private means of transportation (car-taxi), a half an hour for the timetable of the bus or train you need to take to/from the airport, as it won't necessarily be synchronized with your flight departure/arrival.
That kinda implies you leave and go to the city centre each time, which might not be the case. Living next to a major train station is usually very expensive. If you're visiting family in the suburbs, you might be closer to the airport than the city centre (or be "unlucky" and have the airport on the other side of the city).
It sounds pretty situational to me.
Uhm, arriving about 9:00AM at Hamburg Airport
[1] https://openstreetmap.de/karte.html?zoom=11&lat=53.61524&lon...
visiting
[2] https://en.wikipedia.org/wiki/Hamburg_Messe_und_Congress
you'd take
[3] https://geofox.hvv.de/jsf/home.seam?execute=true&date=05.07....
I see no problem here.
(edit: WHAT?)
[1] https://openstreetmap.de/karte.html?zoom=11&lat=53.61524&lon...
visiting
[2] https://en.wikipedia.org/wiki/Hamburg_Messe_und_Congress
you'd take
[3] https://geofox.hvv.de/jsf/home.seam?execute=true&date=05.07....
I see no problem here.
(edit: WHAT?)
The numbers on my comment are for 3 hours, not 6. (Yeah, the text is not very clear on that.)
Yes, and for longer trips, besides the high speed trains, there are (were) also night trains, but for some reasons most of them were canceled (and/or the prices became less and less competitive), an old thread about this:
https://news.ycombinator.com/item?id=19557848
Maybe they will start to organize a few more of these trains, the level of stress was so much lower on (overnight) trains when compared to planes when moving in Europe.
https://news.ycombinator.com/item?id=19557848
Maybe they will start to organize a few more of these trains, the level of stress was so much lower on (overnight) trains when compared to planes when moving in Europe.
That trend of canceling them seems to be in reversal, at least a bit. https://www.nightjet.com/en/reiseziele
If we had high-speed rail everywhere at 300km/h you can cross almost any country overnight, that radius of 3600km would give you 80% of all plane travel.
At energy and cost levels that exceed airline travel, per passenger-mile.
Do you have a citation for that?
Quick Googling doesn't reveal any obvious authoritative answers (but a ton of guessing and unsubstantiated claims). The most authoritative/unbiased source seems to be this Wikipedia article:
https://en.wikipedia.org/wiki/Energy_efficiency_in_transport
But the head-to-head comparisons are mostly gaps when it comes to trains, and the sections on trains and planes are in completely different families of units that makes comparison extremely non-trivial. :(
Quick Googling doesn't reveal any obvious authoritative answers (but a ton of guessing and unsubstantiated claims). The most authoritative/unbiased source seems to be this Wikipedia article:
https://en.wikipedia.org/wiki/Energy_efficiency_in_transport
But the head-to-head comparisons are mostly gaps when it comes to trains, and the sections on trains and planes are in completely different families of units that makes comparison extremely non-trivial. :(
It was covered in a sustainable engineering class I took.
There's not much generic into about it because every rail route proposal is different, even between the same destinations. Depends a lot on geography and what's already there.
You basically need to do a full Life Cycle Analysis (LCA) for each route.
Sometimes they're included in the EIS for a proposed project. That's prob the best place to start.
But there's a reason most of the rail routes that keep getting proposed in the US are regional. Track and right-of-way is expensive, in both dollars and energy. Even moreso with high speed, where you need grade-seperated crossings and long, wide turns.
Most people think track is shareable or reusable, but the real world limits to track capacity (trains per day) makes economies of scale difficult to implement.
I posted it elsewhere, but the practical limit for non-high-speed rail is 300-400 miles, before airplanes start to make more sense.
High speed is difficult to even estimate, since we don't have much here to base it on.
There's not much generic into about it because every rail route proposal is different, even between the same destinations. Depends a lot on geography and what's already there.
You basically need to do a full Life Cycle Analysis (LCA) for each route.
Sometimes they're included in the EIS for a proposed project. That's prob the best place to start.
But there's a reason most of the rail routes that keep getting proposed in the US are regional. Track and right-of-way is expensive, in both dollars and energy. Even moreso with high speed, where you need grade-seperated crossings and long, wide turns.
