Not flying those rockets will have no effect. A single launch puts out about as much CO2 as a single full transatlantic flight. Consider how many of those fly every single day, let alone the shorter flights.
Setting aside other pollutants in rocket soot (of which there are many) and only looking at CO2:
Which rocket are you saying produces that much CO2, and where did you get that convenient number? Falcon 9 weighs like half a million kg. Falcon Heavy is about three times that. Starship will weigh like 5 million kg. I hope you're not under the impression that all rockets uniformly produce the same emissions. It depends on a few different factors.
Falcon 9 burns RP-1 kerosene, and uses twice as much of that fuel as Soyuz.
Falcon Heavy burns 440 tons of RP-1 kerosene. A 747-8i can carry 60,755 gallons of jet fuel (similar distillate), weighing 407 thousand lbs, or 203 tons. Its range at maximum take-off weight is 9,210mi. A flight from Boston to Glasgow is about 3k miles, so that's three transatlantic flights per tank, or 6.5 transatlantic flights per Falcon Heavy flight.
I wonder if Mr. Musk would support forcing spaceflight companies to offset their carbon emissions by paying for reforestation. Somehow, I doubt it.
Furthermore, rocket emissions deliver gases directly to the middle and upper atmosphere, so their pollution is more impactful pound-for-pound than aircraft emissions.
And in fact, Mr. Musk wants to replace air travel with rocket travel. Check out this SpaceX video from 2017. It's not just one or two flights we're talking about. He wants to fly thousands. https://www.youtube.com/watch?v=zqE-ultsWt0
These are all fair points and I'm going just off quick Googling. But here's what I found regarding the Falcon 9 [1][2] which puts it around 425 Metric Tons per flight. And for a fully loaded airliner there are CO2 emission numbers per seat which can put it up in the 500 Metric Ton range [3] for a long flight. Our numbers are not that far apart. 3 flights vs 1 flight is a rounding error in the scale of global CO2 emissions.
The Starship numbers are much harder to analyze though, it entirely depends on how you get the methane, because yes, it will put out a LOT more CO2 per flight. Methane can be collected from the production of coal/natural gas/oil where it is burned anyway, or as SpaceX has said they would like to do, from the Sabatier process which would actually be carbon neutral given that you can produce Methane by extracting CO2 from the atmosphere.
I can't deny that it will spread the CO2 further through the atmosphere even if it is carbon neutral, but when it comes down to it, rocket launches are now and for the foreseeable future a minuscule portion of CO2 output and airplanes, cars, and industry are all orders of magnitude greater emitters.
And then when it comes to Musk, it just seems weird to say he isn't doing enough to combat CO2 on a post about him donating $100M to help improve CO2 removal and also ignore what electrification of cars can and already has done for CO2 emission reduction.
I think my math is fairly reasonable for a back-of-the-envelope calculation and I also note that we both acknowledge that we're within an order of magnitude of one another. However, we have pretty accurate information about airliner fuel consumption, and one transatlantic flight is just not the same as a single Falcon flight. That's a fact.
> And then when it comes to Musk, it just seems weird to say he isn't doing enough to combat CO2 on a post about him donating $100M to help improve CO2 removal and also ignore what electrification of cars can and already has done for CO2 emission reduction.
Forget Mr. Musk for a second. If Philip Morris reports 7.5B of revenue alongside a widely publicized anti-smoking campaign, are you going to give them a pat on the back or are you going to say that good PR can be an intentional distraction from the tangible externalities of profit-seeking activity?
Now, back to Mr. Musk, a man who runs one business whose profit depends entirely on government market controls, and another business that depends largely on government contracts. When Trump was president, Mr. Musk decried COVID lockdowns as un-Constitutional. However, now Biden is president and Mr. Musk is pushing a few dollars (relative to his vast fortune) toward a green initiative.
In that context, and given the fact that petroleum-powered flight on the scale publicly suggested by Mr. Musk's future plans would definitely produce a nontrivial amount of pollution, we shouldn't be so quick to herald Mr. Musk as some kind of druidic entrepreneur who loves Earth so much that he wants to make a second one on Mars.
Someone else accused me of having strife with my family rather than interpreting my comments as a good-faith dissent from widespread adulation of Mr. Musk's ostensible benevolence. I don't think that would have happened if I had expressed skepticism about Big Tobacco instead of Big Rocket.
EDIT: Methane from Starship is particularly problematic because, if leaked, it is so much more damaging to the atmosphere than CO2. This is part of the reason that venting natural gas from wells unequipped to capture it is a huge no-no. I agree that evaluating emissions from Starship is a bit more challenging.
