Earths Atmospheric Oxygen Content

[Ant Sinclair]

Below is a link, the part Iam referring to is the section on possible side effects of geo-engineering. If I have read this correctly, as Ozone is reduced more UV Rays can penetrate into earths atmosphere creating new Ozone from our Breathable O2 making O3.

How much Breathable Oxygen could Earth be losing each Year due to this process? ???

 

 

 

http://en.m.wikipedia.org/wiki/Stratospheric_sulfate_aerosols_(geoengineering)

Edited March 11, 2015 by Ant Sinclair

[Greg H.]

Take a gander at the article on the Chapman cycle.

 

The important thing to remember is that Oxygen that combines to form Ozone isn't lost forever. Ozone can (and does) break apart to form O₂ + O when exposed to the proper wavelengths of ultraviolet radiation. (This cycle also produces excess kinetic energy in the form of heat). This is how the Ozone layer does its job of protecting us from high energy uv rays - it absorbs them and breaks apart.

[Strange]

Oxygen makes up about 21% of the atmosphere, while ozone is less than 1 part per million. So you would need to increase the amount of ozone by many thousands of times to have a measurable effect on oxygen levels. (But then you would probably die from exposure to ozone at that level.)

[Ant Sinclair]

And so if Earths atmospheric Oxygen levels were decreasing would it lead to less Ozone being generated and more UV Rays reaching The Earths Surface?

[Strange]

And so if Earths atmospheric Oxygen levels were decreasing would it lead to less Ozone being generated and more UV Rays reaching The Earths Surface?

 

Interesting question. I suspect that because the proportion of oxygen that is converted to ozone is so tiny, there would be no noticeable effect until the amount of oxygen had been reduced drastically (and by then you would have other problems: like breathing!)

 

But this might be dependent on how oxygen is mixed in the upper atmosphere, which I don't know anything about.

[Greg H.]

And so if Earths atmospheric Oxygen levels were decreasing would it lead to less Ozone being generated and more UV Rays reaching The Earths Surface?

Actually it wouldn't take much of a change in Oxygen concentration to kill humans.

 

The Occupational Health and Safety Administration has done quite a lot in the area of Oxygen levels in confined spaces, as it relates to worker safety. Turns out that once the oxygen content in the atmosphere drops below about 19.5%, your blood is no longer carrying as much Oxygen as it can (it's no longer at saturation). How that would affect Ozone production, I'm not entirely sure, but I have a feeling we'd have larger issues, as Strange points out.

 

The bigger issue in terms of Ozone production is artificial depletion due to chemicals in the upper atmosphere. These artificially break up ozone molecules - effectively skipping the part where it absorbs that uv ray, which allows more of the high energy rays to reach the ground.

[Ant Sinclair]

Thank You both for Your replies.

Would You know of any monitoring being done on the altitude levels Oxygen is at presently, and over the last few decades, or any other indications of the amount of atmospheric Oxygen from a few decades ago up-to the present day?

[Strange]

Here is one: http://www.esrl.noaa.gov/gmd/obop/mlo/programs/coop/scripps/o2/o2.html

 

There may be others.

[Ant Sinclair]

This was an article in the Guardian News Paper as regards falling O2 levels on Earth and a couple of excerpts from it, the link at the bottom of page is to the article;

 

 

Much of this recent, accelerated change is down to human activity, notably the industrial revolution and the burning of fossil fuels. The Professor of Geological Sciences at Notre Dame University in Indiana, J Keith Rigby, was quoted in 1993-1994 as saying:

 

"In the 20th century, humanity has pumped increasing amounts of carbon dioxide into the atmosphere by burning the carbon stored in coal, petroleum and natural gas. In the process, we've also been consuming oxygen and destroying plant life cutting down forests at an alarming rate and thereby short-circuiting the cycle's natural rebound. We're artificially slowing down one process and speeding up another, forcing a change in the atmosphere "

 

Very interesting. But does this decline in oxygen matter? Are there any practical consequences that we ought to be concerned about? What is the effect of lower oxygen levels on the human body? Does it disrupt and impair our immune systems and therefore make us more prone to cancer and degenerative diseases?

 

Surprisingly, no significant research has been done, perhaps on the following presumption: the decline in oxygen levels has taken place over millions of years of our planet's existence. The changes during the shorter period of human life have also been slow and incremental until the last two centuries of rapid urbanisation and industrialisation. Surely, this mostly gradual decline has allowed the human body to evolve and adapt to lower concentrations of oxygen? Maybe, maybe not.

The story at sea is much the same. Nasa reports that in the north Pacific ocean oxygen-producing phytoplankton concentrations are 30% lower today, compared to the 1980s. This is a huge drop in just three decades.

 

The argument for divesting from fossil fuels is becoming overwhelming.

 

http://www.theguardian.com/commentisfree/2008/aug/13/carbonemissions.climatechange

I don't know the date when NASA had alledgedly stated that Phytoplankton had been reuced by 30% but if it was pre - Fukushima as UV Rays kill Phytoplankton wouldn't Fukushimas' contiued radio - active pollution do the same?

