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> The root problem with this aircraft is that people prefer cheaper flights over faster flights. Agreed. And that's not even mentioning the climate angle of i
by haberman 8y ago
> The root problem with this aircraft is that people prefer cheaper flights over faster flights.
Agreed. And that's not even mentioning the climate angle of it.
I've done some reading lately about the effects of air travel on climate. I was very depressed by what I found. Basically, air travel is terrible for global warming. Besides emissions of greenhouse gasses CO2 and NOx, the trails of water vapor ("contrails") form cirrus clouds that contribute to warming.
Unlike the electric car, there is no emerging technology that can save air travel from this environmental impact. Meanwhile, air travel is growing at ~5%/year. At this rate, by mid-century air travel alone will consume the world's entire emissions allowance, if we want to keep global warming to 2 °C or less. And supersonic travel appears to be even worse for the climate.
For all the talk about fighting global warming, I almost never hear about this. It seems like the most inconvenient truth of all: if we want to fight global warming, we have to fly less. This is a hard pill to swallow. Tesla is built on the idea that we can have cleaner cars without having to give up anything (because electric cars can be luxury items). But electric airplanes exist only as research curiosities -- they aren't up to the task of their fuel-burning counterparts. Right now it looks like the democratization of fast, world-wide travel might be a late 20th - early 21st century phenomenon that we can't get back. :(
- foolfoolz 8y agomight be an unpopular prediction on this board but i believe climate change will be solved by technology and not reduced consumption. electricity generation also has significant environmental impact and is not a solution in itself
- haberman 8y agoI very much want to believe this. But how?
- tormeh 8y agoIt cannot be achieved through reduced consumption. Humans won't allow it. It's technology or bust.
- zzzeek 8y agoI think the idea is that humanity itself dies off in large numbers due to lack of food, potable water, wars, etc. There's how you get your reduced consumption. The earth itself is just fine with this natural cycle.
- xenophonf 8y agoHere's your technological solution: Use more efficient, less polluting (and slower) turbofan engines instead of less efficient, more polluting (and faster) turbojects. And here's the attendant public policy: Tax the turbojects' users enough to offset the negative ecological externalities incurred by their use. That will likely make commercial SST unprofitable.
- MayeulC 8y agoAs far as I know, and according to Wikipedia, most commercial airliners already use turbofans [1], which are high-bypass turbojets [2]. Unless you were referring to turboprops? [1]: https://en.wikipedia.org/wiki/Turbofan https://en.wikipedia.org/wiki/Turbofan
- jandrese 8y agoAlmost nobody uses turbojets anymore. Certainly not airliners. Even fighter jets use turbofans.
- xenophonf 8y agoExactly my point.
- larkeith 8y ago> electricity generation also has significant environmental impact Hydropower? The primary materials used are concrete and steel, and dams last for centuries with minimal upkeep. As long as appropriate measures (such as fish ladders) are taken, the local and global environmental impact is negligible.
- gascan 8y agoMaybe, but we at least need to buy time until we otherwise solve the problems using technology.
- jadedhacker 8y agoHow much energy does it take to turn CO2 back into oil? Is there a viable synthesis pathway? Carbon neutral oil would be fabulous. I'm guessing you have to spend a significant amount of energy to turn it back into oil, but is it 1.01x? 1.5x? 10x? 200x? The lower range would be viable to work with other kinds of renewables. Can't store solar at night? Turn atmospheric carbon into oil. It doesn't have to be cheaper than oil (it almost certainly can't be unless it gets too hard to drill), but we can subsidize it within some kind of range. EDIT: Oh cool, some people are trying this. https://www.technologyreview.com/s/407748/making-gasoline-from-carbon-dioxide/ https://www.technologyreview.com/s/407748/making-gasoline-fr... https://www.sciencemag.org/news/2015/09/feature-there-s-too-much-carbon-dioxide-air-why-not-turn-it-back-fuel https://www.sciencemag.org/news/2015/09/feature-there-s-too-...
- solidr53 8y ago> But there is no electric airplane. Not for consumer use, but they exist. https://en.wikipedia.org/wiki/Electric_aircraft https://en.wikipedia.org/wiki/Electric_aircraft
- haberman 8y agoI didn't know that! I'll update my comment.
- simonrobb 8y agoIncidentally Uber (who are developing electric air taxis with Embraer, et al) are live streaming their annual summit on the topic starting tomorrow. https://www.uber.com/info/elevate/summit/ https://www.uber.com/info/elevate/summit/
- baxtr 8y agoDo I understand you correctly that if we would stop flying right now, we could reverse some effects of global warming (the water vapor part of it would be gone instantly)?
- hammock 8y ago>the water vapor part of it would be gone instantly Not to mention the parts of the economy that rely on air travel ;)
- airstrike 8y agoNot to mention the remaining parts of the economy which would grind to a halt even if not directly related to air travel
- merpnderp 8y agoYou don't have to to stop flying, only stop flying so high. Low level cloud cover has a massive net cooling effect.
- Tloewald 8y agoProblem is planes don't fly high for fun, they fly high because the air is thinner up high which improves fuel economy.