Most people think track is shareable or reusable, but the real world limits to track capacity (trains per day) makes economies of scale difficult to implement.
I posted it elsewhere, but the practical limit for non-high-speed rail is 300-400 miles, before airplanes start to make more sense.
High speed is difficult to even estimate, since we don't have much here to base it on.
China has more high-speed than the rest of the world combined, with even remote parts of China hooked up to the rail network.
And when you compare energy, you have to take into account that Rail is already electric, powered directly by grid without batteries or any other efficiency loss in between.
Airplanes use fuel that takes a lot of energy to refine and deliver, and will at best use hydrogen in 15 years which is 40% efficient to produce, plus losses in compression, delivery, engine, etc.
And when you compare energy, you have to take into account that Rail is already electric, powered directly by grid without batteries or any other efficiency loss in between.
Airplanes use fuel that takes a lot of energy to refine and deliver, and will at best use hydrogen in 15 years which is 40% efficient to produce, plus losses in compression, delivery, engine, etc.
I'm not against it. But it's usually not more energy efficient. Life Cycle Analysis takes all the inefficiencies you mention into account, down to the zip code, and includes thing like present and future mix of electrical generation.
Doing it because China is, isn't really a reason.
You can take into account electrifying rail, but it doesn't really change much. This all gets taken into account.
>other efficiency loss in between.
The grid has plenty of inefficiencies, especially if we have to start designing beyond capacity to account for intermittent sources. But electricity's main inefficiency is in its creation.
LCAs take all of this into account. It's the whole purpose of doing one. Embedded energy involved in manufacture, refining, transport, everything, is all added up based on things like location and present and/or future inputs.
Doing it because China is, isn't really a reason.
You can take into account electrifying rail, but it doesn't really change much. This all gets taken into account.
>other efficiency loss in between.
The grid has plenty of inefficiencies, especially if we have to start designing beyond capacity to account for intermittent sources. But electricity's main inefficiency is in its creation.
LCAs take all of this into account. It's the whole purpose of doing one. Embedded energy involved in manufacture, refining, transport, everything, is all added up based on things like location and present and/or future inputs.
One of the reasons why China built such a network so fast is the top-down structure of the state. If the authorities decide to build something just across your neighbourhood, you are in no position to challenge them.
Although I like trains, I wouldn't want to live in such society.
Although I like trains, I wouldn't want to live in such society.
Thanks. Is there at least some kind of super-elementary comparison?
E.g. energy consumption per-passenger-mile for a fully occupied Japanese bullet train while moving at maximum speed, versus for a fully occupied Boeing 737 at cruising altitude?
Obviously there are a million other factors, like takeoffs and landings, and trains stopping, as well as fuel vs electric, but wondering about even just the most basic operation.
E.g. energy consumption per-passenger-mile for a fully occupied Japanese bullet train while moving at maximum speed, versus for a fully occupied Boeing 737 at cruising altitude?
Obviously there are a million other factors, like takeoffs and landings, and trains stopping, as well as fuel vs electric, but wondering about even just the most basic operation.
Thank you, and great username for the clarification :).
It would mean many people wouldn't choose to live flying distance from their families in the first place and they would go to local events, and people would connect more with local community.
The trouble is that we've all organized our lives around fast air travel and it's hard to unring that bell. I might not interviewed at a tech company in SF and then moved out from Pennsylvania if I knew that every journey back to see my parents would take 5 days each way by train. Many of us have close relationships scattered across long distances, which was less true before the advent of affordable air travel.
Yes, and that is not a great prospect.
however, it's going to happen regardless, since this way of living is not sustainable. The only choice that is ours is whether we prefer to anticipate this change and build a decent alternative, or whether we prefer to have it inflicted on us.
however, it's going to happen regardless, since this way of living is not sustainable. The only choice that is ours is whether we prefer to anticipate this change and build a decent alternative, or whether we prefer to have it inflicted on us.
Absolutely not. 300 kph HSR rail exists in developed countries.
(2680 miles) / (300 kilometers per hour) = 14.3768064 hours
That's coast to coast in ~ 1/2 day.
