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Comment by dymk | Hacker News Reader

This is why we need a net carbon tax. Behavior won’t change unless people start paying the real cost of emitting carbon.

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Carbon tax only works if everyone agrees which is the actual crux of the issue. If you enforce new legislation to tax carbon-emitting industries in the US, all you are doing is offshoring that manufacturing to some place where the tax does not exist.

Not saying that it's inherently a bad idea, but there are no silver bullets on that issue. I'd like to see more work done on point source capture of carbon/methane. https://netl.doe.gov/carbon-management/carbon-capture

Air travel isn't something that can be offshored - if somebody in America wants to fly, they're getting on a plane in America, where an American carbon tax would apply.

Sure, it doesn't fix industries which can offshore, but it's a good place to start. Commercial air is a major source of carbon emissions.

My quick google says it's 2.5% of carbon emissions (for both passengers and cargo).

If we add a carbon tax, do you consider the prime benefit to be the reduction in demand (if it means 20% less air travel, that's .5% total global carbon emissions reduction)

Or do you feel like the prime benefit is to spur/incentivize more carbon neutral strategies (like electric aircraft?)?

Or, do you feel like the primary benefit would be the "offsets" (like protecting trees, carbon capture technology, etc)

I see a lot of talk about reducing carbon emissions, but it seems like there are a lot of things a "carbon tax" could change, and I feel like deciding on what one of those is the primary benefit is a harder problem than leveraging the tax in the first place.

Any type of reduction would be a huge deal. 0.5% net is more than most would dare to hope for.

Remember that each and every year we release more carbon in the atmosphere than the year before. So far with only one exception, during the covid lockdowns, but now we're back again with an even bigger increase than before.

Naive question: Are airliner emissions more harmful because they are further up in the atmosphere?

No they are not. Airliners fly in the lower stratosphere, the troposphere is what is primarily warming. The effects on ozone are another story.

[edit] for anyone downvoting, I'm referencing this paper[1] in the Encyclopedia of Global Environmental Change from 2002, which says:

> Increases of the concentration of small particles emitted from aircraft with similar residence times have also been measured near dense flight routes. CO2 on the other hand, has a lifetime of the order of 100 years and gets distributed essentially over the whole atmosphere. Therefore, the effects of CO2 emissions from aircraft are indistinguishable from the same quantity of CO2 emitted at the same time by any other source.

It's consistent with older research as well, and I can't find anything newer that refutes the claim.

[1] https://www.dlr.de/pa/en/Portaldata/33/Resources/dokumente/m...

I think your reasoning is correct for CO2, but the OP asked about "emissions" in general. For some of these, the dispersion is less, and thus the high altitude does make a difference. I've only skimmed it, but this seems to be a good paper describing the different effects: http://www.anjakollmuss.com/wp-content/uploads/2017/04/SEI_A...

While agreeing that a multiplier is not strictly correct, they recommend applying multiplier "greater than 2" to properly account for the non-CO2 effects of air traffic on global warming: Though science-based reasoning discourages the use of a simple multiplier to account for non-CO2 effects, such a multiplier is desirable from a policy and climate protection point of view. We elaborate on a number of scientific and value-related issues and conclude that a multiplier of 2 or greater should be used for air travel emissions calculators to account for non-CO2 warming effects.

Yeah I understood the OP to mean c02 and added the caveat about other emissions. It seems pretty uncertain, especially as lower level stratospheric mixing seems poorly understood. But, my understanding extends only as far as having read 3 papers on the topic.

From some googling, they lack catalytic converters, so the emissions they do put out are more harmful to the environment per-pound-produced than what comes out of a car's tailpipe.

Yes, they are, but not vastly. Air travel is still a small fraction of the average westerner's carbon footprint.

But aren't some of the emissions (sulfur based ones) significantly more harmful than pure CO2 released, and (from what I remember about Nathan Myhrvold's work) much more impactful when released at 40k feet? Just wondering if measuring the CO2 volume is less relevant when talking about releasing sulfurs at altitude.

Is that because the average westerner doesn’t fly every year?

How does it change if you only look at people who fly?

I'm talking about average, not median.

Ground transportation and home energy use and industrial energy use all dwarf the average flight emissions.

I’m asking about individuals.

I’ve flown a couple times this year. I’ve been airborne for about 20 hours. Are you saying my portion of the emissions from those flights is likely negligible compared to the emissions from owning a home and car?

Yes, actually, if you commute by car, or if you don't live in a ~fully-green energy state.

20 hours of flight is ~10,000 flight miles. A 737 gets ~80 mpg per passenger seat. Takeoff is an extra ~20% in an average flight's fuel consumption.

Or would in data claims air travel accounts for about 3.5% of carbon emissions.

https://ourworldindata.org/co2-emissions-from-aviation

We agree that that’s a huge amount, right?

In gross tonnage, yes sure.

I don't agree that 3.5% is a huge fraction.

You could tax the products on import though too

Yes, we need to have have international agreements negotiated in the united nations.

But it doesn't work if some of the most powerful countries think climate change does not even exist.

it's not that they don't believe in climate change -- that's a bit naive, tbh. it's that it's an incredibly weak bargaining position. the thinking goes like this: you care about the earth so much? then you cut back on your emissions. go ahead. that's the US's stance. it's the same stance Brazil uses re: deforestation & agricultural sprawl. they're negotiating in bad faith; they're not stupid.

the US in effect wants to be the last person to exit the room and turn off the lights. do you want them to move faster? then you need to get out of the room first. the smaller players need to stop pretending that they're the same size as the US, China, and India. That's just foolish wishful thinking. nobody's going to hold them accountable to environmental treaties or any carbon targets.

when everyone small leaves the room, then the US will shove the last remaining countries out before it, too. because it can. because you care more about the "environment" than they do, collectively.

That's exactly what negotiations and agreements are for. Nobody wants to cut emissions if the others are not chipping in too.

Paying taxes is annoying. Yet we need things like law enforcement or defense. So to make it happen, we agree on rules and then we enforce them on everyone. It wouldn't be possible if it was based on just altruism.

But we will never get there if leaders don't even admit it's a real thing happening. https://www.youtube.com/watch?v=UZq2L_49PBQ

A carbon tax with border adjustments already works if a couple of rich countries agree to do it.

Absolutely and utterly fictional. Carbon credit schemes are a way to push cost off and allow for corporations to pollute. Look at industrial pollutants and carbon is one of the least concerning. It's a political talking point why? Because lobbyists tell politicians they need it and hand them money.

Investigate a little deeper. You will find that the entire world must agree to participate for something like carbon tax to work... the world is not on board with hobbling industry

Best way to do it would be to tax anyone flying on PJs. You could buy an annual private jet license and it would be very expensive.

Maybe we do indeed need that tax. My only request would be the decision to be democratic and making sure the revenue doesn’t go to to the monopoly that injected people with plutonium. Instead it can be used to reverse the damage and with any excess being returned to their rightful earners.

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