Air bubbles in Antarctic ice point to cause of oxygen decline

Glacial erosion likely caused atmospheric oxygen levels to dip over past 800,000 years

Peer-Reviewed Publication


Yuzhen Yan in Antarctica

Photo courtesy of Yuzhen Yan

HOUSTON – (Dec. 20, 2021) – An unknown culprit has been removing oxygen from our atmosphere for at least 800,000 years, and an analysis of air bubbles preserved in Antarctic ice for up to 1.5 million years has revealed the likely suspect.

“We know atmospheric oxygen levels began declining slightly in the late Pleistocene, and it looks like glaciers might have something to do with that,” said Rice University’s Yuzhen Yan, corresponding author of the geochemistry study published in Science Advances. “Glaciation became more expansive and more intense about the same time, and the simple fact that there is glacial grinding increases weathering.”

Weathering refers to the physical and chemical processes that break down rocks and minerals, and the oxidation of metals is among the most important. The rusting of iron is an example. Reddish iron oxide forms quickly on iron surfaces exposed to atmospheric oxygen, or O2.

“When you expose fresh crystalline surfaces from the sedimentary reservoir to O2, you get weathering that consumes oxygen,” said Yan, a postdoctoral research associate in Rice’s Department of Earth, Environmental and Planetary Sciences.

Another way glaciers could promote the consumption of atmospheric oxygen is by exposing organic carbon that had been buried for millions of years, Yan said.

During Yan’s Ph.D. studies in the labs of Princeton University’s Michael Bender and John Higgins, Yan worked on a 2016 study led by Daniel Stolper, now an assistant professor at the University of California, Berkeley, that used air bubbles in ice cores to show the proportion of oxygen in Earth’s atmosphere had declined by about 0.2% in the past 800,000 years.

In the Science Advances study, Yan, Higgins and colleagues from Oregon State University, the University of Maine and the University of California, San Diego, analyzed bubbles in older ice cores to show the O2 dip began after the length of Earth’s glacial cycles more than doubled around 1 million years ago.

The ice age Earth is in today began about 2.7 million years ago. Dozens of glacial cycles followed. In each, ice caps alternately grew, covering up to a third of the planet, and then retreated toward the poles. Each cycle lasted around 40,000 years until about 1 million years ago. At roughly the same time atmospheric oxygen began to decline, glacial cycles began lasting about 100,000 years.

“The reason for the decline is the rate of O2 being produced is lower than the rate of O2 being consumed,” Yan said. “That’s what we call the source and the sink. The source is what produces O2, and the sink is what consumes or drags on O2. In the study, we interpret the decline to be a stronger drag on O2, meaning more is being consumed.”

Yan said Earth’s biosphere didn’t contribute to the decline because it is balanced, drawing as much O2 from the atmosphere as it produces. Weathering, on a global scale, is the most likely geological process capable of consuming enough excess O2 to account for the decline, and Yan and colleagues considered two scenarios for increased weathering.

Global sea level falls when glaciers are advancing and rises when they retreat. When the length of glacial cycles more than doubled, so did the magnitude of swings in sea level. As coastlines advanced, land previously covered by water would have been exposed to the oxidizing power of atmospheric O2. 

“We did some calculations to see how much oxygen that might consume and found it could only account for about a quarter of the observed decrease,” Yan said.

Because the extent of ice coverage isn’t precisely known for each glacial cycle, there’s a wider range of uncertainty about the magnitude of chemical weathering from glacial erosion. But Yan said the evidence suggests it could draw enough oxygen to account for the decline.

“On a global scale, it’s very hard to pinpoint,” he said. “But we did some tests about how much additional weathering would be needed to account for the O2 decline, and it’s not unreasonable. Theoretically, it could account for the magnitude of what’s been observed.”

Additional co-authors include Edward Brook of Oregon State, Andrei Kurbatov of the University of Maine and Jeffrey Severinghaus of UC San Diego. The research was supported by the National Science Foundation (1443263, 1443276, 1443306, 0538630, 0944343, 1043681 and 1559691) and a Poh-Hsi Pan Postdoctoral Fellowship from Rice University. 


Read the Science Advances paper, “Ice core evidence for atmospheric oxygen decline since the mid-Pleistocene transition,” at

High-resolution IMAGES are available for download at:
CAPTION: Yuzhen Yan in Antarctica in December 2015. (Photo courtesy of Yuzhen Yan)
CAPTION: Researchers studied Earth’s ancient atmosphere by capturing tiny bubbles of air that were preserved in Antarctic ice for up to 1.5 million years. (Photo by Yuzhen Yan)
CAPTION: A scientific drilling mission to Allan Hills, East Antarctica, in 2015-16 yielded ice cores with trapped bubbles of ancient air, including some that predated the ice age that began 2.7 million years ago. (Photo by Yuzhen Yan)

This release can be found online at

Follow Rice News and Media Relations via Twitter @RiceUNews.