Ships and blimps represent a much larger decrease in travel time over airplanes than rail. They perhaps pose a to be solved, but rail doesn't.
(2680 miles) / (300 kilometers per hour) = 14.3768064 hours
That's coast to coast in ~ 1/2 day.
Ships and blimps represent a much larger decrease in travel time over airplanes than rail. They perhaps pose a to be solved, but rail doesn't.
You do need favorable terrain for that speed. Much of western US is not exactly flat, so the costs to build this will definitely not be cheap. More likely something slower and a multi-day trip.
I’d still consider a say 48h trip from SoCal to NYC provided I could work over wifi, but otherwise it’s really a nonstarter.
I’d still consider a say 48h trip from SoCal to NYC provided I could work over wifi, but otherwise it’s really a nonstarter.
And you can go ecen faster
>"TGV called V150 holds the record for the highest speed on any national rail system - it hit a whopping 357.2 mph "
>"TGV called V150 holds the record for the highest speed on any national rail system - it hit a whopping 357.2 mph "
Probably not during normal operations. IIRC they put more mechanical tension on the overhead catenary, also more voltage on it, and used slightly larger wheels. That was more of testing the absolute limits of what you can do with that sort of system, materials- and mechanics-wise.
Don’t look at a geographic district map, look at a topographical map. Or does the solution include a tunnel connecting Eastern Colorado with San Francisco?
Yeah, but that is only from one part of the coast to one part. You would have to have so many lines to connect all the cities.
Yes, but even if we double the time estimate, I don't think that's prohibitively slow.
Only with the many day duration to traverse oceans eihtou planes do I get worried.
Only with the many day duration to traverse oceans eihtou planes do I get worried.
Most travel is business. Business events mostly don't require travel as we saw this year.
And without business travellers many or even most flights wouldn't be financially viable.
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One could imagine submerged floating rail tunnels for going over the oceans by rail. Say about 30 to 50 meters deep to be isolated from the weather, not disturbing the remaining shipping. Also usable as sensor platform, carrier for fiber optics. And enabler for floating cities, resorts, aqua-, wind-, and wave-farms out there.
Wait until you hear about SpaceX.
A Falcon 9 launch produces comparable carbon emissions to a trans-Atlantic 777 flight. There are considerably more trans-Atlantic 777 flights than there are Falcon 9 launches.
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Do you mean the methane-powered Starship, for which they plan to use the Sabatier process to get CH4 from the atmosphere?
Is the process expensive compared to just buying CH4 otherwise?
When Tesla announced superchargers, they were all about solar panels and cars powered by sunlight, but for the serious rollout they had to go with the more easily scalable, cheaper option, so very few superchargers have solar panels after all.
When Tesla announced superchargers, they were all about solar panels and cars powered by sunlight, but for the serious rollout they had to go with the more easily scalable, cheaper option, so very few superchargers have solar panels after all.
If you think that we use too much fuel, increase the price of fuel. Don't just randomly oppose specific technologies that use fuel on the grounds that you, personally, yellow_led, don't feel those technologies are necessary.
So it's alright to increase the price of fuel because yellow_led, personally, thinks too much fuel is being used, but not alright to randomly oppose specific technologies on the grounds that yellow_led, personally, thinks they use too much fuel?
I'm not following your logic. Also I don't know how you randomly oppose specific things.
I'm not following your logic. Also I don't know how you randomly oppose specific things.
>yellow_led, personally, thinks too much fuel is being used
>randomly oppose specific technologies on the grounds that yellow_led, personally, thinks they use too much fuel
I think the assumption is that we mostly agree on the first item, but the second one is supposed to be a means to the first. Which yellow_led and others think is a big mistake.
>I don't know how you randomly oppose specific things.
Random means arbitrary here, I think. Without sound logical reasoning.
>randomly oppose specific technologies on the grounds that yellow_led, personally, thinks they use too much fuel
I think the assumption is that we mostly agree on the first item, but the second one is supposed to be a means to the first. Which yellow_led and others think is a big mistake.
>I don't know how you randomly oppose specific things.