- scrumper 8y agoJet engines are massively more efficient at high altitude. Turbulence is much worse at lower altitude. Safety margins are reduced at lower altitude. Winds are far less predictable at lower altitude.
- loeg 8y ago> For all the talk about fighting global warming, I almost never hear about this. It seems like the most inconvenient truth of all: if we want to fight global warming, we have to fly less. I don't know what circles you hang out in, but I've heard this many times. The focus is on road vehicles and land power consumption because that's where the low hanging fruit is. And airlines do already have a profit motivation to decrease fuel consumption, which equates to reduced emissions. I'd like to see a CO2 tax to help align incentives. Cleaner burning fuels might be an option at some point. > But there is no electric airplane. (I assume you're talking about commercial airplanes. Electric airplanes do exist, but have limited range and/or speed, and thus limited commercial application, due to reduced energy density.) That could change, if batteries get a lot cheaper and lighter. Or you know, kerosene gets more expensive (government-enforced pricing of the externality of CO2 emission). Some of both. It's obviously more viable for short-haul flights than long-haul, but even that would help.
- selectodude 8y ago>That could change, if batteries get a lot cheaper and lighter. The batteries could be free. Until they literally burn up so the plane can get lighter and therefore can land, it's pretty much a non-starter for anything over a few hundred miles. The max takeoff weight of a Boeing 787 is 50 tons more than it's maximum landing weight, which will probably damage the gear in some capacity.
- jahabrewer 8y ago> The max takeoff weight of a Boeing 787 is 50 tons more than it's maximum landing weight I honestly don't know, but could this be part of the design simply because the engineers know the plane will weigh less on landing? Seems like that design would change if so much mass from fuel was no longer lost/burnt.
- selectodude 8y agoThe stronger the gear needs to be, the heavier it becomes. Planes are optimized for safety first and foremost, but weight is a very close second. Heavier plane = more batteries = more weight = more batteries etc.
- merpnderp 8y agoThis isn't even remotely true: "Unlike the electric car, there is no emerging technology that can save air travel from this environmental impact." Something as simple as flying low enough to create low level cloud cover would more than reverse the net effect of NOx and CO2 produced by planes. It's just more expensive because it takes longer and consumes more fuel.
- haberman 8y agoDo you have any references for this? I couldn't find any mention of this in my research. For example it's not mentioned here: https://en.wikipedia.org/wiki/Environmental_impact_of_aviation#Scope_for_improvement https://en.wikipedia.org/wiki/Environmental_impact_of_aviati...
- felipelemos 8y agoI'm yet to find someone who doesn't ever fly at least once because of the environment.
- tonyedgecombe 8y agoI don't, I stopped about twenty years ago once I became aware of the damage it was causing.
- paulcole 8y ago> if we want to fight global warming, we have to fly less Most people prefer to say they want to fight global warming as opposed to actually doing anything. If the average person really wanted to fight climate change, they'd: • Stop eating meat • Buy as few new items as possible • Never get on an airplane again • Not have kids And even then one person's actions really can't do a damn thing so who can blame them for just enjoying their life and doing whatever they want?
- adamsea 8y ago.... also get more politically active as it’s government policy which will probably have the most impact (such as a carbon tax).
- nradov 8y agoThe most viable long term solution for long-haul air transport will probably be carbon-neutral liquid fuels. For example, in principle it could eventually become possible to genetically engineer algae which pulls CO2 out of the air and produces kerosene.
- jjoonathan 8y agoEventually? In principle? Ethanol is a thing, just not one that was able to compete without taxing its competitors' externalities. Not sure how the math works out for jet engines, but I suspect it works out better than batteries.
- ams6110 8y agoEthanol could fuel a jet engine, but kerosene has a higher energy density. Ethanol production doesn't tend to be carbon neutral either, though maybe it's closer than petroleum pumped out of the ground.
- jjoonathan 8y agoMaybe it's better than petroleum? The hell? It's not only better, EtOH becomes entirely neutral in the limit where it takes over. The carbon released from burning all comes from the plant, which in turn all comes from the air. All other carbon costs are incidental (e.g. it doesn't make sense to immediately convert transportation, farming, and production equipment) or one-off and amortizable (ploughing fields).
- nradov 8y agoFor long haul air transport we would have to redesign engines, fuel systems, and airport infrastructure to use ethanol safely. And even then it would make flying less efficient because ethanol contains less energy. Synthetic kerosene or something similar would be an easier transition and give better results.
- Scramblejams 8y agoAviation is a sideshow. It accounts for around 2-4% of carbon, depending on how you count its impact. And be careful extrapolating today's trends into a straight line, it rarely works out that way. You could stop the world from flying tomorrow and it wouldn’t make a dent in your PPM growth. If aviation busts the carbon budget, so will most everything else, and by vastly larger margins. Better to direct your limited resources at lower hanging fruit, unless you'd prefer the perfect to kill the good.
- scythe 8y agoAircraft fuel can be carbon neutral, if the fuel is made by CO2 reduction (CO2 to methanol/methane and Fischer-Tropsch). It's just not economical today. CO2 reduction will never compete with electric cars, because it's just too inefficient, but for aircraft, even throwing away 2/3 of your input energy might make economic sense if that energy is clean.