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Keep in mind that as a fraction of emissions, air travel is actually quite small, about 2-3% [1] (and this is from a harsh article). There's some concern that a

by entee 7y ago

Keep in mind that as a fraction of emissions, air travel is actually quite small, about 2-3% [1] (and this is from a harsh article). There's some concern that as the industry grows (roughly 5% a year) and other sectors decarbonize, air travel will consume a larger fraction of remaining "carbon budget" (25-50% depending on where you look). Clearly as the denominator shrinks, and the numerator grows even slowly, percentage increases. That said, it's probably not the main issue in in climate change or even close to it. Other sectors such as ground transport, industrial heat (cement, steel etc.), agriculture (primarily fertilizer) and other fixed sources (buildings/homes) are a bigger deal. If we end up with airlines as the last carbon source, that's probably OK if we deal with the rest. 25% or even 50% of remaining budget is fine if the rest of the (easier) problems get solved. Air travel is uniquely hard, let's get the easier stuff first. [1] https://www.nytimes.com/2019/09/19/climate/air-travel-emissions.html https://www.nytimes.com/2019/09/19/climate/air-travel-emissi...

Symmetry 7y ago
It's true that, overall, air travel isn't a large fraction of our carbon emissions. But that's entirely do to that fact that most people don't fly. Every trip you make across the Atlantic and back takes about 10% of a typical American's yearly carbon emissions. If you're a typical person who doesn't fly then indeed it's not worth worrying about the flying that other people are doing. But if you're someone who flies every year or especially multiple times a year then cutting down is probably one of the most significant things you can do for the environment.
- entee 7y ago
  How many of those trips are cuttable? Maybe one or two business trips. And businesses would already rather teleconference these days if the trip is really avoidable. Given how cumbersome and expensive flying is already, I'm not sure there's a huge amount of "waste" in the system to cut at the moment. As for the occasional personal trip (I assume by # of people though maybe not # of miles flown, the far more common use case, only 12% of passengers are business travel[1]), should we be telling people, "no you're not going to see grandma for christmas"? [1] https://www.investopedia.com/ask/answers/041315/how-much-revenue-airline-industry-comes-business-travelers-compared-leisure-travelers.asp https://www.investopedia.com/ask/answers/041315/how-much-rev...
  - NortySpock 7y ago
    "Environmental conservation by telling people to use less resources is like telling people not to sin. The problem is that Christians have been telling people not to sin for 2000 years, and people have not stopped sinning..."
  - nicoburns 7y ago
    I'd imagine a lot of them are cuttable. I have a friend who regularly flies to the US (from the UK) to run conferences. Frankly it's ridiculous that they don't hire someone from the US to so it. With modern video calling technology, how many business trips are really essential? Some sure, but a lot could be cut, or merged into fewer longer trips.
    - entee 7y ago
      You're right I think some are overdone. One example is the consultants taking a plane 2x a week (leave early monday, come back thursday eve, often with unconstrained distances). Maybe a bunch of those could be cut, though in that case I think a lot of these business models offer a "premium" service. If you're paying $1M/quarter for a McKinsey contract or for an I-banker or a big 4 accountant you definitely want to see that person physically. Though keep in mind McKinsey is also probably less price sensitive than the average flyer. Still even with that, I'd like to better understand the economics. If only 12% of trips are business vs pleasure, killing all business trips won't move the needle in the long run. There's some question of how long business trips are, you can be 12% of trips but if they're longer it's worse. My overall point is that there are a lot of factors in how people chose to travel. It's far from clear that increasing the already quite high price is what's going to deter people unless you tax it massively. In which case we'll effectively return to a situation like the pre-deregulation days where only the rich flew, which may be fine, but should be directly considered.
jellicle 7y ago
3% of global emissions being due to air travel, when 4/5 of the world population has never set foot in an airplane, is incredibly huge, not quite small. This is an activity almost entirely engaged in by the very wealthy, that has a huge adverse effect on the planet. Taxing air travel to reduce frivolous trips would be a great policy. Add fast trains between major US cities.
- svara 7y ago
  What you say isn't wrong, but when you're asking what the most impactful changes to the current system would be, the absolute climate impact of flying vs. other sources of greenhouse gases needs to be considered. Which is to say, the world-wide policy priorities need to be on transportation (other than flying), electricity production and industrial emissions [0]. Giving up coal and petrol cars has potentially much greater impact than giving up flying. That said, when you consider the CO2 emissions that you cause yourself directly, a good rule of thumb is that as soon as you fly at all, CO2 from flying dwarfs all your other CO2 emissions. On the individual level, not flying, flying less, or offsetting carbon emissions from flying has the biggest impact. [0] https://www.epa.gov/ghgemissions/sources-greenhouse-gas-emissions https://www.epa.gov/ghgemissions/sources-greenhouse-gas-emis...
  - bouncycastle 7y ago
    I think reducing CO2 emissions from a personal level is the wrong way to go about it. It needs to be addressed from a more higher level, because the majority of CO2 emissions cannot be attributed to a single person. Take for example shipping, which uses 4.5% of global co2 emissions, yet most people haven't stepped on a ship in their lifetime, and never will! Quote: "annual emissions from the world's merchant fleet have already reached 1.12bn tonnes of CO2, or nearly 4.5% of all global emissions" https://www.theguardian.com/environment/2008/feb/13/climatechange.pollution https://www.theguardian.com/environment/2008/feb/13/climatec... Also, note that aircraft are not limited to carrying passengers... They also carry cargo.
    - BurnGpuBurn 7y ago
newnewpdro 7y ago
In terms of impact there's a generally accepted ~2.7X multiplier applied to flight emissions: "Among the reasons for this focus is that these emissions, because they are made at high altitude, have a climate impact that is commonly estimated to be 2.7 higher than the same emissions if made at ground-level." [0] So you can look at 2-3% of co2, or you can look at impact and if we use the co2 proportion as a proxy of overall emissions, ~8% in terms of impact - and growing fast. https://en.wikipedia.org/wiki/Hypermobility_(travel) https://en.wikipedia.org/wiki/Hypermobility_(travel)
- iso1210 7y ago
  I wonder what the emissions from a methane powered suborbital BFR is compared with a 16 hour flight, especially if that methane was generated from CO2 extraction from the air using renewable sources of electricity.