Random means arbitrary here, I think. Without sound logical reasoning.
Richwine, of nasa, told me that he thinks S.S.T. could cut some flight times in half. But, he said, supersonic flight wouldn’t proportionately reduce over-all travel time until we fixed our infrastructure: How much better is flying from L.A.X. to J.F.K. in two or three hours if you spend twice that time in airports and traffic?
OT but I think better than another boring air travel bad spiel -
Dyson did some cool computer modelling around Helmholtz acoustic cavities to create quieter fans. I think there's a lot of interesting stuff we can re-visit today because of improved computer power around noise pollution -
“At Dyson we make hundreds of incremental changes rather than one leap forward at a time,” said Schneider. “That means we produce and test hundreds of prototypes for each project. 640 prototypes from handmade models to 3D printed designs were made during the development of the Cool fan.”
https://www.theguardian.com/technology/2014/mar/06/dyson-sil...
Dyson did some cool computer modelling around Helmholtz acoustic cavities to create quieter fans. I think there's a lot of interesting stuff we can re-visit today because of improved computer power around noise pollution -
“At Dyson we make hundreds of incremental changes rather than one leap forward at a time,” said Schneider. “That means we produce and test hundreds of prototypes for each project. 640 prototypes from handmade models to 3D printed designs were made during the development of the Cool fan.”
https://www.theguardian.com/technology/2014/mar/06/dyson-sil...
Solving some societal or civilisational challenge with supersonic flight seems very narrow minded now.
Yes I would like to fly to my work HQ faster but due to pandemic I have not visited in 3 years now and it’s been fine, so a better solution is excellent remote work tools such as HQ videoconferencing etc which is such an easier problem, yet many people and companies still struggle with it.
In the overall ROI for things to do, I bet we shouldn’t be building businesses that REQUIRE supersonic flight to succeed.
Fast transportation, like fast computers, or fast appliances, aren't required. They just make life better.
It would be nice if we had publically funded communication etc tools. I am not seeing a valid business nodel here that does not involve either massive spying, or poor people loosing access to rest of society.
How does having public funding for communication help? Having a zoom equipped laptop available for use in a county building isn’t much of a stretch. Public funding of communication will also guarantee spying.
Spying is already guaranteed. Public funding means accountability in well-functioning democracies (sadly rare).
I hope not mainly because where I live in south-eastern Canada we seem to be the tailpipe of North America. All aircraft heading east seem to go over my region.
The summer in non-pandemic times) is a constant parade of large passenger jets flying over. The jets are high up and in the evening you hear the rumble as the aircraft highlighted by the sun fly over while the ground is in evening shadows.
Even a dozen US military Osprey aircraft fly over a few weeks ago.
I wouldn't want a dozen large supersonic passenger aircraft going over all the time.
The summer in non-pandemic times) is a constant parade of large passenger jets flying over. The jets are high up and in the evening you hear the rumble as the aircraft highlighted by the sun fly over while the ground is in evening shadows.
Even a dozen US military Osprey aircraft fly over a few weeks ago.
I wouldn't want a dozen large supersonic passenger aircraft going over all the time.
Do you live in Nova Scotia or New Brunswick? That seems to be where flights from NE USA to Europe fly over generally.
That said they should be at cruising altitude by there. If you can hear them at 36k feet, it must be fairly quiet where you live!
I live close to the path of the Heathrow approach, and planes tend to fly over me at about 5k feet, and I have to say that it's pretty rare I even hear them.
That said they should be at cruising altitude by there. If you can hear them at 36k feet, it must be fairly quiet where you live!
I live close to the path of the Heathrow approach, and planes tend to fly over me at about 5k feet, and I have to say that it's pretty rare I even hear them.
You're close, I'm in Prince Edward Island. Yes it's pretty quiet here even in the largest town.
Often I can hear the jets at night from inside my house. That's if there isn't any wind.
Often I can hear the jets at night from inside my house. That's if there isn't any wind.
Fortunately there are no night flights to and from the airport here. Nonetheless, depending on weather I can hear them, mostly from/to Paris, France from/to many destinations in Asia, mostly China. They all cross over here, apparently.
