How to save earth from hot earth theory and I don’t mean stop global warming.

Discussion in 'Earth Science' started by Christoph, Oct 31, 2018.

  1. geordief Valued Senior Member

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    1,010
    I didn't realize you were simply addressing the narrow point of oxygen depletion.

    As a chemical ignoramus I am nevertheless entirely convinced by billvon's interpretation and see it thankfully as a very minor issue (if an issue at all)
     
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  3. billvon Valued Senior Member

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    Right. But given that elderly people do not die (or get sick) en masse on aircraft trips - we have a LOT of margin. We could go from 20% to 18% (which we are at no risk of doing) and have it be no different than an airliner trip.
     
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  5. DaveC426913 Valued Senior Member

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    False equivalency.
    1] An airliner trip only lasts a few hours (nobody suggested the effects were felt within hours), and, more importantly:
    2] People who fly self-select for health. (i.e. if the lack of oxygen is pervasive, 24/7, you can't choose not to undergo the added stressor of low oxygen).

    An equivalent scenario is that, when air pollution rises for days at a time, the old, the young and the compromised do have a spike in complications and death.
     
    Last edited: Nov 3, 2018
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  7. billvon Valued Senior Member

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    MOST of the effects are felt early on; they get better after that. After the first day your body starts to acclimate.
    Of course. And some people walk around with oxygen tanks to deal with emphysema or COPD. That percentage might increase a bit.

    However, I would note that people aren't moving out of Denver due to health concerns. That's because our bodies adapt to different oxygen percentages.
     
  8. Quantum Quack Life's a tease... Valued Senior Member

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    20,101
    The margin is less than 1%.
    Keep in mind please that it is the ratio of gasses and not the pressure that is involved.
    So whilst the atmosphere becomes thinner with altitude the ratio of gasses tend to remain the same ( with exceptions of course)
    The ability to acquire oxygen due to lower pressures drops off, meaning that the "effective oxygen " percentage will decrease as altitude it gained.
    Note the distinction between "effective oxygen" and actual percentage of oxygen.

    "The important effect of this decrease in pressure is this: in a given volume of air, there are fewer molecules present. This is really just another way of saying that the pressure is lower (this is called Boyle's law). The percentage of those molecules that are oxygen is exactly the same: 21%. The problem is that there are fewer molecules of everything present, including oxygen.

    So although the percentage of oxygen in the atmosphere is the same, the thinner air means there is less oxygen to breathe."

    src: http://www.altitude.org/why_less_oxygen.php
    Logically any increase in CO2 or CH4 must mean that other gasses are offset.
    Simply put, as CO2, CH4, water vapor increases O2 must decrease as a proportion of atmospheric gasses. ( healthy humans need at least 20% O2 for proper function)
    ( have you noticed that breathing is easier in temperate climes than it is in tropical climes?)
    As previously claimed, there is only a safety margin of <1% before symptoms of Hypoxia become evident in the general population. For those who have compromised respiration ( ie smokers, elderly etc) those symptoms appear sooner, if not already.

    "We can not breath rain"
     
  9. Quantum Quack Life's a tease... Valued Senior Member

    Messages:
    20,101
    Changes in altitude effect only what is referred to as "effective oxygen" and not ambient gas percentages.
    Acclimatized persons have just as much risk of hypoxia as those at sea level.

    I believe it is no coincidence that the Anti smoking campaigns starting in the mid 80's ( quit) and scientific concern over climate change occurred at similar times.
    You will also note that in the West smoking bans in closed environments became law in many places. (CO of course mitigates Oxygen take up in humans.)

    Also just before the Scrips oxygen level program was started a few high altitude research labs >3500m had already detected a significant drop in high altitude O2 percentages. The alarming info was quickly removed from the web. ( so I can't give you a link except to say that it was published by the high altitude research station in the French Alps that apparently has dis-appeared off the web. ( a quick search fails to reveal it)

    I probably have screen prints on an old hard drive stored but really couldn't be bothered attempting to find them.
     