Located on a 300-acre forested campus in Houston, Rice University is consistently ranked among the nation’s top 20 universities by U.S. News & World Report. Rice has highly respected schools of Architecture, Business, Continuing Studies, Engineering, Humanities, Music, Natural Sciences and Social Sciences and is home to the Baker Institute for Public Policy. With 4,052 undergraduates and 3,484 graduate students, Rice’s undergraduate student-to-faculty ratio is just under 6-to-1. Its residential college system builds close-knit communities and lifelong friendships, just one reason why Rice is ranked No. 1 for lots of race/class interaction and No. 1 for quality of life by the Princeton Review. Rice is also rated as a best value among private universities by Kiplinger’s Personal Finance.


Science Advances




Experimental study


Not applicable


Ice core evidence for atmospheric oxygen decline since the mid-Pleistocene transition



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December 20, 2021 10:14 pm

“Yan said Earth’s biosphere didn’t contribute to the decline because it is balanced, drawing as much O2 from the atmosphere as it produces.”

If this is the case where did the excess oxygen in the atmosphere come from?

Mike Dubrasich
Reply to  Terry
December 20, 2021 10:52 pm

Free O2 is produced by photosynthesis from the precursor, atmospheric CO2. There is no other source. O2 is removed by oxidation, i.e. rusting, decay, or burning.

During the Pleistocene CO2 concentrations have dropped to their lowest levels in a quarter of a billion years. That plus the extreme cold has reduced global photosynthesis.

Thus the source of free O2 has declined. The authors’ assumption falling O2 levels is due to the sink increasing rather than the source declining seems to be exactly wrong.

Richard Page
Reply to  Mike Dubrasich
December 21, 2021 2:44 am

But is in line with climastrology – he’s still on message. I agree with you and, in fact, that was the first thing I thought of when I saw the headline.

Joao Martins
Reply to  Mike Dubrasich
December 21, 2021 3:19 am

No, Mike!

Atmospheric oxygen comes from WATER, not from CO2!!!

This is basic photosynthesis, elucidated many, many decades ago!

Oxygen from atmospheric CO2 is fixed, through photosynthesis, in carbohydrates. The energy of light is used to split water molecules, freeing gaseous oxygen and keeping the hydrogen to be combined with CO2 in the synthesis of carbohydrates.

Last edited 1 year ago by Joao Martins
Phil Rae
Reply to  Joao Martins
December 21, 2021 4:11 am

Correct! I was gonna pitch in but you got there before me. Water is indeed the source of oxygen in photosynthesis.

Reply to  Joao Martins
December 21, 2021 6:20 am

He is correct that ALL oxygen in the atmosphere is produced by photosynthesis which requires CO2 and sunlight as inputs to the reaction. Water does not auto-generate oxygen, elsewise for those billions of years before the Earth’s atmosphere lacked significant oxygen, it was at the same time covered with water.

Joao Martins
Reply to  Duane
December 21, 2021 7:03 am

No! As everywhere, words matter! If we need to confront people that mislead by distorting scientific assertions, we MUST be accurate! Sorry, what Mike has written is completely clear and wrong: “Free O2 is produced by photosynthesis from the precursor, atmospheric CO2“.

And thus he is further wrong when elaborating on a tentative explanation of oxygen decrease as a source-sink system: “During the Pleistocene CO2 concentrations have dropped (…) Thus the source of free O2 has declined” (sic; my italics). This is wrong: CO2 IS NOT the source of atmospheric O2!

Sorry, you, Duane, are also wrong, by omission: “ALL oxygen in the atmosphere is produced by photosynthesis which requires CO2, water and sunlight as inputs to the reaction”. Water is one of the inputs of photosynthesis.

And please mind your arguments: “Water does not auto-generate oxygen” is the same as saying that coal and petrol do not produce CO2 by themselves: what would you like to prove with this assertion?

Last edited 1 year ago by Joao Martins
Mike Dubrasich
Reply to  Joao Martins
December 21, 2021 9:35 am

Whoops. My bad. You are technically correct. In the RuBisCO enzyme CO2 is fixed to lysine forming a carbamate, LysNHCOO-, the first step in Life. In addition, or concurrently, water molecules are split into free Oxygen and hydroxyl ions. So technically the O2 comes from water…

…by way of photosynthesis, which requires CO2. No CO2, no photosynthesis, no oxygen production. Duane is also correct in that water does not auto-generate O2.

