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"I don't think that word means what you think it means." > helping our nation’s airports support more travelers, grow their local economies and prepare for the

"I don't think that word means what you think it means." > helping our nation’s airports support more travelers, grow their local economies and prepare for the future of low-carbon aviation. I doubt a vision of growth is compatible with "sustainability". In fact, I find it highly unlikely.

XorNot 4y ago
You can synthesize jet fuel from CO2 and renewable energy. Or biologically derived products. These are all use cases where consumption won't outstrip capacity, because airline travel is much more efficient then car travel, which is your other alternative unless someone wants to actually build high-speed rail.
- klodolph 4y ago
  Biofuel is not a solution. Not now, at least. It’s just so damn inefficient, you are better off with an oil well, if you care about the environment. Airline travel is only better than cars if you compare it to a 1-passenger car, and then ignore anything other than CO2 emissions. It’s pretty bad.
  - MichaelZuo 4y ago
    I've always thought a carbon credit/tax, or more broadly an externality credit/tax, system, would resolve these issues. Then the users will pay the real cost always, and obviates the need to ponder.
    - HPsquared 4y ago
      That works until governments realize they have an incentive to maximize environmental damage so they can bring in more tax. There is the risk of the same old game (never solve a problem so that it can be "managed" forever)
      - MichaelZuo 4y ago
        The incentive wouldn't be any greater then forcing fuel users to consume as much fuel as possible to bring in more tax.
    - echelon 4y ago
      > an externality credit/tax, system, would resolve these issues. This is a good approach to a lot of things, except when said thing also has positive externalites and second order effects associated with it. Travel is one such example, as it's essential to lubricate the economy. As such, we should encourage as much of it as possible. Business thrives on it. Without cheap air travel, America is weak. We lack commuter rail infrastructure, and car travel is far too slow. Taxing air travel or increasing its costs are a nonstarter. If we predicted the era of air travel to be coming to an end, we'd be making rail investments. Air travel is likely to continue growing, however, so there's little rush for domestic rail projects. America flies.
  - XorNot 4y ago
    Perhaps you'd like to explain some of those considerations rather then just waving at them. Modern jet turbines are running within a few % of maximum thermodynamic efficiency. So what consequences other then CO2 emissions are worse then anything else? And for that matter, how would biofuels possibly be worse fossil fuels, given that the whole point is to not emit net CO2 into the atmosphere. Obviously it's "efficient" because all the energy we put in has to come from the sun, rather then obtained for free but that's the point.
    - jabl 4y ago
      > Modern jet turbines are running within a few % of maximum thermodynamic efficiency. Indeed they are marvels of engineering. But that doesn't make them "sustainable". It just takes a lot of energy to push something through the air at high speed, no matter how efficient the engines are. Apart from the CO2 emissions, there's also the issue of the GHG forcing effect of high altitude water vapor emissions. Current estimates are that flight at typical airliner altitudes of ~10 km results in a GHG forcing (over some decades) of roughly 3 times more than burning the same fuel on the ground. > And for that matter, how would biofuels possibly be worse fossil fuels, given that the whole point is to not emit net CO2 into the atmosphere. Obviously it's "efficient" because all the energy we put in has to come from the sun, rather then obtained for free but that's the point. The major issue is due to land use changes. Biodiversity is already in a sharp decline (arguably this is an as big, if not bigger issue than climate change), largely driven by converting nature into cropland. Secondly, converting nature into crops, whether for fuel or food, tends to result in large CO2 emissions due to the carbon that has been stored into the soils being released. And finally, biofuels just don't scale. There isn't enough arable land on the planet to replace the amount of fossil fuels we use today.
    - HPsquared 4y ago
      Farming causes environmental damage besides greenhouse emissions. Even discounting all the other forms of environmental damage, a lot of biofuel schemes (e.g. corn ethanol) emit more greenhouse gases than they save.
    - klodolph 4y ago