[swansont]

I don't know the date when NASA had alledgedly stated that Phytoplankton had been reuced by 30% but if it was pre - Fukushima as UV Rays kill Phytoplankton wouldn't Fukushimas' contiued radio - active pollution do the same?

 

!

Moderator Note

We're not bringing Fukushima into this thread, too. That's being discussed elsewhere.

[Strange]

I don't know the date when NASA had alledgedly stated that Phytoplankton had been reuced by 30% but if it was pre - Fukushima as UV Rays kill Phytoplankton wouldn't Fukushimas' contiued radio - active pollution do the same?

 

I can't find a source for this 30% - there seem to be a lot of people repeating it (many of them very dubious sources, such as conspiracy theory forums). The nearest I could find is: http://www.nasa.gov/centers/goddard/news/topstory/2003/0815oceancarbon.html

Which says:

 

rates of plankton growth declined by 7

percent in the North Atlantic basin, 9 percent in the North

Pacific basin, and 10 percent in the Antarctic basin when

comparing the 1980s dataset with the late 1990s observations.

 

So nowhere near 30%. It does say:

 

nearly 70 percent of the NPP global decline

per decade occurred in the high latitudes

So I suppose someone might have totally misunderstood that.

 

Why do you think UV has anything to do with it? And why would the minute amount of radiation from Fukushima have any effect (don't answer that: you have another thread on that topic, which I am avoiding).

[Ant Sinclair]

The post swansont is on this thread - Earths Atmospheric Oxygen Content, and as such phytoplankton produce O2 , therefore as such would have a bearing on O2 production and earths atmospheric Oxygen content, if ultra violet radiation kills phytoplankton as would Cesium137 too then this affects the earths O2 volumes. Iam sorry if in My logic in this isn't correct assumption.

I can't find a source for this 30% - there seem to be a lot of people repeating it (many of them very dubious sources, such as conspiracy theory forums). The nearest I could find is: http://www.nasa.gov/centers/goddard/news/topstory/2003/0815oceancarbon.html

Which says:

 

 

So nowhere near 30%. It does say:

 

So I suppose someone might have totally misunderstood that.

 

Why do you think UV has anything to do with it? And why would the minute amount of radiation from Fukushima have any effect (don't answer that: you have another thread on that topic, which I am avoiding).

Strange I havn't found that exact NASA quote My self but will look later, if phytoplankton is being damaged by Fukushima and other enviromental issues, on top of that We have deforrestation etc then when as I read a while ago that at one point China was commissioning a coal fired power station at the rate of one a week, wouldn't all these issues work in synergetic way in lowering Earths Atmospheric Oxygen Content?

[swansont]

The post swansont is on this thread - Earths Atmospheric Oxygen Content, and as such phytoplankton produce O2 , therefore as such would have a bearing on O2 production and earths atmospheric Oxygen content, if ultra violet radiation kills phytoplankton as would Cesium137 too then this affects the earths O2 volumes. Iam sorry if in My logic in this isn't correct assumption.

 

!

Moderator Note

 

You have a thread on whether Fukushima is affecting the ocean.

http://www.scienceforums.net/topic/88126-damage-being-done-to-the-pacifics-eco-system-due-to-the-fukushima-incident

 

You can discuss the effect of lowering phytoplankton. You weren't discussing the cause for the 30% claim, so causes is apparently not an issue. Discussing Fukushima as the alleged cause is OT for this thread.

 

This is not a negotiation, and don't respond to this in the thread.

 

[StringJunky]

Indigenous high-altitude people happily live in oxygen concentrations down to about 11%. (16 728ft altitude). The longest anyone can survive at 7% (26 000ft) is about 48 hours. With appropriate acclimatisation people can be quite hardy.

[Ant Sinclair]

Indigenous high-altitude people happily live in oxygen concentrations down to about 11%. (16 728ft altitude). The longest anyone can survive at 7% (26 000ft) is about 48 hours. With appropriate acclimatisation people can be quite hardy.

Is Oxygen Content at that altitude getting lower?, and if it, is by how much?

Is anybody checking?

Edited March 23, 2015 by Ant Sinclair

[StringJunky]

Is Oxygen at that altitude getting lower?, and if it, is by how much?

Is anybody checking?

AFAIK the ratio of oxygen stays the same at whatever altitude, there is just less total molecules available higher up. If it's going down here, it will go down in the proportion same up there. I don't know if the total oxygen level is going down or not.

Edited March 23, 2015 by StringJunky

[Endy0816]

@OP: Might want to look into ocean acidification. Increased CO2 production is widespread and ongoing. That is why it is more a concern than relatively minor transient events.

 

Indigenous high-altitude people happily live in oxygen concentrations down to about 11%. (16 728ft altitude). The longest anyone can survive at 7% (26 000ft) is about 48 hours. With appropriate acclimatisation people can be quite hardy.