If not for photosynthesis, Earth would have no life and no O2 to breathe. It’s kind of a miracle. I know some of you believe RuBisCO, a peptide with over 5,000 amino acids in exact order, was formed by random accident in the primordial goo, but that seems farfetched to me.

In any case, when CO2 levels are low and photosynthesis is constrained by ice and cold, O2 production declines. The authors missed that factoid.

Reply to  Mike Dubrasich
December 21, 2021 5:55 pm

Technically the water comes from photosyntheses of CO2 and sunlight. That intermediate biochemical reactions occur within the photosynthesis is irrelevant.

You guys are engaging in pointless pedantry. Your arguments are equivalent to claiming that gasoline or diesel fuel do not power internal combustion engines because there are intermediate processes involved in vaporizing the fuel, metering its supply to maintain the required fuel-air mixture, ignition processes, and complex mechanical processes to convert the heat energy to mechanical energy at the wheels. None of those intermediate process change the fact that fossil fuel is the necessary precursor to production of mechanical power via an internal combustion engine.

SMH for gods sakes!

Reply to  Joao Martins
December 21, 2021 5:46 pm

No he is correct and YOU are both wrong and tiresome pedant. Facts DO matter

Oxygen molecules in the atmosphere most certainly ARE produced mostly from photosynthesis, for which photosynthesis process CO2 as well as sunlight most certainly ARE precursors.

C’mon genius produce your proof that water auto generates oxygen gas … of course you cannot.

Oxygen and hydrogen are tightly bound in water molecules, and it takes a large external energy input to break those bonds. Such as the electrical energy input in “electrolysis”. Water cannot produce it’s own energy to break those binds any more than you can reproduce yourself asexually.

You know less about chemistry than the average sixth grader. Stop embarrassing yourself.

Joao Martins
Reply to  Duane
December 22, 2021 1:01 pm

Sorry, Duane, perhaps I know more of chemistry and biochemistry than you imagine, certainly more than what you know; but this is not the point, I am not here in a school competition.

You did not address my comments, but started an ad hominem rant; this speaks about you and your character. And also about your intelligence and knowledge: if you studied a bit more that the 6th grade of plant biology you would have understood what I said and would have shut up.

So, I will not dignify your ignorant (of chemistry and of the English language) verbal diarrhea by answering it.

P.S.: By the way, it was actually when I was in my 5th grade, long ago (65 years, you figure…), that my teacher told us in the classroom: “Your manual says that the oxygen liberated by photosynthesis comes from the carbon dioxyde; but that is not true, it comes from water”. And then he explained to us how photosynthesis works

Last edited 1 year ago by Joao Martins
Reply to  Duane
December 21, 2021 10:10 am

You’re right, Duane — Joao is technically correct, but also being unnecessarily semantic. Bottom line is, if not for photosynthesis, which requires CO2, water is not going to release O2 by itself. CO2 is a required part of the process.

Reply to  beng135
December 21, 2021 5:58 pm

These guys are like the proverbial biblical Pharisees arguing incessantly over how many angels can dance on the head of a pin.

Reply to  Duane
December 24, 2021 7:33 pm

OMG you are incorrect about photosynthesis, and then compound your errors by mixing up Pharisees and Scholastic scholars, and also mis-attributing them (?) as that bit about “how many angels can dance on the head of a pin” was NOT even a minor focus of Scholastic scholars, but a jab at them invented by later secular scholars.

Joao Martins
Reply to  beng135
December 22, 2021 1:05 pm

Yes, beng, probably the alarmists are right, and that connection between CO2 and warming in nothing more than unnecessary semantics… nice scientific skeptical approach, thank you, i’ll make a note of it…

Reply to  Joao Martins
December 21, 2021 11:49 am

6 CO2 + 6 H2O + energy –> C6H12O6 + 6 O2

That equation is the way that photosynthesis is portrayed in almost any place where you might look it up. It’s only when you get into the intermediate steps, as the entire process does its thing, that you can see which molecules the oxygen actually comes from. (Half do come from the CO2.)

Reply to  writing observer
December 21, 2021 2:40 pm

Also, if the source (photosynthesis) was reduced, and sinks remained the same, or got bigger, O2 levels would decrease.

