or, "I am acutely aware of Hypercapnia and issues surrounding it and breathing CO2 is a real no no"
whether in an auditorium, at Boulder or at base camp Everest
whether in an auditorium, at Boulder or at base camp Everest
Climate-gate
- Thread starter Photizo
- Start date
From your refusal to answer I will take it you haven't.
I have. I've been to 26,000 feet pretty regularly where there actually isn't enough ppO2 to breathe, and hypoxia comes on rapidly and obviously at those altitudes without supplemental O2. I've spent quite some time in Boulder and Loveland Pass. And those places, although much lower in oxygen content than sea level, don't make you feel sick or uncomfortable. Your body is quite good at compensating for such changes.
Exceptions are heavy activity (mountain biking or skiing) or, at altitudes above about 10,000 feet, sleeping. When you sleep something interesting happens. Your body's respiratory drive is driven primarily by CO2 concentration, not oxygen concentration; that's secondary. So you naturally breathe more deeply when you sleep and you get enough oxygen. But that also flushes CO2 more effectively, and thus your body loses its respiratory drive temporarily. You stop breathing (your body says you don't need to) until your backup oxygen sensors in your carotid arteries send a warning, and you breathe very deeply for a few seconds to get things back on track. This is called Cheyne Stokes breathing.
But again, all this is happening at ppO2 levels far, far below anything you will encounter at sea level (or as a result of combustion.)
but as you stated earlier the percentage of oxygen/air does not reduce with altitude.
However in a crowded auditorium at sea level it does.
Maybe place that virtual auditorium at Boulder. Fill it with people and see what happens...
Right. The RATIO of oxygen to nitrogen does not change. The TOTAL AMOUNT of oxygen available to you changes.
Same thing that happens at sea level. Why? Because CO2, not O2, is what is causing the problem.
Sleeping is an interesting issue.. sleep apnea as distinct to Cheyne Stokes is quite common.
so the body will continue to produce the same CO2 regardless of O2 levels ( if activity remains same )
Thus building internal CO2 in an oxygen depleted environment.
Thus building CO2 in an environment that still has plenty of oxygen, as the Boulder example demonstrates.
So why do you need to use supplemental oxygen at 26000 feet?
Say you are a guy who always historically starts to use Sup OX at a particular land mark at 25600ft. Every year you visit the same spot and then one year you realize you need Sup Ox at 25000n feet instead of 25600 feet. The next year it is 24500ft...
If you ignore age related and other conditions beyond Oxygen levels what would you put the change down to?
*Please feel free to replace the altitudes in the example with more appropriate numbers...
If you ignore age related and other conditions beyond Oxygen levels what would you put the change down to?
*Please feel free to replace the altitudes in the example with more appropriate numbers...
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Because the partial pressure of oxygen has declined past the point that your body can adapt to the decrease.
So the question you just asked is "if the only possible answer is oxygen levels then what causes the change?" The answer to that question is oxygen levels.
However, if presented with that issue in a more realistic situation, the first thing I would do is measure the ppO2 at those altitudes. If they don't show much change, then something else is the culprit (like changing weather patterns.)
but not ambient CO2 levels yes?
Measuring ppO2 is apparently not easy... the human body is a great measuring device in this regard...by using levels of hypercapnia (blood CO2) we can gather an approximation of O2 levels perhaps
As an aside, can I ask how often you get to those sorts of altitudes... I personally have never been any where near that high.. I am lucky to survive at sea level... [chuckle]
We don't really have mountains per see here in Australia...
We don't really have mountains per see here in Australia...
Again, you asked ""if the only possible answer is oxygen levels then what causes the change?" then the answer is oxygen levels. Had you asked "if the only possible answer is CO2 levels then what causes the change?" the answer would be CO2 levels.
?? It is trivial. Every car on the road has an accurate oxygen sensor in its exhaust system, and every smog measurement device has one as well. They are common in rebreather SCUBA systems as well. It's a simple measurement, one that has been made countless times.
Well, no - as I mentioned before they are often out of whack.
