What a Blunder That Would Be

Okay, currently CO2 is at about 400 ppm. Oxygen is around 20.95%. Creating of one CO2 molecule uses up one O2 molecule.

Disregarding photosynthesis (using CO2 and producing O2), let's assume we burn enough to quadruple CO2 levels from 400 ppm to 1600ppm. 100ppm = 0.01% So grossly oversimplifying, that means O2 levels would be at 20.83%.

Don't worry to much about depleting O2 levels.

CO2 is a very small fraction of the oxide products .

Don't be careless in your assumtions.

'CO2 is a very small fraction of the oxide products'

... perhaps you could provide something a little less vague than 'very small fraction'.

I think that is.a safe assumption that when typically burning fossil fuels a large portion of the O2 consumed will be end up as CO2. Any portion that ends up as H2O, CO or NOx or SO2 would easily be covered by the extremely generous assumption that we base calculations on quadruple current CO2 and ignore photosynthesis, which still only yields a very minor change. Even if CO2 were only 1/6 of the O2 consumption, doubling current CO2 levels with no photosynthesis would only bring O2 level to 20.71%....that is a grossly simplified with factors heavily leaning towards worst case.

You have suggested that assumption is careless. Please set me straight if I have made some glaring error, I appreciate gaining better perspective.

TINIAC;

Your well-studied comments are always appreciated. It is perhaps I jumping to conclusions here. But please be patient with me.

When we consider only O2 consumption through fossil fuel combustion and ignore the myriad of other natural and man-made chemical processes that consume it; are we ignoring a significant percentage of that consumption? An example; is the natural process of weathering a more significant consumer than fossil fuel combustion?

How is it possible to consider trending concentrations of atmospheric oxygen without first considering the ocean solute?

Is it not "probable" that O2 was "stored" as ocean solute when atmospheric O2 levels were much higher than today? And that appreciable reductions in atmospheric concentration would first require that this "stored" oxygen in the ocean come out of solution?

I believe it is accepted science that O2 consumption through all processes far exceeds that produced through photosynthesis; there must be significant sources that assist in maintaining O2 concentrations in the atmosphere. The most obvious would be "stored" O2 coming out of ocean solution.

Your knowledge is highly respected and appreciated. Please take a few more minutes to share a little more.

As a side note: I found it interesting to learn that the O2 released during photosynthesis comes from H2O and not CO2. That the consumed CO2 was used in the production of sugars. This being determined through isotopic analysis using O18 as the tracer. The tracer was found in the sugars but not the released O2.

Any links for:

I believe it is accepted science that O2 consumption through all processes far exceeds that produced through photosynthesis;

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Here is a start. The fact that the partial pressure of O2 is decreasing is clear indication that Photosynthesis is not keeping up with consumption. AND this decrease is occurring even with the O2 coming out of ocean solution. See - Henry's Law.

http://scrippso2.ucsd.edu/

I've got a lot on the schedule at work today, so I don't have time fo follow links, so I'll just go with straight Logical Axioms:

IF O2 is decreasing because production is not keeping up with consumption

AND current efforts at 'reducing global warming' are focusing on reducing CO2 production.

AND CO2 production is one of the largest 'consumers' of O2

THEN continuing our efforts to 'reduce CO2' will reduce consumption of O2, which is what we need to do to bring O2 production and O2 consumption back into balance.

So, looking logically, 'O2 consumption' does not need to be considered as a 'separate issue' to 'CO2 reduction' at this time. If we manage to reduce CO2 levels to pre-industrial revolution levels and we're STILL losing O2, then we'll have proof that it's a separate problem, but until then, diverting resources in that direction will only slow down the efforts to reduce CO2.

If I have made any errors in my logic, please let me know.

This would make this an instrument to promote CO2 reduction schemes.

Please note this will exclude sequestration from the list as feasible options.

I still wonder if we could just promote energy usage reduction schemes starting with switch off what you do not need.

Ok! Switching off now!

Nice idea, but it seldom if ever works. How many times have you seen someone "supersize" a meal, and justify it with a diet soft drink? Or leave a new LED lamp on because it draws the same as two incandescent night lights. I'm always amazed that we seem to look at new technologies and seldom mention the downsides. The automobile replaced the horse, which had made cities unbearable in the summer. Anyone else remember the phrase "electricity too cheap to meter"? Does anyone know the downside to fusion reactors? While technology solves the immediate problem, it sometimes leaves us with a greater future problem. And to this I have no answer, I really like coming home to 6000 lumens of light in the drive provided by 70 watts of LED fixtures.