      Thermodynamic efficiency is the wrong way to measure efficiency here. It makes no sense to measure efficiency that way, none at all. I’m talking about biofuels as they exist today, not as they hypothetically exist in the future. Currently, you burn biofuels, you end up releasing more CO2 into the atmosphere, because the production of biofuels produces CO2. It’s not negligible, either. All of the analyses I’ve seen of biofuel paint an incredibly dismal picture. As far as I can tell, the main strategy to reduce CO2 emissions is to stop burning fuels altogether, not switch to something like biofuel. Airplanes need power density & energy density in order to work which makes technologies like batteries unsuitable. Way easier to power something on the ground, where you’re not spending tons of energy just to keep it from crashing. Or better yet, on an electrified rail.
  - tehjoker 4y ago
    When people talk about biofuel as a replacement for oil (which needs to be replaced) I think of the scenes from Horizon Forbidden West where the AI killbot just sucks in all the life around it and leaves the landscape dead.
    - HPsquared 4y ago
      Climate policy is doing that anyway, no AI killbots required. It's just happening gradually. Think 'killjoy' not 'killbot'
      - tehjoker 4y ago
        This is true, but if we did try to sustain our current growth trajectory on biofuel, this would accelerate at a dizzying rate.
  - midoridensha 4y ago
    >Airline travel is only better than cars if you compare it to a 1-passenger car Why would you compare it with anything else? People don't actually fill their 5-8-person vehicles, almost ever, and certainly not on longer trips. I don't have any sources handy, but I'm pretty sure an airplane is significantly more fuel-efficient (which also means less CO2 output) per person for a NYC-LA trip than a gigantic pickup truck with even 2 people. Comparing air travel to a fully-occupied Prius is a ridiculous comparison, because Americans just don't ever drive that way. They drive huge trucks and SUVs and they drive them with 1, or at most, 2 people.
- D13Fd 4y ago
  > airline travel is much more efficient then car travel Sure, but for many business travelers, air travel isn’t competing with car travel. It’s competing with a nearly-zero-emissions Teams call or Zoom meeting.
- hannob 4y ago
  > because airline travel is much more efficient then car travel Citation needed. (FWIW It's wrong. It's also even more wrong if you consider future technologies, aka synthetic jet fuel vs. electric vehicles.)
- fulafel 4y ago
  It's possible (commercialy since ~1936) but that's not saying much.
mlindner 4y ago
> I doubt a vision of growth is compatible with "sustainability". In fact, I find it highly unlikely. This is a backwards viewpoint. A future of sustainable is a future of more consumption, but green consumption. Standard of living has a strong correlation with energy use. We'll only use more energy in the future. We're still a ways off from a Type 1 civilization.
- ciconia 4y ago
  > A future of sustainable is a future of more consumption, but green consumption. This is a common trope among the HN crowd. There's no such thing as green consumption. Consuming resources means pollution, whether it be CO2, toxic substances or other refuse from industrial processes. Manufacturing solar panels and wind turbines still means resource extraction which is polluting by definition. Oh, and by the way, we don't know how to mine for metals without using fossil fuels. What you call "green consumption" simply does not exist.
  - scrollaway 4y ago
    “Sustainable”: to “sustain”. It means that something is viable over a long period of time. Current practices in various industries and nations are unsustainable because they depend on conditions which are only possible over the short term. For example, cheap fossil fuels. Some other practices are unsustainable in the grand scheme of things, because they are partly responsible for an environment which is itself unsustainable. For example, costs externalised to the environment which has a delayed reaction of several decades. “Polluting” is not unsustainable by itself as long as you have a way to counterbalance it. You can have a sustainable system which extracts resources and exhausts co2. “Green” is worthless as an environmental adjective because it has whichever definition you want to apply to it. If you say “sustainable consumption”, though, there’s no problem creating that. Nature itself is a closed system of sustainable consumption.
  - ZeroGravitas 4y ago
    > we don't know how to mine for metals without using fossil fuels. What magical property of fossil fuels is needed to mine? Large mining corporations seem to be on the leading edge of decarbonisation. After all, who wants to ship fuel miles out into the desert and then burn it in an enclosed underground space when you can use solar panels and electric motors? If you're extra clever, you can actually generate electricity as you bring the heavy ore down to sea level.