Reply to  Thomas
December 21, 2021 2:42 pm

Nevertheless, it is an interesting finding. Although, as the author states, “Theoretically, it could account for the magnitude of what’s been observed.” So it’s speculation and guessing, but sitll interesting.

Reply to  Thomas
December 21, 2021 5:03 pm

It’s barely at the level of “hypothesis.” Unlikely it will get much higher.

Joao Martins
Reply to  writing observer
December 22, 2021 1:27 pm

No: ALL comes from water. See comment by Alfred Robert Taylor at December 21, 2021 1:38 pm.

And ALL the oxygen in CO2 is fixed in carbohydrates.

You have written down the GLOBAL equation of photosynthesis. But photosynthesis is not a chemical process, it is a biochemical process achieved through many individual reactions, whose sum is the equation you cite.

Without entering in great detail, we can separate it in two “steps” which are coupled: a “light reaction” and a “dark reaction”. The first needs light, and the energy of light is used to split the water molecules. Then several chemical steps transfer the protons (hydrogen nuclei) and combine them with CO2 to make carbohydrates. But as everywhere in biochemistry, this is just the summary of a rather complex process.

Last edited 1 year ago by Joao Martins
michael hart
Reply to  Mike Dubrasich
December 21, 2021 5:02 am

That was indeed my first though, Mike Dubrasich. That the author didn’t even appear to mention this, says a lot.

michael hart
Reply to  michael hart
December 21, 2021 5:03 am

that’s first “thought”, not first “though”

Robert Alfred Taylor
Reply to  Mike Dubrasich
December 21, 2021 1:38 pm

O2 is NOT produced from CO2 by photosynthesis! It was proven in the 1950’s by Samuel Ruben and Martin Kamen that the O2 comes from water. Once upon a time this was taught in high school science classes.:
2 H2O + 2 A + (light, chloroplasts) → 2 AH2 + O2
A is the electron acceptor. Therefore, in light, the electron acceptor is reduced and oxygen is evolved. Samuel Ruben and Martin Kamen used radioactive isotopes to determine that the oxygen liberated in photosynthesis came from the water.

Reply to  Robert Alfred Taylor
December 21, 2021 6:02 pm

Meaningless argument. Nearly sll atmospheric oxygen is produced from photosynthesis of CO2 and sunlight. The fact that there are biochemical intermediate reactions that occur with photosynthesis does not change the fact that CO2 and sunlight are necessary precursors, along with water. Water cannot self dissociate into molecular oxygen and hydrogen.

Joao Martins
Reply to  Robert Alfred Taylor
December 22, 2021 1:10 pm

Thank you. At least you got it right.

We cannot change biochemistry (yes, this is NOT chemistry) and take the natural processes not how they are but how we think or imagine they are…

Reply to  Joao Martins
December 24, 2021 8:37 am

To say biochemistry is NOT Chemistry is idiotic. It sure as hell is not magic. It involves chemical changes, therefore it is chemistry!

Robert Alfred Taylor
Reply to  Mike Dubrasich
December 21, 2021 1:43 pm

Some O2 is also produced by photodisassociation of H2O, CO2, etc. Thus the O2 found in the atmospheres of various other solar system bodies, and the early atmosphere of Earth.

Mike Dubrasich
Reply to  Robert Alfred Taylor
December 21, 2021 4:41 pm

No. The earliest geologic eon was the Hadean, 4.6-4.0 bya, and there was no atmospheric O2 (or oceans for that matter). Then came the Archean eon, 4.0-2.5 bya, when the cooling Earth first formed oceans and continents. The last era in the Archaen was the Neoarchaen, 2.8-2.5 bya, when cyanobacteria began oxygenic photosynthesis. There was no free O2 in the atmosphere until the Neoarchaen era.

“The Proterozoic eon began about 2.5 billion years ago and ended about 500 million years ago when the first complex lifeforms appeared. During this period, the Great Oxygenation Event transformed the Earth’s atmosphere, allowing for the evolution of aerobic organisms.” [here]

Robert Alfred Taylor
Reply to  Mike Dubrasich
December 22, 2021 6:04 pm

What you wrote is the traditional view. It applies to significant percentages. I did not save the references, but have read, from sources I consider reliable. What I wrote is elementary photo-chemistry. Given gaseous oxides and ultraviolet light, some amount of O2 will be produced, and a reasonably stable small fraction of a percent will always be present.

Michael S. Kelly
Reply to  Robert Alfred Taylor
December 21, 2021 6:03 pm
Reply to  Robert Alfred Taylor
December 21, 2021 6:05 pm

Oxygen is one of the most common elements in the universe and exists everywhere.. But molecular oxygen gas does not exist on Earth unless released via one or more chemical reactions, such as occurs in photosynthesis.

