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Air Travel Emissions Vastly Outpace Predictions

nytimes.com

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Re: Air Travel Emissions Vastly Outpace Predictions

#181

Post by dredmorbius »

taylortrusty wrote: post #33
Symmetry wrote: post #6

Earlier quoted context omitted.

It depends on who you are. The median person doesn't fly. But a round trip flight from Shanghai to New York is 3.4 tons of carbon, pretty close to the average global anual per capita emissions of 4.0 tons.

You need to divide that 3.4 tons of carbon by the ~270 people on each flight

Aircraft use a lot of fuel.

Roughly half the takeoff weight of an airliner is fuel. The fuel burned on a continental-distance (3000+ km / 2000+ mile) flight is roughly equal to the passenger's weight. CO2 emissions by mass exceed the mass of the fuel by a factor of three, as you're adding the mass of the oxygen that's added, far more than the hydrogen that's split off.

https://www.engineeringtoolbox.com/co2-emission-fuels-d_1085...

For a 747, roughly, takeoff, climb and descent require a fixed share of fuel, 7840 kg, and take about 250km (30.1 kg/km), cruise, another 10.1 kg/km. Shorter flights are comparatively worse, but what gets you in long-haul flights is simply the total distance: about 12,000 km for each leg of that Shanghai-NYC trip. And that's allocated across about 420 passengers.

https://www.sciencefocus.com/future-technology/how-many-cars...

Back-of-the-envelope estimates: At Shanghai-NYC distances, that's 34,300 kg of fuel vs. about 420 * 100 kg/passenger total allowance (rough numbers), or roughly 3x the fuel mass per passenger, per leg, or 9x the CO2 emissions mass. That works out to about 1.8 tonnes based on my figures and maths, which is lower than your parent, but probably assumes too large a plane and too many passengers for a long-distance flight.

But yes: tonnes of CO2 emissions per passenger for round-trip international travel is about right.

Re: Air Travel Emissions Vastly Outpace Predictions

#182

Post by TheSpiceIsLife »

csallen wrote: post #158
TheSpiceIsLife wrote: post #88

Earlier quoted context omitted.

There are people who believe that is an essential course to chart because with out the will to change we are nothing. I’m not saying that is or isn’t my perspective, just pointing out that it is a perspective that may hold some validity.

Totally, and this is the perspective I'm responding to. I don't think it's necessarily invalid. But I do think it's very easy to get sucked into a mindset of, "Let's shame individuals into making sacrifices," without actually doing the math on whether or not that's an effective approach.

Yep, that’s it, shifting the Overton window to better practices.

Re: Air Travel Emissions Vastly Outpace Predictions

#183

Post by munificent »

misiti3780 wrote: post #2

"Over all, air travel accounts for about 2.5 percent of global carbon dioxide emissions — a far smaller share than emissions from passenger cars or power plants." 2.5% means we should focus on reducing somewhere else in the near term.

This depends entirely on the distribution of the other categories.

Look at this like optimizing a program. If you do a profile and one function takes up 80% of the profile and everything else is a tiny fraction, sure, focus on that hot spot. But if you have many many slow functions and none is a clear hotspot, they all need attention, even the 2.5% one.

Re: Air Travel Emissions Vastly Outpace Predictions

#184

Post by bt848 »

tempsy wrote: post #172
blunte wrote: post #136

If you need to travel long distances, there's little substitute for an airplane. If air travel accounts for less emissions than passenger cars, and if the top 15 polluting large container ships produce as much (noxious oxides of nitrogen and sulphur) pollution as all cars, then we need to fix shipping first. And if you look at a lot of the crap that is being shipped, it's stuff we just don't need. A lot of things are…

Surprised I haven't seen anyone mention Hyperloop yet. I think if any of the major Hyperloop companies are able to realize their vision then traveling city center to city center by Hyperloop would be a much preferable substitute to air travel for most intercontinental travel.

Even if Hypeloop worked, which hasn't been demonstrated, its nameplate capacity is close to zero. It can optimistically replace one highway lane. It cannot possibly displace air travel unless you have dozens of tubes. Each of the Bay Area's three airports averages about 3-4x the passengers that a hypeloop might be capable of moving, and that's averaged over the whole year. Peak day/hour air travel can never be replaced with hypeloop.

Ordinary steel-wheel high-speed rail can do it, though. There are many stations in the world that can move 100k pax/hour.

Re: Air Travel Emissions Vastly Outpace Predictions

#185

Post by jdc »

bt848 wrote: post #174
blunte wrote: post #136

If you need to travel long distances, there's little substitute for an airplane. If air travel accounts for less emissions than passenger cars, and if the top 15 polluting large container ships produce as much (noxious oxides of nitrogen and sulphur) pollution as all cars, then we need to fix shipping first. And if you look at a lot of the crap that is being shipped, it's stuff we just don't need. A lot of things are…

You seem to have conflated CO2 with other pollutants. All the world's shipping taken together amounts to only 3% of the carbon emission inventory. It certainly is not the case that 15 ships emit more carbon than all cars.