[A] passenger version of the X-59 would be two hundred and thirty feet long, about the length of a Boeing 777, and carry around fifty people.
That’s 22ft longer than Concorde with half the px.
https://www.britishairways.com/en-gb/information/about-ba/hi...
That’s 22ft longer than Concorde with half the px.
https://www.britishairways.com/en-gb/information/about-ba/hi...
Setting everything else aside, flying from LAX to Heathrow in 2-3 hours does sound pretty amazing. Even if it was say 2 or 3 times the price, I'd seriously consider it.
I remember the first time I paid for the HSR option from Amsterdam to Brussels, way easier
I remember the first time I paid for the HSR option from Amsterdam to Brussels, way easier
In a rapidly warming world, I don't see the need to spend all that energy on supersonic transport when Zoom will do just fine. There are sustainable fuels, but they use a ton of energy. It's an extravagance the world cannot afford.
People definitely shouldn't fly if they don't need to, but I think you're overestimating the warming effect from aviation. Estimates put it in the ~3% range overall [1]. Most of that (80%) was passenger travel [2] (pre-pandemic) and 20% cargo.
The EU's push for short-haul flight bans [3] makes a lot of sense though, especially when high-speed (and sometimes electrified) rail is an option.
[1] https://ourworldindata.org/co2-emissions-from-aviation
[2] https://ourworldindata.org/co2-emissions-from-transport
[3] https://en.wikipedia.org/wiki/Short-haul_flight_ban
The EU's push for short-haul flight bans [3] makes a lot of sense though, especially when high-speed (and sometimes electrified) rail is an option.
[1] https://ourworldindata.org/co2-emissions-from-aviation
[2] https://ourworldindata.org/co2-emissions-from-transport
[3] https://en.wikipedia.org/wiki/Short-haul_flight_ban
What's the "right" temperature for the world?
We'll be fine.
We'll be fine.
Sound is one thing, but there are other more significant obstacles.
The benefits of faster travel really show on longer distances (London to Sydney for example). But over land, there just aren’t many common routes where the several hour savings would be worth it.
The big challenges relate to risk. What happens to the vehicle when a major failure happens at high speed? What about sudden pressure loss at high altitude? Or mechanical failure or weather which causes a diversion (how much ground do you cover just turning around?).
I find it hard to see legitimate overall benefits.
Frankly, I think we could make greater overall time benefits by optimizing airport and boarding improvements.
The benefits of faster travel really show on longer distances (London to Sydney for example). But over land, there just aren’t many common routes where the several hour savings would be worth it.
The big challenges relate to risk. What happens to the vehicle when a major failure happens at high speed? What about sudden pressure loss at high altitude? Or mechanical failure or weather which causes a diversion (how much ground do you cover just turning around?).
I find it hard to see legitimate overall benefits.
Frankly, I think we could make greater overall time benefits by optimizing airport and boarding improvements.
> What happens to the vehicle when a major failure happens at high speed? What about sudden pressure loss at high altitude? Or mechanical failure…
The same thing that happens in any other plane.
> … or weather which causes a diversion (how much ground do you cover just turning around?).
This is an extremely weird concern. There’s so much wrong with it I’m not even sure where to start: planes can slow down, sharp turns due to weather mid-route are not even really a thing, I’m not even sure why covering extra ground is such a bad thing anyway.
The same thing that happens in any other plane.
> … or weather which causes a diversion (how much ground do you cover just turning around?).
This is an extremely weird concern. There’s so much wrong with it I’m not even sure where to start: planes can slow down, sharp turns due to weather mid-route are not even really a thing, I’m not even sure why covering extra ground is such a bad thing anyway.
> The same thing that happens in any other plane.
https://en.wikipedia.org/wiki/List_of_aircraft_structural_fa...
The faster you are traveling (which really matters as a factor of the drag you are experiencing), the more serious any event is which changes the shape of your vehicle. Even non structural failures, such as an engine cowling coming off mid-flight can strike other parts of the aircraft, resulting in damage and changes to the structure.
Tolerances for these events are much lower the faster you're going, meaning the outcome is more likely to be severe if you're traveling much faster than we currently do with passenger aircraft.