I don't have a feel for the magnitudeof O2 contributed by upwelling waters could be. There are so many factors. The transit times are on the order of millenia for some....which is a long for us, but not so long with respect to sizeable changes in O2 concentrations.....which suggests it should not be that significant.

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Interesting that the O2 produced can be traced to the water, but I don't think it is reasonable to say it does not come from CO2.

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6CO2 + 6H2O + light ---> C6H12O6 + 6O2

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Notice that only 6 oxygen atoms are contributed by the water, yet 12 oxygen atoms comprise the 6 oxygen molecules. At most, 1/2 the oxygen comes from water and at least 1/2 comes from the CO2.

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In all fairness there are lots of holes in the idea of trying to box in O2 reduction using CO2 concentrations. For looking at burning hydrocarbons it is useful to get an goss idea of scope...so general that the whole don't matter. But no restricted to just burning hydrocarbons it isn't useful.

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I thought you were implying that human use of fossil fuel might be depleting sufficient O2 to be a concern. I think even if we go through the numbers for projections of hydrocarbons to be burnt this century, I don't think the change in O2 concentrations will be that great.

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If you are suggesting that nonanthropogenic processes might be depleting O2 in a way that is difficult to currently measure, my feeling is that we should not do anything about that currently as the law of unintended consequences would appear the large threat IMHO.

Wow. I wrote that late last night, and it shows!

"I don't have a feel for the magnitude of O2 contributed by upwelling waters could be. There are so many factors. The transit times are on the order of millennia for some....which is a long for us, but not so long with respect to sizeable changes in O2 concentrations.....which suggests it should not be that significant."

Are we ignoring Diffusion? Wouldn't Fick's Law apply here? If so how would convective transport (upwelling) compare to diffusion transport?

" -----I don't think the change in O2 concentrations will be that great."

When you say " will (not) be that great" what kind of numbers are you talking? Remember that most of the O2 used industrially is also taken from our atmosphere. If you took the total atmospheric oxygen and subtracted industrial and energy oxygen consumption wouldn't that approximate the atmospheric O2 deficit from the dynamic equilibrium prior to the Anthropocene? This ignoring anthropogenic impact on photosynthesis and bio-respiration.

It would seem reasonable that the chemical states of our planet's oceans and atmosphere were in some type of dynamic equilibrium prior to human industrialization. It would not seem too difficult to roughly calculate that O2 deficit.

"Interesting that the O2 produced can be traced to the water, but I don't think it is reasonable to say it does not come from CO2."

I found this very interesting - http://www.howplantswork.com/2009/02/16/plants-dont-convert-co2-into-o2/ - please comment if you see error.

Okay, first foe the photosynthesis.

6H2O + 6CO2 + light --> 6O2 + C6H12O6

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What the link you provided say is that when plants were fed with 18O water that the 18O was found in the O2 produced but not in the C6H12O6 produced.

Contrary to the claim made in the title of the link that does not demonstrate that oxygen produced does not come from CO2, only that oxygen from the H2O contributes to the O2 produced.

That page has failed to show a balanced equation....if they had, the error would be apparent.

As I noted in the post to which you responded, the balanced equation shows that there is insuffici3nt oxygen available in just the H2. Thus, 'at most 1/2 of the oxygen comes from H2O and at least 1/2 of the oxygen comes from CO2'.

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Basically the conclusion drawn by the web page linked is incorrect.

Fick's law does not fit well enough to be of much use here. O2 solubility in seawater changes significantly with temperature/salinity/pressure. Coupled with the very significant mass flow aspects this renders Fick's law woefully insufficient for useful predictions.

Just look up typical dissolved oxygen concentrations with sea depth. At the surface, levels tend to be highest, dropping off rapidly for several hundred meters then gradually climb again even deeper.

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Sure there is exchange of oxygen with the sea, both ways. The thing is, even if the oceans were just a static pool of homogenous solubility, diffusion would not mask a change since it must be driven by a difference.....small difference, small effect.

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The information I can find on historic atmospheric oxygen concentrations details an increase of several percent over the past 20 million years. With deep sea transit times of only 1000 years, it would appear that any upwelling waters likely experienced very close to the same o2 concentrations just before the transit began.