Where does the 3% figure come from? It's not clear to me that we have or are even trying to get accurate sea-based emissions inventory.

Re: Air Travel Emissions Vastly Outpace Predictions

#186

Post by noonespecial »

smt88 wrote: post #140
tombert wrote: post #86

I fly fairly frequently to California from NY for work, lately after reading a few articles like this, I wonder if I should put my foot down to my manager and tell them that I'm not going to anymore until flying is less terrible for the atmosphere. I don't think I'll be fired for that, and even if I were I'd probably be able to find another job without too much trouble at this point, but I feel a bit bad for people d…

Put your foot down if you can without any consequences. Otherwise, keep your (presumably) high-paying job and use your money on political donations. The invisible hand is not going to solve climate change.

Well, it will, but the way it does so is to wait a long time and then deliver the solution all at once as a giant slap to humanity's face.

Re: Air Travel Emissions Vastly Outpace Predictions

#187

Post by sp332 »

tempsy wrote: post #178
sp332 wrote: post #110

Earlier quoted context omitted.

Well there's a new low-sulphur fuel regulation coming into effect in a few months. http://www.imo.org/en/MediaCentre/PressBriefings/Pages/MEPC-... That will help with some of the pollution anyway.

That doesn't exactly solve the problem of cruise ships dumping raw waste into the ocean.

Of all the kinds of pollution, why worry about that? There's way more poop in the ocean already.

Re: Air Travel Emissions Vastly Outpace Predictions

#188

Post by Supermancho »

bt848 wrote: post #174
blunte wrote: post #136

If you need to travel long distances, there's little substitute for an airplane. If air travel accounts for less emissions than passenger cars, and if the top 15 polluting large container ships produce as much (noxious oxides of nitrogen and sulphur) pollution as all cars, then we need to fix shipping first. And if you look at a lot of the crap that is being shipped, it's stuff we just don't need. A lot of things are…

You seem to have conflated CO2 with other pollutants. All the world's shipping taken together amounts to only 3% of the carbon emission inventory. It certainly is not the case that 15 ships emit more carbon than all cars.

> It certainly is not the case that 15 ships emit more carbon than all cars.

That is correct. However, the pollutants that the referenced ships produce are far more hazardous (immediately) and in greater volumes than many countries produce (in aggregate) per year. To put it in perspective...warning: this is an analogy that mixes metaphors:

Talking about CO2 emissions while Nuclear Waste is constantly being pumped into the ocean is shuffling the deck chairs.

Re: Air Travel Emissions Vastly Outpace Predictions

#189

Post by ojagodzinski »

reaperducer wrote: post #180
Lramseyer wrote: post #168

One thing that's very important to keep in mind when looking at air travel emissions is how fuel efficient planes actually are. The math works out to around 100 miles per gallon per passenger. And at an underwhelming 2.5% of global emissions, I can't really put it in the category of "low hanging fruit." That's not to say that we shouldn't invest in things like high speed rail, (because we absolutely will see quality…

The math works out to around 100 miles per gallon per passenger. That assumes maximum passenger load, I assume. At maximum passenger load, my car gets 170 miles per gallon per passenger. A giant, gas-guzzling Chevy Suburban gets 198 miles per gallon per passenger. I don't think "per gallon per passenger" is a useful measure.

your car is full probably 5% of a time, airlines have profits from full planes, you don't.

"per gallon per passenger" is a useful measure for planes.

Re: Air Travel Emissions Vastly Outpace Predictions

#190

Post by sokoloff »

mehrdadn wrote: post #170
loeg wrote: post #157

Earlier quoted context omitted.

Price in the carbon and let consumers decide if they still need the travel. I expect a carbon offset tax wouldn't actually decrease air travel that much -- there's so much business travel that needs doing -- but it probably would slow down growth.

Definitely tax it, but I actually view a lot of the business travel as unnecessary compared to consumer travel, and that's what I'd want to get rid of first with a tax. I'm far more sympathetic to people trying to see their dying uncles or attend their sister's wedding or visiting their parents once a year than, say, professionals "needing" to attend conferences or whatever. Heck, come to think of it, if I ever saw a…

Vastly more business travel is done for sales or sales-support purposes than attending conference purposes.

Humans are tribal animals; we respond to communications in person better than over video conference and we tend to trust people with whom we've shared meals and drinks. Arguing that that just shouldn't be isn't likely to change anything about business behavior. I get on airplanes across oceans because it's effective. Believe me, I'd usually rather stay at home with my family and sleep in my own bed.

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