XorNot 4y ago

You can synthesize jet fuel from CO2 and renewable energy. Or biologically derived products. These are all use cases where consumption won't outstrip capacity, because airline travel is much more efficient then car travel, which is your other alternative unless someone wants to actually build high-speed rail.

klodolph 4y ago
Biofuel is not a solution. Not now, at least. It’s just so damn inefficient, you are better off with an oil well, if you care about the environment. Airline travel is only better than cars if you compare it to a 1-passenger car, and then ignore anything other than CO2 emissions. It’s pretty bad.
- MichaelZuo 4y ago
  I've always thought a carbon credit/tax, or more broadly an externality credit/tax, system, would resolve these issues. Then the users will pay the real cost always, and obviates the need to ponder.
  - HPsquared 4y ago
    That works until governments realize they have an incentive to maximize environmental damage so they can bring in more tax. There is the risk of the same old game (never solve a problem so that it can be "managed" forever)
    - MichaelZuo 4y ago
      The incentive wouldn't be any greater then forcing fuel users to consume as much fuel as possible to bring in more tax.
  - echelon 4y ago
    > an externality credit/tax, system, would resolve these issues. This is a good approach to a lot of things, except when said thing also has positive externalites and second order effects associated with it. Travel is one such example, as it's essential to lubricate the economy. As such, we should encourage as much of it as possible. Business thrives on it. Without cheap air travel, America is weak. We lack commuter rail infrastructure, and car travel is far too slow. Taxing air travel or increasing its costs are a nonstarter. If we predicted the era of air travel to be coming to an end, we'd be making rail investments. Air travel is likely to continue growing, however, so there's little rush for domestic rail projects. America flies.
- XorNot 4y ago
  Perhaps you'd like to explain some of those considerations rather then just waving at them. Modern jet turbines are running within a few % of maximum thermodynamic efficiency. So what consequences other then CO2 emissions are worse then anything else? And for that matter, how would biofuels possibly be worse fossil fuels, given that the whole point is to not emit net CO2 into the atmosphere. Obviously it's "efficient" because all the energy we put in has to come from the sun, rather then obtained for free but that's the point.
  - jabl 4y ago
    > Modern jet turbines are running within a few % of maximum thermodynamic efficiency. Indeed they are marvels of engineering. But that doesn't make them "sustainable". It just takes a lot of energy to push something through the air at high speed, no matter how efficient the engines are. Apart from the CO2 emissions, there's also the issue of the GHG forcing effect of high altitude water vapor emissions. Current estimates are that flight at typical airliner altitudes of ~10 km results in a GHG forcing (over some decades) of roughly 3 times more than burning the same fuel on the ground. > And for that matter, how would biofuels possibly be worse fossil fuels, given that the whole point is to not emit net CO2 into the atmosphere. Obviously it's "efficient" because all the energy we put in has to come from the sun, rather then obtained for free but that's the point. The major issue is due to land use changes. Biodiversity is already in a sharp decline (arguably this is an as big, if not bigger issue than climate change), largely driven by converting nature into cropland. Secondly, converting nature into crops, whether for fuel or food, tends to result in large CO2 emissions due to the carbon that has been stored into the soils being released. And finally, biofuels just don't scale. There isn't enough arable land on the planet to replace the amount of fossil fuels we use today.
  - HPsquared 4y ago
    Farming causes environmental damage besides greenhouse emissions. Even discounting all the other forms of environmental damage, a lot of biofuel schemes (e.g. corn ethanol) emit more greenhouse gases than they save.
  - klodolph 4y ago
    Thermodynamic efficiency is the wrong way to measure efficiency here. It makes no sense to measure efficiency that way, none at all. I’m talking about biofuels as they exist today, not as they hypothetically exist in the future. Currently, you burn biofuels, you end up releasing more CO2 into the atmosphere, because the production of biofuels produces CO2. It’s not negligible, either. All of the analyses I’ve seen of biofuel paint an incredibly dismal picture. As far as I can tell, the main strategy to reduce CO2 emissions is to stop burning fuels altogether, not switch to something like biofuel. Airplanes need power density & energy density in order to work which makes technologies like batteries unsuitable. Way easier to power something on the ground, where you’re not spending tons of energy just to keep it from crashing. Or better yet, on an electrified rail.
- tehjoker 4y ago
  When people talk about biofuel as a replacement for oil (which needs to be replaced) I think of the scenes from Horizon Forbidden West where the AI killbot just sucks in all the life around it and leaves the landscape dead.
  - HPsquared 4y ago
    Climate policy is doing that anyway, no AI killbots required. It's just happening gradually. Think 'killjoy' not 'killbot'
    - tehjoker 4y ago
      This is true, but if we did try to sustain our current growth trajectory on biofuel, this would accelerate at a dizzying rate.
- midoridensha 4y ago
  >Airline travel is only better than cars if you compare it to a 1-passenger car Why would you compare it with anything else? People don't actually fill their 5-8-person vehicles, almost ever, and certainly not on longer trips. I don't have any sources handy, but I'm pretty sure an airplane is significantly more fuel-efficient (which also means less CO2 output) per person for a NYC-LA trip than a gigantic pickup truck with even 2 people. Comparing air travel to a fully-occupied Prius is a ridiculous comparison, because Americans just don't ever drive that way. They drive huge trucks and SUVs and they drive them with 1, or at most, 2 people.
D13Fd 4y ago
> airline travel is much more efficient then car travel Sure, but for many business travelers, air travel isn’t competing with car travel. It’s competing with a nearly-zero-emissions Teams call or Zoom meeting.
hannob 4y ago
> because airline travel is much more efficient then car travel Citation needed. (FWIW It's wrong. It's also even more wrong if you consider future technologies, aka synthetic jet fuel vs. electric vehicles.)
fulafel 4y ago
It's possible (commercialy since ~1936) but that's not saying much.