Used to be 10-20 times a year, now a lot more infrequent. Highest I've been is 30,000 feet, where you need full time 100% oxygen (not just supplemental.) All were from skydiving, which means you have no time to adapt to the change.
I am going to quote an academic and wonder what your or others thoughts would be:
"Evidence from prehistoric times indicates that the oxygen content of pristine nature was above the 21% of total volume that it is today. It has decreased in recent times due mainly to the burning of coal in the middle of the last century. Currently the oxygen content of the Earth’s atmosphere dips to 19% over impacted areas, and it is down to 12 to 17% over the major cities. At these levels it is difficult for people to get sufficient oxygen to maintain bodily health: it takes a proper intake of oxygen to keep body cells and organs, and the entire immune system, functioning at full efficiency. At the levels we have reached today cancers and other degenerative diseases are likely to develop. And at 6 to 7% life can no longer be sustained. " [2013]
and another author (*?)
"It is becoming clear that getting rid of CO2 is not enough; oxygen has its own dynamic and the rapid decline in atmospheric O2 must also be addressed. Although there is much more O2 than CO2 in the atmosphere - 20.95 percent or 209 460 ppm of O2 compared with around 380 ppm of CO2 – humans, all mammals, birds, frogs, butterfly, bees, and other air-breathing life-forms depend on this high level of oxygen for their well being [5] Living with Oxygen (SiS 43). In humans, failure of oxygen energy metabolism is the single most important risk factor for chronic diseases including cancer and death. ‘Oxygen deficiency’ is currently set at 19.5 percent in enclosed spaces for health and safety [6], below that, fainting and death may result." [2009]
an article worth reading on O2 depletion:
http://www.i-sis.org.uk/O2DroppingFasterThanCO2Rising.php (2009)
"Evidence from prehistoric times indicates that the oxygen content of pristine nature was above the 21% of total volume that it is today. It has decreased in recent times due mainly to the burning of coal in the middle of the last century. Currently the oxygen content of the Earth’s atmosphere dips to 19% over impacted areas, and it is down to 12 to 17% over the major cities. At these levels it is difficult for people to get sufficient oxygen to maintain bodily health: it takes a proper intake of oxygen to keep body cells and organs, and the entire immune system, functioning at full efficiency. At the levels we have reached today cancers and other degenerative diseases are likely to develop. And at 6 to 7% life can no longer be sustained. " [2013]
and another author (*?)
"It is becoming clear that getting rid of CO2 is not enough; oxygen has its own dynamic and the rapid decline in atmospheric O2 must also be addressed. Although there is much more O2 than CO2 in the atmosphere - 20.95 percent or 209 460 ppm of O2 compared with around 380 ppm of CO2 – humans, all mammals, birds, frogs, butterfly, bees, and other air-breathing life-forms depend on this high level of oxygen for their well being [5] Living with Oxygen (SiS 43). In humans, failure of oxygen energy metabolism is the single most important risk factor for chronic diseases including cancer and death. ‘Oxygen deficiency’ is currently set at 19.5 percent in enclosed spaces for health and safety [6], below that, fainting and death may result." [2009]
an article worth reading on O2 depletion:
http://www.i-sis.org.uk/O2DroppingFasterThanCO2Rising.php (2009)
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By weight oxygen is 23% of the air, or by molecule fraction 20%. I.e. in terms of molecules, the O2 concentration is 200,000ppm.http://www.hse.gov.uk/carboncapture/carbondioxide.htm said:
The CO2 rarely is as high as 400ppm but to be conservative, lets assume that and ask: How much would the O2 concentration drop to double the CO2 concentration to 800ppm, by greater burning of fossil fuels? Answer is 400ppm or the O2 concentration would fall to: 199,600ppm.
Likewise an increase in the CO2 by 4600ppm will bring the total to the long term dangerous level: 5,000ppm. If done by more burning of fossil fuels, the O2 concentration would fall from 200,000 to 195,400ppm. A drop of 4600 / 200,000 or in percent, of 46 /20 = 2.3% I. e. Many humans breath air with five times greater reduction in O2 pressure with little ill effect, but not with the CO2 permanently at 5,000ppm.