Reply to  Mike Dubrasich
December 21, 2021 4:52 pm

in the triassic geological time CO2 was circa 5000ppm and the cretaceous geological period the earth was covered in plants etc producing large quantities of CO2 (2400ppm) so the oxygen would be correspondingly higher as more land mass and more plants

always write your conclusion then fit your research to prove it

oh no it doesn’t work – well write it any way because you have your grant conditions to fill

Reply to  Terry
December 20, 2021 11:24 pm

… where did the excess oxygen in the atmosphere come from?

Well, there was the first mass extinction, known as the Great Oxygen Catastrophe.

It’s all the fault of our single-celled ancestors, so we’re guilty. Humans are responsible for everything evil don’tchaknow. /sarc

The other thing is that the oceans contain way more CO2 than the atmosphere. Shouldn’t that also be the case for oxygen?

Ocean temperature changes the solubility of gases. Any analysis that doesn’t take that into account is incomplete.

Loren Wilson
Reply to  commieBob
December 21, 2021 5:27 am

The high amount of CO2 held in the oceans is due to the chemical equilibria between molecular CO2 dissolved in the water, carbonic acid, bicarbonate ion, and carbonate ion. The actual solubility of carbon dioxide in water (without any chemical reaction) is not much higher than oxygen, which is 10-20 ppm in sea water.

Reply to  Terry
December 21, 2021 12:10 am

I would really like to see the ‘proof’ for the statement of ‘balanced’, since I find hard to simply accept it out of blind religious faith. An assumption of equilibrium for something in a system that’s not at equilibrium should be verified. Throwing an ipse dixit is simply not enough.

Jay Willis
Reply to  Adrian
December 21, 2021 3:17 am

Yes thats exactly what I thought. “Yan said Earth’s biosphere didn’t contribute to the decline because it is balanced,”

This is a problematic statement.

Reply to  Jay Willis
December 21, 2021 4:22 am

its propaganda. the climate jackals push the narrative that earth systems are in balance and human activity unbalances them. its always the damn humans. lol earth systems are the opposite of balanced.

from merriam-webster
Essential Meaning of balance
1 : the state of having your weight spread equally so that you do not fall He held on to the rail for balance. = He held on to the rail to keep/maintain his balance. She had trouble keeping her balance as the boat rocked back and forth. See More Examples
2 : the ability to move or to remain in a position without losing control or falling Gymnasts need flexibility and balance. She has a good sense of balance.
3 : a state in which different things occur in equal or proper amounts or have an equal or proper amount of importance Temperature changes could upset the delicate balance of life in the forest. To lose weight you need the proper/right balance of diet and exercise.

if you want to see what balanced looks like, get a telescope and look at mars.

Rich Davis
Reply to  Jay Willis
December 21, 2021 12:59 pm

What is the hidden agenda I wonder? I can’t see the dots to connect leading us to a conclusion of climate emergency.

One other thing that doesn’t make sense to me is why lower sea level should result in oxidation that would not already occur from oxygen dissolved in the ocean.

Joseph Zorzin
Reply to  Terry
December 21, 2021 3:32 am
Reply to  Terry
December 21, 2021 8:47 am

Biosphere in balance – BS!
All this grant money (from taxpayers) for chasing an apparent 0.2% change in atmospheric O2 over 800,000 years

Color me underwhelmed

I demand a refund

December 20, 2021 11:12 pm

“Why is there oxygen in the atmosphere? The high school explanation is ‘photosynthesis.’ But we’ve known for a long time … that building up oxygen requires the formation of rocks like black shale.”

Joao Martins
Reply to  Pablo
December 21, 2021 3:24 am

” … building up oxygen requires the formation of rocks like black shale …

In another planet/solar system/universe, perhaps…

Pablo, did you not see the question mark at the end of the tatle of that article? If you did not, please consult urgently with an ophthalmologist…

Reply to  Joao Martins
December 21, 2021 5:13 am

see also:

“The major long-term source of oxygen to the atmosphere is the burial of organic carbon in sedimentary rocks (which represents the net flux of photosynthesis minus various pathways of respiration and oxidation).”


Joao Martins
Reply to  Pablo
December 21, 2021 7:19 am

See also the old tale of the hen and the egg, what was the first to appear.

