How much do rockets pollute?
everydayastronaut.com
everydayastronaut.com
I supported the Ozone Hole studies in the mid 80's, and we found CFCs destroyed a protective part of our atmosphere. That recovered over time, but there are some rogue manufacturers using CFCs again, and leaking massive quantities.
We know airborne nuclei like soot cause localized precipitation, so that does change weather (it's called cloud seeding.)
We really need to know more about the effect of rockets at high altitudes, and airliner jet engines at 30,000'.
I have a strong feeling airliners have a significant effect due to the volume of air traffic and how dirty burning jet fuel is.
To see how jet engines could have a significant effect, there are around 10,000 airliners worldwide, which are in the air more than 12 hours each per day typically.
The break in air travel due do corona virus is an excellent time to compare atmospheric samples before and after the pause.
Somehow the climate activists have decided to make a lot of noise about flying but it's mostly unfounded. They go as far as using very old models of planes in their calculations (e.g. a 737-400 model) and claiming that's the amount of CO2 per passenger of all air travel. While that model is out of use by the airline for at least 15 years already. It was designed in 1985.
So beware of the data and tricks like this when you're told flying is so bad for the environment.
The reason flying represented only 2.5% of global emissions is because most people never do it. There's a small subset of people, mainly in the West, who do the vast majority of flying.
As this BBC article makes clear, a return flight from London to San Francisco represents half the emissions of the average London resident. If you fly a couple of return long haul trips a year, they'll emit the same as everything else you do for the rest of the year.
https://www.bbc.com/future/article/20200218-climate-change-h...
Looking at old aircraft will make the figures seem worse, but it's not like new aircraft are an order of magnitude more efficient.
The best case budget airlines (high seat density and high seat utilisation) today get about 2.27L/100km for each seat. The 737-300 was about 3.46L/100km - so about 65% of what it used to be. Better for sure, but not "we've fixed the problem" better. I'm not sure to what extent those figures take into account changing seat density and utilisation.
A far more common round trip London to Paris flight is ~6 gallons of fuel. So, someone doing that every weekend is still using 38% less fuel per year is using our 15,000 mile driver.
Flying only emits 2.5% of global CO2 because it’s surprisingly efficient and most people don’t travel ultra long distances frequently. LA to London takes a ~10 hour travel day each way making it unappealing to do frequently.
Your argument is also entirely generic. There is nothing that isn’t “irrelevant in comparison to industry and electrical generation”. Of note, “industry” can be split into arbitrary parts that would all fail your standard of significance. Meat production produces “only a fraction of CO2”. Residential heating, likewise, “produces a fraction of CO2”, and so do lighting, consumer goods, or the entire shipping industry.
Following your logic, nothing really matters, nor can anything be done.
What part of high altitude is unclear to you?
It’s an activity that’s visible to everyone, it’s a personal choice (in the way that power generation usually isn’t), and a lot of air travel is a luxury and a convenience (again, more so than electricity).
Is it practical to track down the culprits? I presume it would mean prison time.
but how was the hydrogen in the fuel cell produced in the first place? i guess it’s an energy consuming process that produces a decent level of pollution, whether it’s by electrolysis, heating of a chemical in the presence of a catalyst, etc.
CO + H2O ⇌ CO2 + H2
For every tonne of hydrogen produced this way, 9 tonnes of CO2 is also produced.
Also, isnt this a non-issue, because (at least in theory) the reaction is contained in your converter plant, where you can collect the CO2?
What're you going to do with that collected CO2 other than releasing it to the atmosphere?
Hydrocarbons pollute by their very nature. In order to have a carbon neutral hydrocarbon cycle you need an impractical number of CO2 capture facilities.
There’s no way this can be correct.
You can’t use hydrogen to produce the electricity used in hydrogen electrolysis, because that’s not permitted in this universe.[1]
Therefore the electricity has to come from some other source, which all generate life-cycle carbon emissions.[2]
1. https://en.wikipedia.org/wiki/Second_law_of_thermodynamics
2. https://en.wikipedia.org/wiki/Life-cycle_greenhouse-gas_emis...
Also, that tidal power looks pretty good...
your point highlights my initial point about hydrogen fuel - ie we must look all the way up the chain and account for all polluting steps, instead of simply focusing on a single aspect.
Here’s the Wikipedia entry on the subject: life-cycle greenhouse gas emissions - https://en.wikipedia.org/wiki/Life-cycle_greenhouse-gas_emis...
Before he does it on Mars he'll have to perfect it on Earth first. I hope he does more than that and starts using carbon neutral methane for all his Starship flights on Earth.
> Although all rocket engines do run fuel rich for the right balance of heat management and performance, so there is likely going to be unburnt fuel expelled regardless of the cycle type, but much more when it is an open cycle engine.