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It states that half of aircraft pollution is from contrails made of aircraft soot. I’d like to see the literature and discovery of aircraft soot. As an engine

It states that half of aircraft pollution is from contrails made of aircraft soot. I’d like to see the literature and discovery of aircraft soot. As an engineer who has built aircraft, I find this fascinating. I would like to measure my amount of soot. How does one go about measuring how much soot I have? Obviously if my exhaust ports are black that’s bad but I’m genuinely curious about this as I’ve always assumed “black smoke bad, white smoke ok”. As for contrails, disturbing the atmosphere is going to cause some freezing (clouds) at that altitude, at that temperature. How do you suggest we mitigate that? Fly lower and burn more fuel? Fly less and tell people to take the train or that their package will arrive next week?

ant6n 10mo ago
Night trains
- baobun 10mo ago
  What would make you say such a thing?
roxolotl 10mo ago
Fly less. Is waiting a week for a package really that big of a deal? Is traveling less really that much to ask? It’s totally ok to be skeptical of the claims. I can’t make a judgement on them as I know even less than you might. But that’s not a reason to doubt that human’s environment impact matters and that maybe part of the solution is for those of us with access to 2day delivery for everything and cheap flights live a teeny bit more like those who don’t.
- harddrivereque 10mo ago
  It is easy to suggest to fly less but it is going to be impossible to convince society where core values include agressive "extra" consumption, which in turn is the backbone of the world's current economy. Flying is one of top "extra" consumption types out there. I know many people are trying to convince people of that, but the society is moving in the opposite direction - bigger cars (both us and eu), more travel. Maybe arguments used currently are not convincing enough? I mean, sure, keep trying and you will obviously reach a certain 0.00x% of the population, but that's not really going to make any difference
  - JKCalhoun 10mo ago
    The general way to affect public habits (whether it works or not) is to apply a "sin tax" to that activity.
  - mavhc 10mo ago
    Just tax everything the amount it costs to clean up the pollution it causes, then use that money to clean up the pollution, now everything will have the correct price including externalities
- nQQKTz7dm27oZ 10mo ago
  [dead]
- nephihaha 10mo ago
  There is a big anti-tourism movement being built up across the world which is also being pushed by mass media. In Barcelona and Venice this has turned physical in a few instances. Flying is going to be made more expensive in the near future, I've no doubt of it. The environmental lobby will call for it. By the way, I have not flown for over a decade. I can't stand airports...
- counters 10mo ago
  The general point here is that your individual behavior as a consumer likely doesn't impact this mechanism. An aircraft doesn't skip a flight just because you waited a week to go on vacation. Aviation infrastructure is something of a fixed-cost which would likely only respond to systemic changes in travel demand, economic impacts on maintenance or fueling, or possibly some other form of regulation (e.g. a penalty for inducing contrails).
- zamalek 10mo ago
  > Is traveling less really that much to ask? I'm currently on dating apps and the amount of people who define their personalities by their travel habits is staggering.
  - chrneu 10mo ago
    lol thanks for saying this. "Travel" and "dogs" make up a crazy amount of dating profiles. Like 60% maybe? It's nuts. It's really weird. then you look at most of their profiles and it's the same handful of tourist photos or them paying to take a photo, basically. travel is just another status symbol thing to a lot of people. they do the same things they see on social media. it's weird. it's just another way of showing how much money you can spend on frivolous* stuff. "30 countries by 30" and stuff like that. the dog version of it is huskies. every one has a husky in their apartment. there are like 3-4 breeds that every woman in a city/urban area has. so weird. *not saying travel is frivolous. I'm saying the modern stereotypical version of it is very conforming and repetitive. the annoying thing is if someone were to ever say, in the real world, that maybe this version of travel isn't worth the damage to the environment, they would most likely get labeled an asshole or something. a "downer" or someone who is a "hater", or they are "ruining the vibe". more and more often "the vibe" is just an excuse to engage in crazy excess consumption that we label as "self care". lol sorry to go off on this. it's just so weird how we've twisted these things around as a culture/society.
somat 10mo ago
but contrails are not made of soot, where I define soot as dark unburned carbon, contrails actual are made of water. There is also a highly likely chance I am being to literal and the word choice of soot was a bit of poetic license on the part of the author. As a bonus consideration it might be better if they were made of soot, it would be ugly but water vapor is a tremendous greenhouse gas, several times as potent as CO2, soot blocking the sun might have more of a neutral effect, And related, we worked hard to get sulfur out of our fuels but sulfur dioxide turns out to be a negative greenhouse gas, it has a net cooling effect, I am not saying we should deliberately add sulfur back in, the downsides are too great, but it is an interesting bit of irony.
- bird0861 10mo ago
  The water is actually ice crystals and the ice crystals form around the soot.
  - wolttam 10mo ago
    There is also an immense amount of water vapour being produced by the combustion of a hydrocarbon.
    - counters 10mo ago