Solubility as a function of depth (temperature, pressure, and salinity) would increase solute gradient; not decrease it. And is it not the solute gradient that drives diffusion?

It does not seem reasonable to ignore diffusion as a significant means of vertical O2 transport in the oceans.

Since the convective transit times are so long I would think that diffusion would support a higher transport flux than convection.

What am I missing here?

Diffusion shouldn't be ignored. Fick's law just won't be of much use. Mass flow and variations in solubility for multiple variables makes it far far too simple.

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The transit times are long compared to our lives, but quick compared to significant changes in O2 levels. I can't find anything for more recent history, but indications are that over the past 20 million years O2 levels have increased a few percent. That is the wrong direction, and also far too slow for much difference over a mere 1000 years.

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The main thing that suggests to me the oceans are not masking a change in atmospheric O2 by diffusion is that diffusion is driven by a difference in concentration, so it can' t be an effective mask of change since change is what is required for the action.

II just reviewed the link you posted. It shows a decline in O2 concentration of about 0.01% over about 1/4 century (i.e if it had been at 20.95%, then it would be around 20.94% about 25 years later).

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First off I want to thank you again for sharing your knowledge with me. It is much appreciated.

If ocean and atmospheric O2 are in dynamic equilibrium wouldn't any decrease in atmospheric O2 result in 02 coming out of solution from the ocean?

If that is indeed the case then that very small one hundredth of one percent decrease in atmospheric O2 could be masking a much more significant reduction in unbound O2!

Since the O2 concentration in the ocean is so much less than that of the atmosphere, and if the oceans are helping to sustain O2 concentrations through the process of equilibrium dissolution, wouldn't the unbound O2 depletion in the atmosphere accelerate exponentially as the concentration in ocean solute decreases?

If ocean and atmospheric O2 are in dynamic equilibrium wouldn't any decrease in atmospheric O2 result in 02 coming out of solution from the ocean?

The TENDENCY would be so, yes. Note that there are many variables, of which a number have been mentioned, that dictate the balance point. In all likelihood this point is a moving target as you are looking at it on a macro scale; at any given time one ocean area may be moving downwards while another is moving upwards.

If that is indeed the case then that very small one hundredth of one percent decrease in atmospheric O2 could be masking a much more significant reduction in unbound O2!

No. The important thing to remember, is that equilibrium changes are RESPONSIVE, not predictive. Therefore they lag the disruptive factor and can never overshoot. In order for there to be a larger reduction in unbound O2 it has to be coming from somewhere else- if we take the atmospheric levels as 1.00 and add the ocean capacity as 0.01, that gives us 1.01. A reduction of 0.01% in atmospheric levels would require about 1% reduction in ocean levels to offset it. Note though, that it does NOT mean that it will be happen; in reality the change in ocean levels will be less than the 0.01% value.

Since the O2 concentration in the ocean is so much less than that of the atmosphere, and if the oceans are helping to sustain O2 concentrations through the process of equilibrium dissolution, wouldn't the unbound O2 depletion in the atmosphere accelerate exponentially as the concentration in ocean solute decreases?

???? Please clarify.

JNB:

Thank you for your interesting and informative reply.

"A reduction of 0.01% in atmospheric levels would require about 1% reduction in ocean levels to offset it. Note though, that it does NOT mean that it will be happen; in reality the change in ocean levels will be less than the 0.01% value."

- I see a typo here. Just to make it clear, I understand you to say that given dynamic equilibrium, for each .01% reduction in atmospheric O2 a somewhat less than 1 % reduction of dissolved O2 in the oceans would result? Dang - that's huge. Hopefully I am misunderstanding what you are saying.

Looking at the trend in atmospheric O2 here - http://scrippso2.ucsd.edu/ what percentage reduction in dissolved O2 in the ocean would occur over a 100 year time span?

This is way outside my box so I need to step back and do some more studying before I can wrap my mind around this topic and what you just stated.

Please be patient with me.

While that happens could you share what you believe trending atmospheric O2 shown at the link above means for the ocean solute?

Thank you - Sincerely.

Oxygen depletion would be easily recognisable by yapping ...!

"Good sense" dictates - "Common Sense" is an essay written by Thomas Paine; but the term is often used as an excuse for being and remaining ignorant of issues that require extended effort to understand.

Are you yapping?