mlindner 4y ago

> I doubt a vision of growth is compatible with "sustainability". In fact, I find it highly unlikely. This is a backwards viewpoint. A future of sustainable is a future of more consumption, but green consumption. Standard of living has a strong correlation with energy use. We'll only use more energy in the future. We're still a ways off from a Type 1 civilization.

ciconia 4y ago
> A future of sustainable is a future of more consumption, but green consumption. This is a common trope among the HN crowd. There's no such thing as green consumption. Consuming resources means pollution, whether it be CO2, toxic substances or other refuse from industrial processes. Manufacturing solar panels and wind turbines still means resource extraction which is polluting by definition. Oh, and by the way, we don't know how to mine for metals without using fossil fuels. What you call "green consumption" simply does not exist.
- scrollaway 4y ago
  “Sustainable”: to “sustain”. It means that something is viable over a long period of time. Current practices in various industries and nations are unsustainable because they depend on conditions which are only possible over the short term. For example, cheap fossil fuels. Some other practices are unsustainable in the grand scheme of things, because they are partly responsible for an environment which is itself unsustainable. For example, costs externalised to the environment which has a delayed reaction of several decades. “Polluting” is not unsustainable by itself as long as you have a way to counterbalance it. You can have a sustainable system which extracts resources and exhausts co2. “Green” is worthless as an environmental adjective because it has whichever definition you want to apply to it. If you say “sustainable consumption”, though, there’s no problem creating that. Nature itself is a closed system of sustainable consumption.
- ZeroGravitas 4y ago
  > we don't know how to mine for metals without using fossil fuels. What magical property of fossil fuels is needed to mine? Large mining corporations seem to be on the leading edge of decarbonisation. After all, who wants to ship fuel miles out into the desert and then burn it in an enclosed underground space when you can use solar panels and electric motors? If you're extra clever, you can actually generate electricity as you bring the heavy ore down to sea level.