How high a hill would you need to live on to have the O2 reduced by 2.3%? Answer is easily found with calculator here: http://www.altitude.org/air_pressure.php but pressure change is given only in one percent steps. At 315 meters there is only 96% of sea level pressure and at 225m there is 97% thus at 200m the O2 pressure has also fallen by 2.3%. Sao Paulo is three times that height above sea level so that 2.3% O2 reduction is no problem unless it was caused by great increase in burning fossil fuel, then the CO2 produced would be lethal for many and shorten the lives of all very significantly.
SUMMARY: Billvon is correct and QQ is posting more nonsense. Oxygen depletion by burning fossil fuels is no problem, would not even be noticed, but the CO2 produced would kill many, if not most.
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So you dispute the article I linked to?
No, but they don't say O2 depletion by burning fossil fuels is of any significance compared to the lethal effects of the CO2 produced. I.e. they ignore the real problem.
Do you dispute the computations or conclusion of post 1875%? If so, what is the error?
Iam on mobile so my response will have to wait.
That is, simply put, complete bullshit.
So people in Denver are all either fainting or dead? Pretty funny!
Good article from the Science and Public Policy Institute, discussing the article you linked:
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Is there someone at The Guardian who has some common sense left? Could you please stop printing insane people like Peter Tatchell who help to transform your daily into an expensive and dirty piece of toilet paper?
Professor Wallace Broecker of Columbia University has written: “An oft-heard warning with regard to our planet’s future is that by cutting back tropical forests we put our supply of oxygen gas at risk. Many good reasons exist for placing deforestation near the top of our list of environmental sins, but fortunately the fate of the Earth’s O2 supply does not hang in the balance. Simply put, our atmosphere is endowed with such an enormous reserve of this gas that even if we were to burn all our fossil fuel reserves, all our trees, and all the organic matter stored in soils, we would use up only a few percent of the available O2. No matter how foolishly we treat our environmental heritage, we simply don’t have the capacity to put more than a small dent in our O2 supply. Furthermore, the Earth’s forests do not play a dominant role in maintaining O2 reserves, because they consume just as much of this gas as they produce. In the tropics, ants, termites, bacteria, and fungi eat nearly the entire photosynthetic O2 product. Only a tiny fraction of the organic matter they produce accumulates in swamps and soils or is carried down the rivers for burial on the sea floor."
While no danger exists that our O2 reserve will be depleted, nevertheless the O2 content of our atmosphere is slowly declining–so slowly that a sufficiently accurate technique to measure this change wasn’t developed until the late 1980s. Ralph Keeling, its developer, showed that between 1989 and 1994 the O2 content of the atmosphere decreased at an average annual rate of 2 parts per million. Considering that the atmosphere contains 210,000 parts per million, one can see why this measurement proved so difficult. This drop was not unexpected, for the combustion of fossil fuels destroys O2. For each 100 atoms of fossil-fuel carbon burned, about 140 molecules of O2 are consumed.
The surprise came when Keeling’s measurements showed that the rate of decline of O2 was only about two-thirds of that attributable to fossil-fuel combustion during this period. Only one explanation can be given for this observation: Losses of biomass through deforestation must have been outweighed by a fattening of biomass elsewhere, termed global “greening” by geochemists. Although the details as to just how and where remain obscure, the buildup of extra CO2 in our atmosphere and of extra fixed nitrogen in our soils probably allows plants to grow a bit faster than before, leading to a greater storage of carbon in tree wood and soil humus. For each atom of extra carbon stored in this way, roughly one molecule of extra oxygen accumulates in the atmosphere.
Finally, here is what Dr. Ray Langenfelds from CSIRO Atmospheric Research, Australia, has to say about the graph of the decline in atmospheric O2 at Cape Grim: “The changes we are measuring represent just a tiny fraction of the total amount of oxygen in our air - 20.95 percent by volume. The oxygen reduction is just 0.03 percent in the past 20 years and has no impact on our breathing. Typical oxygen fluctuations indoors or in city air would be far greater than this.”
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