If you have some facts that I can be ignorant off come back. Otherwise I say yes to blunder as in "to utter stupidly, confusedly, or thoughtlessly"!

Yapping and learning about Henry's Law as it would apply to net solution and dissolution of O2 between the atmosphere and the ocean.

I am confident that atmospheric O2 levels are decreasing, that given constant consumption the rate of that depletion will increase exponentially as the ocean concentration responds to that atmospheric decrease, and that it would indeed be a blunder if we missed the connection.

I apologize for the remark about the confusion between common sense and good sense. It was a little nasty. Please forgive me.

No worries! I am sure we need to make that connection.

But if the burning of fossil fuels is not the concern, if we are dealing with possibly unknown processes that deplete Oxygen, if we were just there to know why there is an earthquake but we can not prevent it then all we do is we add to our knowledge of our atmosphere. You stated yourself that there was times with 0 up to 35% Oxygen on Earth. So what do we see other than that nothing is static. It moves, it cycles, its changing like it probably always has.

This will need a lot further research and clarification in order to find if it is a real problem. But then people live in the Himalaya so humans will adapt.

If you mean Blunder as in: a gross, stupid, or careless mistake

I guess we will be fine because your weblink proves it is being looked at. So no room for a mistake!

" ----- then all we do is we add to our knowledge of our atmosphere."

Would not that alone be worth the pursuit?

"I guess we will be fine because your weblink proves it is being looked at." --

The link indicates that atmospheric O2 concentrations are declining. There is no mention of related ocean dissolution. The significance here is that ocean to air dissolution is reducing the rate at which O2 concentrations are being lowered in the atmosphere. Wouldn't ocean concentration rates decrease exponentially in relation to atmospheric depletion?

Not if the physics says otherwise!

The physics supports high diffusion rates relative to convective transport times?

Does it say its high or gets exponentially higher?

its been in balance for over 4 billion years just as carbon has been, dont ask me again for a billion years

Atmospheric concentrations have varied between 0 and about 35 percent over that 4 billion years.

Ocean solute concentrations, a clearer indication of trending O2 concentrations than that of the atmosphere, are measurably changing in the time scale of decades, not billions of years.

Perhaps you need to recalibrate your "balance."

Any link for this? Would be interesting to see that this research is being done. Or if the entire focus is on CO2.

If you're that worried about CO2 depletion pop open a bottle beer, let the CO2 bubble out of it, and then drink it. We'll all be better off.

I've tried that and have found that it doesn't change trending ocean solute regardless the scale of my efforts.

Keeping in mind that the solubility of oxygen in water under "normal" conditions is approximately 10 parts per million, at what point is it likely to start coming out?

Thanks for numbers.

So far you guys have encouraged me to gain a better understanding of the occurring reduction in atmospheric O2 partial pressure and Henry's Law as it applies to the dissolution of O2 between the atmosphere and ocean. For me it has been very helpful.

Thank You

Found this interesting link regarding the fish.

Bill Fish lost about 15% of total habitat between 1960 and 2010 due to de-oxygenation.

http://www.nature.com/articles/nclimate1304.epdf?referrer_access_token=P6XTS2Kx1k7IohqFonKmFtRgN0jAjWel9jnR3ZoTv0OGwD93nvwb633Z8KfXxzL3zpzrRkpyioCErjl9ClPOk5D0RPHHo5zo5Q8zkiZhDO8g4_zzr5pd8OART1KVUywXYh-50-1jGA0oBs46hASsMMsf1qk0FPoNf0yaZViqkDI2VaycYevrzJYIwuwfnKnlt7UPjk8_4SPASBQoOOnIsOEqGwPxjS3CthxcBdRp_nqAfxF1UWNvi4TUhQcykOhW&tracking_referrer=news.nationalgeographic.com

This sounds vaguely familiar, almost like a duplicate thread.

Perhaps having the same topic; but most definitely with an evolved understanding of the variables. So much so that can't we claim it as a new thread?

I've always been the "Just Do It" kind of person. Lots of discussion on the where-tos, how's and whys. Lets look at solutions. http://www.carbonify.com/carbon-calculator.htm 8 trees planted offset one persons CO2 footprint. I've already planted enough trees to cover everyone plus who have commented on this already.

I doubt this is the case since I commented and I fuel my fireplace with lots of old unaccounted wood. Plus I drive a big car and I eat beef!

I chopped more trees down than I planted. You need to do some more I guess!