      Sure, but water vapor doesn't spontaneously transition to a liquid and accrete onto surfaces - there needs to be a super-saturation of water vapor, and given the temperatures of jet exhaust, that's not trivial to achieve. However, the super-saturation needed for water vapor to deposit onto surfaces as ice is much lower, hence the preference for ice crystal nucleation.
spuz 10mo ago
It does not state that half of aircraft pollution is from contrails. It says half of the climate impact of aviation is from contrails. Soot can have other effects and cause pollution in other ways such as reducing air quality but I suspect that is very minimal compared to other industries. The guide presented by the map gives a very good explanation on how contrail formation can be mitigating by altering the course of flights to reduce the formation in areas where it will have the most impact. This is based on a recent study that showed contrail avoidance could be one of the most cost-effective methods of reducing warming that we know of. https://iopscience.iop.org/article/10.1088/2634-4505/ad310c https://iopscience.iop.org/article/10.1088/2634-4505/ad310c Simon Clark did a good video on this recently: https://www.youtube.com/watch?v=QoOVqQ5sa08 https://www.youtube.com/watch?v=QoOVqQ5sa08
- reactordev 10mo ago
  >The CO2 emitted by aircraft only causes about half the climate impact of aviation. The other half comes from contrails— artificial clouds that are created by soot in the engine exhaust. Then what does that mean? I find it strange. Clouds happen naturally. Contrails are mini clouds (literally a cloud chamber), are we saying that all those “chemtrails” are pollution? Or are we saying the unspent fuel particulate inside that they formed around is? This is where this bizarro science is going off the deep end for me. As any object traveling through the atmosphere at that altitude, disrupting air, is going to form condensation and cloud trails. The more moisture in the atmosphere, the more trails. Sure there’s a little bit of unspent kerosene particles but hardly enough to even be a glycerin on a well working engine. Are we suggesting changing flight routes and wasting more fuel (which pollutes more) to protect the ground from these 0.0000001% reduction in light cloud trails? Seriously. I want to know the science behind how this plays out. I’m all for shutting down the black exhaust engines and cleaning up how we produce thrust. I’m all for that. This argument that clouds cause pollution is just wacky. What about wingtips. Those cause trails (though not as pronounced as the engines turning at 12,000rpm), those contain no particulates and yet, they exist. Atmospheric science can explain a lot of what you see at 30,000ft (10,000m). This all sounds like NIMBY science posturing and pseudo-science to me.
  - 10mo ago
tzs 10mo ago
> As for contrails, disturbing the atmosphere is going to cause some freezing (clouds) at that altitude, at that temperature. How do you suggest we mitigate that? Fly lower and burn more fuel? Fly less and tell people to take the train or that their package will arrive next week? See this article: https://www.technologyreview.com/2024/03/12/1089620/how-rerouting-planes-to-produce-fewer-contrails-could-help-cool-the-planet/ https://www.technologyreview.com/2024/03/12/1089620/how-rero... Here are some highlights, in case the paywall is a problem for some. First, how much do contrails matter? > This cirrus-forming phenomenon could account for around 35% of aviation’s total contribution to climate change—or about 1% to 2% of overall global warming, according to some estimates > A small fraction of overall flights, between 2% and 10%, create about 80% of the contrails. So the growing hope is that simply rerouting those flights could significantly reduce the effect, presenting a potentially high leverage, low cost and fast way of easing warming. Breakthrough Energy, Google Research, and American Airlines conducted a test: > They employed satellite imagery, weather data, software models, and AI prediction tools to steer pilots over or under areas where their planes would be likely to produce contrails. American Airlines used these tools in 70 test flights over six months, and subsequent satellite data indicated that they reduced the total length of contrails by 54%, relative to flights that weren’t rerouted Avoiding the contrail prone regions would use more fuel, so the question is how much would it cost to avoid those regions? > A new study published in Environmental Research: Infrastructure and Sustainability explored this issue by coupling commercial tools for optimizing flight trajectories with models that simulated nearly 85,000 American Airlines flights, both domestic and international, under various weather conditions last summer and this winter. > In those simulations, the researchers found that reducing the warming effect of contrails by 73% increased fuel costs by just 0.11% and overall costs by 0.08%, when averaged across those tens of thousands of flights. (Only about 14% of the flights needed to be adjusted to avoid forming warming contrails in the simulations.) There are also a couple of other factors to consider, such as: > There are also some thorny complications that still need to be resolved, like the fact that cirrus clouds can also reduce warming by reflecting away short-wave radiation from the sun. > The loss of this cooling effect would have to be tallied into any calculation of the net benefit—or, perhaps, avoided. For instance, Shapiro says the initial strategy might be to reroute flights only during the early evening and night, which would eliminate the sunlight-reflecting complication. Another one is the the increased fuel will add to CO2 to the atmosphere. CO2 stays in the atmosphere a lot longer than water, so it is possible that reducing contrails would be a net positive in the short term but a net negative over the long term.