Military fighters are built with higher tolerances and structural strength (and come in heavier, requiring more fuel and reducing range). Commercial aircraft are just impractical to operate safely at such high speeds.
With respect to diversions and changes of route, you have to consider several things.
Faster, heavier aircraft need longer runways to land. That limits your alternate landing choices. Diversions may cost you more fuel since they may be much greater distances away.
And you cannot simply make a "sharp turn" at high speed. Your passengers (and the airframe on a large craft) are not prepared for 4G turns. They aren't even designed for 2G turns.
Ask yourself this, can you turn your car as sharply at highway speed as you can in the parking lot? Sure you can slow down and then turn, but that takes time. That would not be considered "sharp". So while you're decelerating and turning, you are eating up great distances. It would be easy to overshoot a nearby location; thus you would need to plan ahead, take big slow turns, etc. Do you have enough extra fuel for that? Are you able/allowed to pass through all airspaces conveniently, or will that require extra planning and maneuvering?
The complexity of flying larger and/or faster aircraft is much more than one might think.
https://en.wikipedia.org/wiki/List_of_aircraft_structural_fa...
The faster you are traveling (which really matters as a factor of the drag you are experiencing), the more serious any event is which changes the shape of your vehicle. Even non structural failures, such as an engine cowling coming off mid-flight can strike other parts of the aircraft, resulting in damage and changes to the structure.
Tolerances for these events are much lower the faster you're going, meaning the outcome is more likely to be severe if you're traveling much faster than we currently do with passenger aircraft.
Military fighters are built with higher tolerances and structural strength (and come in heavier, requiring more fuel and reducing range). Commercial aircraft are just impractical to operate safely at such high speeds.
With respect to diversions and changes of route, you have to consider several things.
Faster, heavier aircraft need longer runways to land. That limits your alternate landing choices. Diversions may cost you more fuel since they may be much greater distances away.
And you cannot simply make a "sharp turn" at high speed. Your passengers (and the airframe on a large craft) are not prepared for 4G turns. They aren't even designed for 2G turns.
Ask yourself this, can you turn your car as sharply at highway speed as you can in the parking lot? Sure you can slow down and then turn, but that takes time. That would not be considered "sharp". So while you're decelerating and turning, you are eating up great distances. It would be easy to overshoot a nearby location; thus you would need to plan ahead, take big slow turns, etc. Do you have enough extra fuel for that? Are you able/allowed to pass through all airspaces conveniently, or will that require extra planning and maneuvering?
The complexity of flying larger and/or faster aircraft is much more than one might think.
They go higher than normal passenger jets. Thus they could glide longer, because they'd start from an altitude of anywhere between 13 to 16 kilometers up, maybe even 20km. There is almost no weather to speak of there, and if so it wouldn't require a sharp turn, because anything reaching up there would be visible from far away. (like a thunderstorm)
That's the whole point of so called high-altitude/high-atmospheric platforms as an alternative to low orbiting satellites. (Think stationary blimp with many antennae/transponder on its belly for internet, or something)
What are you smoking!?
That's the whole point of so called high-altitude/high-atmospheric platforms as an alternative to low orbiting satellites. (Think stationary blimp with many antennae/transponder on its belly for internet, or something)
What are you smoking!?
> The faster you are traveling (which really matters as a factor of the drag you are experiencing), the more serious any event is which changes the shape of your vehicle. Even non structural failures, such as an engine cowling coming off mid-flight can strike other parts of the aircraft, resulting in damage and changes to the structure.
Yes, an engine falling off will be more impactful to a plane traveling at supersonic speeds. But these types of incidents are an extremely minor fraction of overall failures, and particularly during cruise at altitude (e.g., when the risk of bird strikes is minimal).
Engineering steps can be taken to minimize risks like this further since the consequences of failure are higher.
> Commercial aircraft are just impractical to operate safely at such high speeds.
This argument was made when the first jetliners were being rolled out too. It carries about as much weight now as it did then.
> Faster, heavier aircraft need longer runways to land. That limits your alternate landing choices. Diversions may cost you more fuel since they may be much greater distances away.