    Last edited: Nov 3, 2018
  10. billvon Valued Senior Member

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    15,783
    No. It is the partial pressure of oxygen that you care about. The ratio almost doesn't matter.

    At 35,000 feet, for example, you would quickly pass out without supplemental oxygen. (ppO2=.7psi.) However, on 100% oxygen you would be getting more oxygen that would would be getting at sea level (ppO2=3.6psi.) At sea level you get ppO2=2.9psi.

    The opposite is true as well. Saturation divers use hypoxic breathing gas mixtures because too high a ppO2 oxygen can kill you. For example, at 4 atmospheres (130 feet) a diver might use trimix 10/70 - meaning 10% oxygen, 70% helium and 20% nitrogen. And even though he is getting only 10% oxygen, he is getting twice the oxygen than a person at sea level gets breathing regular air.
    Right. That's ppO2.
    If you add CH4 to the atmosphere, and don't change anything else, the atmospheric pressure increases, and the ratio of oxygen to other gases goes down. But the ppO2 stays the same - so from your body's perspective, the same amount of oxygen is available.
    Yes. But again, all you care about is ppO2, not percentage.
    Since saturation divers breathe mixtures that contain far, far less than 20% oxygen - that is provably untrue. For example, a commercial dive to 900 feet might last several weeks, and the people there would breathe a mix of 2% oxygen and 98% helium (or similar.) Note that this results in ppO2 of 8psi, which is actually near the UPPER safe limit for oxygen. (i.e. they are at risk of getting too much oxygen even at 2%.)
    Yes. It's also harder to breathe after you have run a few miles. But neither has anything to do with gas mixes, or partial pressures of oxygen.
     
  11. Quantum Quack Life's a tease... Valued Senior Member

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    20,101
    I agree with most of what you have said however,
    Most if not all anthro CO2 production is achieved via the "burning" of O2. Effectively converting O2 to CO2

    For example an A320 Commercial liner will convert enormous amounts of O2 to CO2 thus replacing O2 with CO2.
    Last time I checked there were on average 8500 commercial jets in the sky at any given time. ( a few years ago)
    Commercial jet = oxygen to CO2 convertor
    Coal fired power stations = O2 to CO2 convertor
    Automobile ( non-electric) = O2 to CO2 convertor
    etc...
    So it could be easily stated that modern humans are replacing O2 with CO2 at ever increasing rates.

    The real question is about "How much by?"
    and how quickly we are eating up our 1% safety margin.

    Personally I do not trust the Scrips program due to it's "coincidental" establishment shortly after alarming reports ( French) were published and then abruptly removed, on the web many years ago.
    I tend to believe the Scrips program is contrived to provide a public front to inspire confidence while the "real" research is undertaken. ( quite understandable when you think on it)
    So as it stands the ambient O2 percentages are not readily available and that in itself is something of concern.
     
    Last edited: Nov 4, 2018
  12. Quantum Quack Life's a tease... Valued Senior Member

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    20,101
    I guess the point that I am attempting to make is that it is not just the greenhouse effect caused by CO2 we need to worry about, it is also the fact that we are replacing O2 with CO2 ( and other gasses) infringing on our safety margin of a mere 1%
    Hyperthermia is no way as scary as Hypoxia (suffocation) IMO
    But combine the two and we have a really bad night mare situation evolving as we speak.
     
    Last edited: Nov 4, 2018
  13. Quantum Quack Life's a tease... Valued Senior Member

    Messages:
    20,101
    Just as a matter of interest:
    A320 commercial jet
    • Cruising speed = 853 km/h
    • Fuel consumption = 3025 L/h
    • Passenger capacity = 150 (max)
    • Fuel consumption per km = 3025 ÷ 853 = 3.546 L/km
    Thus, CO2 emission rate = 3.546 x 2.580 = 9.149 kg/km
    src: https://micpohling.wordpress.com/2007/05/08/math-how-much-co2-released-by-aeroplane/
    credibility: Unknown

    Assume all large jets to be similar
    multiply by 8500...
    that's a lot of Oxygen being converted to CO2
    Assume an Air/ fuel ratio of say 14:1
    reduce to O2 component of ambient air say (20%)
    14/5 = 2.8
    gives you an oxygen to fuel ratio of 2.8 : 1



    then add all the non-electric automobiles, coal fired power stations etc. conversion of oxygen to CO2 and you get the picture...
     