But, I’m sorry, it does NOT apply, not even mataphoricaly, in here. Just because first there was photosynthesis and production of organic matter: it goes without saying that, without organic matter there is no “organic carbon burial”…

Reply to  Pablo
December 21, 2021 6:22 am

Those rocks existed and weathered for billions of years before the atmosphere had any significant oxygen concentration.

It is photosynthesis that produces the oxygen in the atmosphere.

Reply to  Duane
December 21, 2021 6:53 am

from the last link:

“Our model can only reproduce Paleozoic geochemical data if the rise of the earliest land plants caused a major oxygenation event of the Earth’s atmosphere and oceans by ∼400 Ma. We attribute this mid-Paleozoic oxygenation event to a persistent global increase in organic carbon burial supported by the high C/P ratio of early land plant material, augmented by a plant-driven increase in P weathering flux relative to the weathering flux of alkalinity. The δ13C record suggests this increase in organic carbon burial was essentially permanent, producing a new dynamically stable state for atmospheric O2. In this new steady state, oxidative weathering was increased (becoming less sensitive to variations in O2) and new fire-mediated negative feedbacks on O2 were instigated that have played a key role in stabilizing atmospheric O2 concentration up to the present day (2243). For the earliest land plants to be responsible for such a major mid-Paleozoic oxygenation event requires that they were much more productive and globally extensive than has been previously assumed (71033). This hypothesis makes testable predictions with regard to effects on other biogeochemical cycles, notably sulfur; if it stands up to further scrutiny, we can then infer that the earliest land plants created a stable oxygen-rich atmosphere that was necessary for the subsequent evolution of large, mobile, intelligent animals with a high respiratory oxygen demand, including ourselves.”

Mike Dubrasich
Reply to  Pablo
December 21, 2021 9:39 am

“… the earliest land plants created a stable oxygen-rich atmosphere that was necessary for the subsequent evolution of large, mobile, intelligent animals with a high respiratory oxygen demand, including ourselves.”


Reply to  Mike Dubrasich
December 21, 2021 10:04 am

“We attribute this mid-Paleozoic oxygenation event to a persistent global increase in ORGANIC CARBON BURIAL supported by the high C/P ratio of early land plant material, ..”

December 20, 2021 11:16 pm

Ah that infamous “balanced” scenario. Balance is purely a human construct.

Joao Martins
Reply to  lee
December 21, 2021 3:25 am

Yes! Very few people understand that, unfortunately…

Zig Zag Wanderer
December 20, 2021 11:22 pm

Definitely complete bunkum. Not a single mention of CO2. I’m amazed that it got published.

December 21, 2021 12:44 am

Yan and colleagues considered two scenarios for increased weathering.”

Argumentum ad ignorantiam (argument to ignorance): We don’t conceive any other process, so our claim must be true…

Ben Vorlich
Reply to  ATheoK
December 21, 2021 5:52 am

The Sherlock Holmes Fallcy
When you have eliminated all which is impossible, then whatever remains, however improbable, must be the truth.

I’ve always thought there are two issues, first you don’t know for certain everything is impossible, second you don’t if there are any unknowns.

Ron Long
December 21, 2021 2:12 am

The key, and alarming, point here for me is the decline of atmospheric oxygen coordinated with (not a proof of cause and effect, but sufficient to investigate) onset of a change in the Ice Age we live in, wherein the glacial cycles more than doubled in time of duration. This might lead us to pushing more CO2 into the atmosphere and “helping” photosynthesis processes to convert it to oxygen (O2). At my age this does not strike me as a problem.

Richard S Courtney
Reply to  Ron Long
December 21, 2021 2:55 am

Ron Long,

The key, and alarming, point here for me is that this ludicrous paper was not rejected by peer review and so was published. The paper relies on two severe errors of logic when either of those errors alone is sufficient to reject the paper.

As others rightly observe above, the paper’s conclusions rely on
the circular argument that variations of O2 sources and sinks cannot have been responsible for the rise in atmospheric O2 because it is assumed the sources and sinks are – and for at least 800,000 years have been – in balance (an assumption is not fact and is not evidence)
the logical error of assuming there is only one possible cause for the rise in atmospheric O2 because they cannot imagine a different cause.

Is this paper really what now passes as being scientific information?


Joao Martins
Reply to  Richard S Courtney
December 21, 2021 7:21 am

I ask the same question. Seems that peer-review is long gone and dead.

Reply to  Joao Martins
December 21, 2021 12:33 pm

Critical thinking seems to be out of fashion, for sure.

Joao Martins
December 21, 2021 3:14 am

We know atmospheric oxygen levels began declining

Don’t you feel that shortness of breath, Joe? That incresing difficulty in breathing? You know, now there is already less 0.2 % oxygen in the air than 800 000 years ago!