This hasn't stopped faster, heavier aircraft from becoming commercial successes so far.
A diversion is already extremely expensive for a myriad of reasons. Schedules, aircrew, and sometimes planes have to be shuffled around. Stranded passengers often need accommodation and/or alternative transport arranged. Airfare credits are often handed out. Incurring slightly higher fuel costs from having to divert a bit farther is just not that significant of a factor here, and one that is easily compensated for by adjusting ticket prices.
Bumping the cost of an uncommon, already-expensive event by a few percentage points just doesn't move the needle much.
> And you cannot simply make a "sharp turn" at high speed. Your passengers (and the airframe on a large craft) are not prepared for 4G turns. They aren't even designed for 2G turns.
That's my point. Nobody is making sharp turns in airliners anyway. Routes are determined with weather accounted for in advance, and if a diversion around unplanned weather mid-flight is needed, airliners make long, sweeping turns to avoid it already.
Yes, an engine falling off will be more impactful to a plane traveling at supersonic speeds. But these types of incidents are an extremely minor fraction of overall failures, and particularly during cruise at altitude (e.g., when the risk of bird strikes is minimal).
Engineering steps can be taken to minimize risks like this further since the consequences of failure are higher.
> Commercial aircraft are just impractical to operate safely at such high speeds.
This argument was made when the first jetliners were being rolled out too. It carries about as much weight now as it did then.
> Faster, heavier aircraft need longer runways to land. That limits your alternate landing choices. Diversions may cost you more fuel since they may be much greater distances away.
This hasn't stopped faster, heavier aircraft from becoming commercial successes so far.
A diversion is already extremely expensive for a myriad of reasons. Schedules, aircrew, and sometimes planes have to be shuffled around. Stranded passengers often need accommodation and/or alternative transport arranged. Airfare credits are often handed out. Incurring slightly higher fuel costs from having to divert a bit farther is just not that significant of a factor here, and one that is easily compensated for by adjusting ticket prices.
Bumping the cost of an uncommon, already-expensive event by a few percentage points just doesn't move the needle much.
> And you cannot simply make a "sharp turn" at high speed. Your passengers (and the airframe on a large craft) are not prepared for 4G turns. They aren't even designed for 2G turns.
That's my point. Nobody is making sharp turns in airliners anyway. Routes are determined with weather accounted for in advance, and if a diversion around unplanned weather mid-flight is needed, airliners make long, sweeping turns to avoid it already.
Also, you might want to actually read the Wikipedia article you linked.
There have been ten total cases of structural failure in the past twenty years of aviation. Two of those involved spacecraft (Space Shuttle Columbia and VSS Enterprise). One of them was a terrorist bombing (Metrojet 9268). One was a fighter jet (F-15).
So six left. In all of those six, there were essentially 100% casualties. So how exactly would a supersonic jet be "worse"?
There have been ten total cases of structural failure in the past twenty years of aviation. Two of those involved spacecraft (Space Shuttle Columbia and VSS Enterprise). One of them was a terrorist bombing (Metrojet 9268). One was a fighter jet (F-15).
So six left. In all of those six, there were essentially 100% casualties. So how exactly would a supersonic jet be "worse"?
Is it possible to emit a small plasma field to eliminate air in front of the vehicle? How much power is needed?
Starship will be doing this within a month or two max. Florida to Hawaii in thirty minutes.
Yes, but probably only over countries we are actively bombing.
The better question, given Covid and the climate crisis, is 'Will we ever fly again? Is the age of affordable air travel over?'
Prices are elevated at the moment but people are already back to flying in large numbers at least in the US.
Thinking more about the quarantine and testing costs flying internationally at the moment. And a post-Covid world with bankrupt airlines and a lot less flight availability. With the end of the Covid crisis blending into a more serious fight against climate change.
International travel seems like more trouble than it's worth at the moment barring urgent need. One organization I know moved an early fall event from a non-US location to the US. Presumably, all going well, they're likely to at least get US audience/speakers.
Not clear to me how big an effect climate change will have unless fuel taxes are really ramped up--which is of course possible.
Not clear to me how big an effect climate change will have unless fuel taxes are really ramped up--which is of course possible.
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