    Last edited: Nov 4, 2018
  14. billvon Valued Senior Member

    Messages:
    15,783
    Agreed. However, keep in mind that we are changing CO2 concentrations in parts per million. So going from 280ppm to 400ppm (what we have done so far) means a change of .028% to .04%. If we reduce O2 concentrations by the same amount (which we don't, but bear with me here) then we reduce O2 concentrations from 20.950% to 20.942% - the equivalent of going up in altitude about 50 feet.

    So if you can breathe at the top of your office building you will be OK.

    However, burning things does not significantly change the amount of oxygen in our atmosphere. Why? Because oxygen in our air comes from photosynthesis, and photosynthesis creates oxygen by splitting water molecules. And more CO2 helps photosynthesis proceed faster. So more CO2 = more photosynthesis = more oxygen. The source of that oxygen is water, and we have plenty of that.

    So why doesn't O2 keep rising out of control, if plants keep making more and more of it? Because the rate of natural fire is almost directly dependent on O2 concentration. Raise O2 concentrations to 25% and wildfires would get hotter, burn more and burn deeper. Raise it above that and you get to the point where even dirt will burn. That keeps O2 levels in check.

    Yep. And plants are converting H20 to O2 at ever increasing rates.

    30 seconds of Googling revealed a dozen studies over O2 concentration. Here's one:
    ================================
    Earth's Atmospheric Oxygen Levels Continue Long Slide
    By Charles Q. Choi, Live Science Contributor | September 22, 2016 02:01pm ET

    Atmospheric oxygen levels have declined over the past 1 million years, although not nearly enough to trigger any major problems for life on Earth, a new study finds.

    The research behind this new finding could help shed light on what controls atmospheric oxygen levels over long spans of time, the researchers said.

    Atmospheric oxygen levels are fundamentally linked to the evolution of life on Earth, as well as changes in geochemical cycles related to climate variations. As such, scientists have long sought to reconstruct how atmospheric oxygen levels fluctuated in the past, and what might control these shifts.

    The new estimates suggest that atmospheric oxygen levels have fallen by 0.7 percent over the past 800,000 years. The scientists concluded that oxygen sinks — processes that removed oxygen from the air — were about 1.7 percent larger than oxygen sources during this time.

    Although a drop in atmospheric oxygen levels might sound alarming, the decrease the researchers found "is trivial in regard to ecosystems," Stolper told Live Science. "To put it in perspective, the pressure in the atmosphere declines with elevation. A 0.7 percent decline in the atmospheric pressure of oxygen occurs at about 100 meters (330 feet) above sea level — that is, about the 30th floor of a tall building."
    ====================================
     
  15. Quantum Quack Life's a tease... Valued Senior Member

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    20,101
    Perhaps I am mixed up in my thoughts but it seems to me that you are still mixing pressure of oxygen with percentage of oxygen relative to other gasses.
    Are you?
    Self testing:
    Percentage of O2 is not relative to pressure or altitude. Assuming even-dispersal. Even in the Thermosphere (> 330 kms) the ratio of O2 to other gasses remains the same.
    Say Karman line at 100kms, O2 would still be the same percentage (ratio)
    Am I correct?
     
  16. iceaura Valued Senior Member

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    28,943
    Edit out - too quick. Arithmetic done.
     
  17. geordief Valued Senior Member

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    1,010
    Thankfully so.It would be very bad news if this was a concern over and above carbon related global warming.
     
  18. iceaura Valued Senior Member

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    28,943
    I keep editing late on you. Sorry again.
     