Zig Zag Wanderer
Reply to  Joao Martins
December 21, 2021 3:56 am

0.2% less oxygen. 0.01% more CO2.

I’m already SUFFOCATING!

Rick W Kargaard
Reply to  Joao Martins
December 21, 2021 9:30 am

I wasn’t breathing too well 800,000 years ago either. I think we are adapted to a fairly wide range of oxygen levels or it would be difficult to live at higher elevations.

Reply to  Joao Martins
December 21, 2021 2:42 pm

It’s making covid worse!

December 21, 2021 3:24 am

So, volcanism, fire etc couldn’t have played a part.

Joao Martins
Reply to  fretslider
December 21, 2021 7:23 am

No. Humans did. They are breathing too much.

Rick W Kargaard
Reply to  Joao Martins
December 21, 2021 9:32 am

Maybe breeding too much

Clyde Spencer
Reply to  Rick W Kargaard
December 21, 2021 11:27 am

Yes, it is the heavy breathing that creates the problem!

December 21, 2021 3:53 am

When did fungi become prevalent enough to put a stop to coal seams being laid down? There might be a clue there.

Loren Wilson
December 21, 2021 5:22 am

As pointed out in this thread already, it is much more likely that the drop in oxygen was caused by reduced photosynthesis due to colder temperatures and less plant cover. The amount of algae and phytoplankton could have been lower in the oceans due to cooler water overall and less area exposed to sunlight. Did they account for these significant variables? If not, they fail Feynman’s process for developing a hypothesis.

Joao Martins
Reply to  Loren Wilson
December 21, 2021 7:24 am

Excellent point!

December 21, 2021 5:44 am

I don’t know, something sounds screwy here. Glacial melting would release oxygen bound up in the ice, right? So glaciers getting smaller would not reduce O2 it would increase it no matter what effect newly exposed ground would have. I mean come on, man, 0.2% decrease over 800,000 years is really significant? Would not a reduction in overall volume of oxygen not be more likely from changes in plant life during that period? Fewer plants, less oxygen. This just doesn’t pass the smell test.

Clyde Spencer
Reply to  2hotel9
December 21, 2021 11:30 am

As usual, talking about small numbers (i.e. -0.2%) without citing the range of uncertainty for the measurements.

December 21, 2021 6:17 am

I call bullshit on the claim that the biosphere does not contribute to oxygen concentrations in the atmosphere. The only significant source of oxygen in the atmosphere has always been the biosphere, specifically green plants that absorb sunlight and CO2 and produce oxygen.

So naturally, when 2 km thick icesheets cover 1/3 of all the land mass where all green plants live, the rate of oxygen generation is going to decrease by a similar proportion.

Coach Springer
December 21, 2021 6:20 am

So, according to this, we need to stay warm. Even if true, I doubt that burning coal for all our energy would do the job.

Nick Schroeder
December 21, 2021 7:07 am

So, this post is prefaced with “Peer Reviewed Publication.”
Is that, like, ya know, the Good Housekeeping seal of scientific approval?
Will this “appeal to authority” now be the new normal?

A PhD is no guarantee that the holder cannot be wrong, make mistakes or deny and cover-up his errors.
Same for a clique/cabal/coalition of PhD good-old-boys/girls.

What happened to “Take no one’s word for it.”

Tom Abbott
Reply to  Nick Schroeder
December 21, 2021 8:03 am

“What happened to “Take no one’s word for it.”

That’s only done here at WUWT now. The professional Scientific Associations have gone over to the Climate Change Darkside.

December 21, 2021 8:37 am

Does that mean we need to melt the glaciers in order to save the atmosphere?

December 21, 2021 9:27 am

CAUTION: Ice core Samples are very much like calculating the size of migrating bird flocks over time, based on the amount of bird dung collected by vertical soil probes in assumed undisturbed ground. In other words, the claimed accuracy simply isn’t there and is fraught with confirmation bias.

In the case of ice cores, we are assuming atmospheric isotopes have been deposited in the gas bubbles at a known rate comparable to 1950 to present, and modifications thereof. There is a very good chance that something other than global atmospheric temperature causes those lines to track each other in various locations, especially since we are calculating temperature FROM those isotope lines. Much work has gone into it, but the error bars in gas bubble analysis are pretty wide when you look at more than just the isotope analysis and start looking at how much ice you had to melt to get a gas sample.