by entee 7y ago

Symmetry 7y ago

It's true that, overall, air travel isn't a large fraction of our carbon emissions. But that's entirely do to that fact that most people don't fly. Every trip you make across the Atlantic and back takes about 10% of a typical American's yearly carbon emissions. If you're a typical person who doesn't fly then indeed it's not worth worrying about the flying that other people are doing. But if you're someone who flies every year or especially multiple times a year then cutting down is probably one of the most significant things you can do for the environment.

entee 7y ago
How many of those trips are cuttable? Maybe one or two business trips. And businesses would already rather teleconference these days if the trip is really avoidable. Given how cumbersome and expensive flying is already, I'm not sure there's a huge amount of "waste" in the system to cut at the moment. As for the occasional personal trip (I assume by # of people though maybe not # of miles flown, the far more common use case, only 12% of passengers are business travel[1]), should we be telling people, "no you're not going to see grandma for christmas"? [1] https://www.investopedia.com/ask/answers/041315/how-much-revenue-airline-industry-comes-business-travelers-compared-leisure-travelers.asp https://www.investopedia.com/ask/answers/041315/how-much-rev...
- NortySpock 7y ago
  "Environmental conservation by telling people to use less resources is like telling people not to sin. The problem is that Christians have been telling people not to sin for 2000 years, and people have not stopped sinning..."
- nicoburns 7y ago
  I'd imagine a lot of them are cuttable. I have a friend who regularly flies to the US (from the UK) to run conferences. Frankly it's ridiculous that they don't hire someone from the US to so it. With modern video calling technology, how many business trips are really essential? Some sure, but a lot could be cut, or merged into fewer longer trips.
  - entee 7y ago
    You're right I think some are overdone. One example is the consultants taking a plane 2x a week (leave early monday, come back thursday eve, often with unconstrained distances). Maybe a bunch of those could be cut, though in that case I think a lot of these business models offer a "premium" service. If you're paying $1M/quarter for a McKinsey contract or for an I-banker or a big 4 accountant you definitely want to see that person physically. Though keep in mind McKinsey is also probably less price sensitive than the average flyer. Still even with that, I'd like to better understand the economics. If only 12% of trips are business vs pleasure, killing all business trips won't move the needle in the long run. There's some question of how long business trips are, you can be 12% of trips but if they're longer it's worse. My overall point is that there are a lot of factors in how people chose to travel. It's far from clear that increasing the already quite high price is what's going to deter people unless you tax it massively. In which case we'll effectively return to a situation like the pre-deregulation days where only the rich flew, which may be fine, but should be directly considered.

jellicle 7y ago

3% of global emissions being due to air travel, when 4/5 of the world population has never set foot in an airplane, is incredibly huge, not quite small. This is an activity almost entirely engaged in by the very wealthy, that has a huge adverse effect on the planet. Taxing air travel to reduce frivolous trips would be a great policy. Add fast trains between major US cities.

svara 7y ago
What you say isn't wrong, but when you're asking what the most impactful changes to the current system would be, the absolute climate impact of flying vs. other sources of greenhouse gases needs to be considered. Which is to say, the world-wide policy priorities need to be on transportation (other than flying), electricity production and industrial emissions [0]. Giving up coal and petrol cars has potentially much greater impact than giving up flying. That said, when you consider the CO2 emissions that you cause yourself directly, a good rule of thumb is that as soon as you fly at all, CO2 from flying dwarfs all your other CO2 emissions. On the individual level, not flying, flying less, or offsetting carbon emissions from flying has the biggest impact. [0] https://www.epa.gov/ghgemissions/sources-greenhouse-gas-emissions https://www.epa.gov/ghgemissions/sources-greenhouse-gas-emis...
- bouncycastle 7y ago
  I think reducing CO2 emissions from a personal level is the wrong way to go about it. It needs to be addressed from a more higher level, because the majority of CO2 emissions cannot be attributed to a single person. Take for example shipping, which uses 4.5% of global co2 emissions, yet most people haven't stepped on a ship in their lifetime, and never will! Quote: "annual emissions from the world's merchant fleet have already reached 1.12bn tonnes of CO2, or nearly 4.5% of all global emissions" https://www.theguardian.com/environment/2008/feb/13/climatechange.pollution https://www.theguardian.com/environment/2008/feb/13/climatec... Also, note that aircraft are not limited to carrying passengers... They also carry cargo.
  - BurnGpuBurn 7y ago

newnewpdro 7y ago

In terms of impact there's a generally accepted ~2.7X multiplier applied to flight emissions: "Among the reasons for this focus is that these emissions, because they are made at high altitude, have a climate impact that is commonly estimated to be 2.7 higher than the same emissions if made at ground-level." [0] So you can look at 2-3% of co2, or you can look at impact and if we use the co2 proportion as a proxy of overall emissions, ~8% in terms of impact - and growing fast. https://en.wikipedia.org/wiki/Hypermobility_(travel) https://en.wikipedia.org/wiki/Hypermobility_(travel)

iso1210 7y ago
I wonder what the emissions from a methane powered suborbital BFR is compared with a 16 hour flight, especially if that methane was generated from CO2 extraction from the air using renewable sources of electricity.