ant6n 10mo ago

Night trains

baobun 10mo ago
What would make you say such a thing?

roxolotl 10mo ago

Fly less. Is waiting a week for a package really that big of a deal? Is traveling less really that much to ask? It’s totally ok to be skeptical of the claims. I can’t make a judgement on them as I know even less than you might. But that’s not a reason to doubt that human’s environment impact matters and that maybe part of the solution is for those of us with access to 2day delivery for everything and cheap flights live a teeny bit more like those who don’t.

harddrivereque 10mo ago
It is easy to suggest to fly less but it is going to be impossible to convince society where core values include agressive "extra" consumption, which in turn is the backbone of the world's current economy. Flying is one of top "extra" consumption types out there. I know many people are trying to convince people of that, but the society is moving in the opposite direction - bigger cars (both us and eu), more travel. Maybe arguments used currently are not convincing enough? I mean, sure, keep trying and you will obviously reach a certain 0.00x% of the population, but that's not really going to make any difference
- JKCalhoun 10mo ago
  The general way to affect public habits (whether it works or not) is to apply a "sin tax" to that activity.
- mavhc 10mo ago
  Just tax everything the amount it costs to clean up the pollution it causes, then use that money to clean up the pollution, now everything will have the correct price including externalities
nQQKTz7dm27oZ 10mo ago
[dead]
nephihaha 10mo ago
There is a big anti-tourism movement being built up across the world which is also being pushed by mass media. In Barcelona and Venice this has turned physical in a few instances. Flying is going to be made more expensive in the near future, I've no doubt of it. The environmental lobby will call for it. By the way, I have not flown for over a decade. I can't stand airports...
counters 10mo ago
The general point here is that your individual behavior as a consumer likely doesn't impact this mechanism. An aircraft doesn't skip a flight just because you waited a week to go on vacation. Aviation infrastructure is something of a fixed-cost which would likely only respond to systemic changes in travel demand, economic impacts on maintenance or fueling, or possibly some other form of regulation (e.g. a penalty for inducing contrails).
zamalek 10mo ago
> Is traveling less really that much to ask? I'm currently on dating apps and the amount of people who define their personalities by their travel habits is staggering.
- chrneu 10mo ago
  lol thanks for saying this. "Travel" and "dogs" make up a crazy amount of dating profiles. Like 60% maybe? It's nuts. It's really weird. then you look at most of their profiles and it's the same handful of tourist photos or them paying to take a photo, basically. travel is just another status symbol thing to a lot of people. they do the same things they see on social media. it's weird. it's just another way of showing how much money you can spend on frivolous* stuff. "30 countries by 30" and stuff like that. the dog version of it is huskies. every one has a husky in their apartment. there are like 3-4 breeds that every woman in a city/urban area has. so weird. *not saying travel is frivolous. I'm saying the modern stereotypical version of it is very conforming and repetitive. the annoying thing is if someone were to ever say, in the real world, that maybe this version of travel isn't worth the damage to the environment, they would most likely get labeled an asshole or something. a "downer" or someone who is a "hater", or they are "ruining the vibe". more and more often "the vibe" is just an excuse to engage in crazy excess consumption that we label as "self care". lol sorry to go off on this. it's just so weird how we've twisted these things around as a culture/society.

somat 10mo ago

but contrails are not made of soot, where I define soot as dark unburned carbon, contrails actual are made of water. There is also a highly likely chance I am being to literal and the word choice of soot was a bit of poetic license on the part of the author. As a bonus consideration it might be better if they were made of soot, it would be ugly but water vapor is a tremendous greenhouse gas, several times as potent as CO2, soot blocking the sun might have more of a neutral effect, And related, we worked hard to get sulfur out of our fuels but sulfur dioxide turns out to be a negative greenhouse gas, it has a net cooling effect, I am not saying we should deliberately add sulfur back in, the downsides are too great, but it is an interesting bit of irony.

bird0861 10mo ago
The water is actually ice crystals and the ice crystals form around the soot.
- wolttam 10mo ago
  There is also an immense amount of water vapour being produced by the combustion of a hydrocarbon.
  - counters 10mo ago
    Sure, but water vapor doesn't spontaneously transition to a liquid and accrete onto surfaces - there needs to be a super-saturation of water vapor, and given the temperatures of jet exhaust, that's not trivial to achieve. However, the super-saturation needed for water vapor to deposit onto surfaces as ice is much lower, hence the preference for ice crystal nucleation.