Last edited 1 year ago by DMacKenzie
Rick W Kargaard
December 21, 2021 9:52 am

As usual, I would like to know the measurement technique for determining oxygen output versus absorption of the biosphere. Sounds as sketchy as attribution science.

December 21, 2021 11:23 am

It’s highly likely that there’s a “hide the incline” hiding in this data. That is – that the recent sharp anthropogenic uptick in CO2 – via the resultant increase in global photosynthesis – will be causing oxygen concentration in the air to reverse its late Pleistocene decline and climb upward.

Yes I know oxygen comes from water (via photosynthesis) not CO2. But CO2 makes more photosynthesis. So CO2 does kind of make more oxygen.

This happened before – when plant growth and extent and thus the amount of photosynthesis increased globally during the carboniferous, atmospheric oxygen increased. Remember those monster dragonflies (Meganeura) with one yard (meter) wingspans? More oxygen means bigger insects.

So the current epoch should not be called merely the “Anthropocene”; it would be better to call it the “Anthropocarboniferous”.

December 21, 2021 4:57 pm

“The ice age Earth is in today began about 2.7 million years ago.”

Utterly and totally negating the 146 million year cycle, I’ll give an F for FAIL.

Not to the student. To hir professor.


Clyde Spencer
December 21, 2021 5:56 pm

David Middleton previously covered research published in PNAS that claimed that glaciers ground up rock containing pyrite, leading to more rapid oxidation of the pyrite:

Basically, black shales (and coal) typically have significant quantities of pyrite and marcasite (both iron sulfides), which when finely ground up will oxidize quickly, producing iron sulfate, and in so doing remove oxygen from the atmosphere. That is one mechanism that can account for the decline in oxygen, at least in part. The oxidation of the iron sulfides produce what is commonly called ‘acid mine-drainage.’ When it encounters limestone it will produce CO2. I don’t think that any of the published Carbon Cycle studies take account of the CO2 released by acidic rain or sulfuric acid produced by natural sulfide oxidation and assisted by anaerobic bacteria.

Acidithiobacillus spp.

Acidithiobacillus are chemolithoautrophics, Gram-negative road-shaped bacteria, using energy from the oxidation of iron and sulfur containing minerals for growth. They are able to live at extremely low pH (pH 1–2) and fixes both carbon and nitrogen from the atmosphere. It solubilizes copper and other metals from rocks and plays an important role in nutrient and metal biogeochemical cycling in acid environments. Acidithiobacillus ferrooxidans is abundant in natural environments associated with pyritic ore bodies, coal deposits, and their acidified drainages. It obtain [sic] energy by the oxidation of reduced sulfur compounds and it can also reduce ferric ion and elemental sulfur, thus promoting the recycling of iron and sulfur compounds under anaerobic conditions. It can also fix CO2 and nitrogen and be a primary producer of carbon and nitrogen in acidic environments.

December 21, 2021 6:02 pm

The airplane is the background of the photo is from Ken Borek Air (KBA) of Calgary. In June 2016 KBA flew the most difficult and perilous flight ever undertaken to the South Pole in the coldest depths of the Antarctic winter, to rescue two critically-ill scientists and return them to North America. Calgary crew: Pilot Wally Dobchuk, co-pilot Sebastien Trudel, maintenance engineer Mike McCrae.
An extremely high-risk mission, accomplished with precision. No “safe spaces”.  🙂

Calgary crews honoured for plucking sick workers from South Pole amid blizzards and –60 C temperatures
David Bell · CBC News · Posted: Mar 29, 2017
Two crews from the Calgary-based Kenn Borek Air received a prestigious award Wednesday night in Washington, D.C., after a dangerous rescue from the South Pole in 2016. (National Science Foundation)
The Canadian flight crews who rescued two sick workers from the South Pole in an “audacious” operation amid blizzards and –60 C temperatures have been honoured with a Smithsonian National Air and Space Museum Trophy for outstanding achievement.
In June 2016, the Calgary-based Kenn Borek Air team flew two Twin Otter aircraft from Calgary to Chile, a journey of 12,500 km in 45 hours. After a delay due to bad weather, they then made the perilous 1,600-km journey to Rothera, Antarctica.
One plane then travelled another 2,400 kilometres to the U.S. National Science Foundation’s Amundsen-Scott Research station at the South Pole to pick up two people who needed to be taken to hospital.

On the 1,500-mile (2,414-kilometer) trip to pick up two sick patients, the crew battled iced-up wings, an overloaded cabin, and icebergs blocking the runway—and still arrived in one piece.
By Douglas Fox
Published July 8, 2016

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