  19. Quantum Quack Life's a tease... Valued Senior Member

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    20,101
    There seems to be some confusion about the difference between "effective" O2 level and actual O2 level. See post #45 and maybe google Boyles law if necessary.
    until that is sorted out any further discussion about the ratio of O2 consumption to Co2 production would be futile.
     
  20. iceaura Valued Senior Member

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    28,943
    Billvon did the central arithmetic - I posted too quickly with a lesser point.
    My point was simply that this:
    overlooks not only the fact that our safety margin is much larger than 1%, but the fact that CO2 is such a small fraction of the air that even very large percentage increases in it would have little effect on O2 concentration.

    If you are going to worry about O2 concentrations, worry about the effect of AGW on photosynthesis - net primary productivity - in the world's oceans.
     
  21. billvon Valued Senior Member

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    15,783
    Right. We have a relatively well mixed atmosphere.
    Things start to change in the thermosphere. First off you don't have O2 - you have O (atomic hydrogen) due to dissociation by UV. You also have a lot more helium, and at those altitudes, gases start to stratify by weight (i.e. it's not well mixed any more.) But pressures are so low that it's not really a gas any more - it's a bunch of atoms and molecules going in pretty much straight lines.
     
  22. Quantum Quack Life's a tease... Valued Senior Member

    Messages:
    20,101
    The issue I am postulating I feel is way too complex to describe adequately as I lack the qualifications needed.
    However as a auto technician years ago ( they called us guys motor mechanics in those days) the ratio of O2 to fuel was closer to 4:1 and certainly not 1:1
    so... it is relatively easy to extend and suggest that for every CO2 unit produced ( in the mix of gasses produced) a significant amount of O2 must be consumed. ( potentially at a rate of 4:1)
    Even so, on face value, that means that a relatively trivial amount of O2 has been consumed in the production of our current atmospheric CO2.
    This "face value" is misleading.
    This does not account for the CO2 that is being taken up by oceans and increased CO2 fertilization effects.
    One can assume that any increase fertilization effects become net gain zero as the flora involved have to sustain their own existence with the O2 and CO2 they produce.
    There fore it can be assumed that the Anthro CO2 production is significantly greater than that which is retained in the atmosphere.
    Quantifying that CO2 produced and absorbed is not easy, ocean acidification ( accounts for 30-40% of anthro production), dead zones ( 405 at last count - 2008)

    Summary:

    Anthro CO2 production is significantly higher than the .04% indicated in the atmosphere. Which means that O2 consumption is considerably higher than that which is indicated by only atmospheric data.
    =====
    It is worth noting that the confusion between "effective O2 " and actual O2 is often demonstrated in many supposedly erudite reports when dealing with this issue indicating a degree of incompetence or deliberate obfuscation.
    Switching "category" or context to reduce alarm is one possibility.

    Also prior to the Scrips O2 program being established scientific reports from well regarded high altitude research stations ( French and Swiss) of ambient O2 being as low as 19.7% were published on the net and then rapidly removed from the web at the time indicating some sort of intervention ( or cover up) Perhaps they found their reports mistaken and removed them to prevent embarrassment. I shall never know.
    It does mean however that the currently accepted value of 20.942% may be wrong.
    With reports of 19.7% ( say 12 years ago) and a safety margin of only 1% and what appears to be a increase in respiratory/heart disease in the wider community (West) even with significant reduction in smoking due to successful Quit campaigns one could easily go down a conspiracy theory rabbit hole.
    Also opioid use has sky rocketed and one aspect of opioid use is for the dampening anxiety induced breathing problems ( hyperventilation)

    So to me, ( just so you know where I am coming from) when you look at the big picture you see a global population, especially in the West ( data availability), that is starting to experience increased breathing problems which forces me to the tentative conclusion that atmospheric O2 depletion causing mild hypoxemia may be, in part, responsible.

    Suffice to say that we Humans are incredibly sensitive and thus responsive to "actual" O2 levels.
     
    Last edited: Nov 4, 2018
  23. Quantum Quack Life's a tease... Valued Senior Member

    Messages:
    20,101
    thanks for that.... perhaps I was over generalizing...
     

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