spuz 10mo ago

It does not state that half of aircraft pollution is from contrails. It says half of the climate impact of aviation is from contrails. Soot can have other effects and cause pollution in other ways such as reducing air quality but I suspect that is very minimal compared to other industries. The guide presented by the map gives a very good explanation on how contrail formation can be mitigating by altering the course of flights to reduce the formation in areas where it will have the most impact. This is based on a recent study that showed contrail avoidance could be one of the most cost-effective methods of reducing warming that we know of. https://iopscience.iop.org/article/10.1088/2634-4505/ad310c https://iopscience.iop.org/article/10.1088/2634-4505/ad310c Simon Clark did a good video on this recently: https://www.youtube.com/watch?v=QoOVqQ5sa08 https://www.youtube.com/watch?v=QoOVqQ5sa08

reactordev 10mo ago
>The CO2 emitted by aircraft only causes about half the climate impact of aviation. The other half comes from contrails— artificial clouds that are created by soot in the engine exhaust. Then what does that mean? I find it strange. Clouds happen naturally. Contrails are mini clouds (literally a cloud chamber), are we saying that all those “chemtrails” are pollution? Or are we saying the unspent fuel particulate inside that they formed around is? This is where this bizarro science is going off the deep end for me. As any object traveling through the atmosphere at that altitude, disrupting air, is going to form condensation and cloud trails. The more moisture in the atmosphere, the more trails. Sure there’s a little bit of unspent kerosene particles but hardly enough to even be a glycerin on a well working engine. Are we suggesting changing flight routes and wasting more fuel (which pollutes more) to protect the ground from these 0.0000001% reduction in light cloud trails? Seriously. I want to know the science behind how this plays out. I’m all for shutting down the black exhaust engines and cleaning up how we produce thrust. I’m all for that. This argument that clouds cause pollution is just wacky. What about wingtips. Those cause trails (though not as pronounced as the engines turning at 12,000rpm), those contain no particulates and yet, they exist. Atmospheric science can explain a lot of what you see at 30,000ft (10,000m). This all sounds like NIMBY science posturing and pseudo-science to me.
- 10mo ago

tzs 10mo ago

> As for contrails, disturbing the atmosphere is going to cause some freezing (clouds) at that altitude, at that temperature. How do you suggest we mitigate that? Fly lower and burn more fuel? Fly less and tell people to take the train or that their package will arrive next week? See this article: https://www.technologyreview.com/2024/03/12/1089620/how-rerouting-planes-to-produce-fewer-contrails-could-help-cool-the-planet/ https://www.technologyreview.com/2024/03/12/1089620/how-rero... Here are some highlights, in case the paywall is a problem for some. First, how much do contrails matter? > This cirrus-forming phenomenon could account for around 35% of aviation’s total contribution to climate change—or about 1% to 2% of overall global warming, according to some estimates > A small fraction of overall flights, between 2% and 10%, create about 80% of the contrails. So the growing hope is that simply rerouting those flights could significantly reduce the effect, presenting a potentially high leverage, low cost and fast way of easing warming. Breakthrough Energy, Google Research, and American Airlines conducted a test: > They employed satellite imagery, weather data, software models, and AI prediction tools to steer pilots over or under areas where their planes would be likely to produce contrails. American Airlines used these tools in 70 test flights over six months, and subsequent satellite data indicated that they reduced the total length of contrails by 54%, relative to flights that weren’t rerouted Avoiding the contrail prone regions would use more fuel, so the question is how much would it cost to avoid those regions? > A new study published in Environmental Research: Infrastructure and Sustainability explored this issue by coupling commercial tools for optimizing flight trajectories with models that simulated nearly 85,000 American Airlines flights, both domestic and international, under various weather conditions last summer and this winter. > In those simulations, the researchers found that reducing the warming effect of contrails by 73% increased fuel costs by just 0.11% and overall costs by 0.08%, when averaged across those tens of thousands of flights. (Only about 14% of the flights needed to be adjusted to avoid forming warming contrails in the simulations.) There are also a couple of other factors to consider, such as: > There are also some thorny complications that still need to be resolved, like the fact that cirrus clouds can also reduce warming by reflecting away short-wave radiation from the sun. > The loss of this cooling effect would have to be tallied into any calculation of the net benefit—or, perhaps, avoided. For instance, Shapiro says the initial strategy might be to reroute flights only during the early evening and night, which would eliminate the sunlight-reflecting complication. Another one is the the increased fuel will add to CO2 to the atmosphere. CO2 stays in the atmosphere a lot longer than water, so it is possible that reducing contrails would be a net positive in the short term but a net negative over the long term.