 

and this Florida boy managed to climb Pike's Peak. Most of you all are at higher elevations in our ocean of air and so should be just fine.

[Ant Sinclair]

I would have thought that Oxygen content in Earths Atmosphere would be something science would look at as it is quite an important gas to Man and most life on Earth, like Peter said in His Guardian News Paper article "I found it surprising no one is looking at this".

[StringJunky]

I would have thought that Oxygen content in Earths Atmosphere would be something science would look at as it is quite an important gas to Man and most life on Earth, like Peter said in His Guardian News Paper article "I found it surprising no one is looking at this".

You don't know what you've got 'til it's gone.

[pavelcherepan]

Surprisingly, no significant research has been done, perhaps on the following presumption: the decline in oxygen levels has taken place over millions of years of our planet's existence.

 

There's some research if you look hard enough.

 

Here's the oxygen concentrations measured at Cape Grim for the last couple decades (btw, who knows what is the unit 'per meg'?)

 

 

Here's the general oxygen levels trend for the last billion years:

 

 

And the reason why not much research has been done on recent anthropogenic effects is probably hidden in this quote:

 

 

 

Whilst human activities, such as the burning of fossil fuels, have an impact on relative carbon dioxide concentrations, their impact on the much larger concentration of oxygen is less significant.

 

 

[Acme]

There's some research if you look hard enough.

 

Here's the oxygen concentrations measured at Cape Grim for the last couple decades (btw, who knows what is the unit 'per meg'?)

 

...

Scripps knows.

 

Units and Terms

Per Meg Units

 

We report oxygen measurements as changes in the O2/N2 ratio of air relative to a reference. We compute

 

δ = ((O2/N2)sample (O2/N2)reference)/ (O2/N2)reference)

 

where (O2/N2)sample is the O2/N2 mole ratio of an air sample and (O2/N2)reference is the O2/N2 mole ratio of our reference. Our reference is based on tanks of air pumped in the mid 1980s which we store in our laboratory.

 

The quantity δ is zero if the sample has the same O2/N2 ratio as the reference and negative if the sample has a lower ratio than the reference. δ values of air samples collected today are negative because the O2/N2 ratio of the air has decreased since the 1980s.

 

The changes we observe in the O2/N2 ratio are tiny. Typical air in 2008 had δ a value of around -0.000400. The decrease from year to year is around -0.000020. We could multiply δ by 100 and report δ in percent units, or multiplying by 1000 and report in permil units. But because the changes in δ are so small, we instead multiply δ by 1000000 and express δ in per meg units. Thus -0.000400 equals -400 per meg. One per meg equals 0.001 permil or 0.0001 percent.

...

[StringJunky]

 

....btw, who knows what is the unit 'per meg'?)

 

http://scrippso2.ucsd.edu/units-and-terms. In that same site it says we are losing about 19 O ₂ molecules/million/year. Assuming no other effects, that gives us 46 842 years for the concentration drop to 11%. This is what will be survivable near sea level.

 

Edit: acme beat me

Edited March 24, 2015 by StringJunky

[pavelcherepan]

http://scrippso2.ucsd.edu/units-and-terms. In that same site it says we are losing about 19 O ₂ molecules/million/year. Assuming no other effects, that gives us 46 842 years for the concentration drop to 11%. This is what will be survivable near sea level.

 

Edit: acme beat me

 

StringJunky, I got different value from what you calculated. The way I understood what they said we lose 19 per 1,000,000 molecules of oxygen and so getting to 11% oxygen concentration requires losing almost half ~476190 molecules, which makes it ~25063 years. Or did I go wrong somewhere?

Edited March 24, 2015 by pavelcherepan

[StringJunky]

 

StringJunky, I got different value from what you calculated. The way I understood what they said we lose 19 per 1,000,000 molecules of oxygen and so getting to 11% oxygen concentration requires losing almost half ~476190 molecules, which makes it ~25063 years. Or did I go wrong somewhere?

We are losing 19 oxygen molecules, per million oxygen molecules, per year. We know, from my post, the lowest survivable level is 11%. So, 100% - 11% = 89%. 89% of 1 million is 890 000. We need to find how many 19's go into 890 000 which will give the number of years to use up 89%. 46 842 years.

Edited March 24, 2015 by StringJunky

[pavelcherepan]

We are losing 19 oxygen molecules, per million oxygen molecules, per year. We know, from my post, the lowest survivable level is 11%. So, 100% - 11% = 89%. 89% of 1 million is 890 000. We need to find how many 19's go into 890 000 which will give the number of years to use up 89%. 46 842 years.

 

But that 1 million molecules of oxygen represents the current concentration in the atmosphere of 21%. Then in order to get to 11% of atmospheric concentration is

 

1,000,000 - ((11%/21%)*1,000,000) = 476190 O₂ molecules needs to be lost per 1 million.

Edited March 24, 2015 by pavelcherepan