Continued CO2 Emissions Will Impair Cognition

From Cires

Rising CO2 causes more than a climate crisis—it may directly harm our ability to think

Monday, April 20, 2020

As the 21st century progresses, rising atmospheric carbon dioxide (CO2) concentrations will cause urban and indoor levels of the gas to increase, and that may significantly reduce our basic decision-making ability and complex strategic thinking, according to a new CU Boulder-led study. By the end of the century, people could be exposed to indoor CO2 levels up to 1400 parts per million—more than three times today’s outdoor levels and well beyond what humans have ever experienced.

“It’s amazing how high CO2 levels get in enclosed spaces,” said Kris Karnauskas, CIRES Fellow, associate professor at CU Boulder and lead author of the new study published today in the AGU journal GeoHealth. “It affects everybody—from little kids packed into classrooms to scientists, business people and decision makers to regular folks in their houses and apartments.” 

Shelly Miller, professor in CU Boulder’s school of engineering and coauthor adds that “building ventilation typically modulates CO2 levels in buildings, but there are situations when there are too many people and not enough fresh air to dilute the CO2.” CO2 can also build up in poorly ventilated spaces over longer periods of time, such as overnight while sleeping in bedrooms, she said.

Put simply, when we breathe air with high CO2 levels, the CO2 levels in our blood rise, reducing the amount of oxygen that reaches our brains. Studies show that this can increase sleepiness and anxiety, and impair cognitive function. 

We all know the feeling: Sit too long in a stuffy, crowded lecture hall or conference room and many of us begin to feel drowsy or dull. In general, CO2 concentrations are higher indoors than outdoors, the authors wrote. And outdoor CO2 in urban areas is higher than in pristine locations. The CO2 concentrations in buildings are a result of both the gas that is otherwise in equilibrium with the outdoors, and also the CO2 generated by building occupants as they exhale. 

Atmospheric CO2 levels have been rising since the Industrial Revolution, reaching a 414 ppm peak at NOAA’s Mauna Loa Observatory in Hawaii in 2019. In the ongoing scenario in which people on Earth do not reduce greenhouse gas emissions, the Intergovernmental Panel on Climate Change predicts outdoor CO2 levels could climb to 930 ppm by 2100. And urban areas typically have around 100 ppm CO2 higher than this background.

Karnauskas and his colleagues developed a comprehensive approach that considers predicted future outdoor CO2 concentrations and the impact of localized urban emissions, a model of the relationship between indoor and outdoor CO2 levels and the impact on human cognition. They found that if the outdoor CO2 concentrations do rise to 930 ppm, that would nudge the indoor concentrations to a harmful level of 1400 ppm. 

“At this level, some studies have demonstrated compelling evidence for significant cognitive impairment,” said Anna Schapiro, assistant professor of psychology at the University of Pennsylvania and a coauthor on the study. “Though the literature contains some conflicting findings and much more research is needed, it appears that high level cognitive domains like decision-making and planning are especially susceptible to increasing CO2 concentrations.”

In fact, at 1400 ppm, CO2 concentrations may cut our basic decision-making ability by 25 percent, and complex strategic thinking by around 50 percent, the authors found.

Full article here

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April 24, 2020 2:20 am

Submarines average 3-4 thousand ppm and can run over 10,000 ppm. If one loses half ones complex strategic thinking at 1,500 ppm, where does that leave the submariners?/

Jay Willis
Reply to  MikeP
April 24, 2020 2:35 am


Leo Smith
Reply to  Jay Willis
April 24, 2020 3:12 am


Reply to  Leo Smith
April 24, 2020 5:22 am

I am sorry, but that reply was all wet.

Reply to  shrnfr
April 24, 2020 5:34 am

It may be a little late to notice but apparently 414 ppmv severely impairs the cognitive processes of a large proportion of the western world already.

Oddly this seems to affect some sectors of the population more than others. There seems to be a strong correlation with WOKE. The biochemical pathway for this effect is illusive , more money is needed to find the cause of this important societal problem.

Tom Abbott
Reply to  shrnfr
April 24, 2020 7:18 am

“It may be a little late to notice but apparently 414 ppmv severely impairs the cognitive processes of a large proportion of the western world already.”

I don’t think it is the ppm level per se that is driving the alamists crazy, it is their delusional fear of CO2 that causes them to be unable to think straight, exaserbated, of course, by the CAGW Charlatans who have been lying about the situation for years.

Skeptics aren’t having any mental problems at 414ppm, at least none that are caused by CO2. 🙂

Reply to  shrnfr
April 24, 2020 12:24 pm

Actually, I think it is the phytosterols in avocados which open the biochemical pathways for CO2 to impair inter-neuronal activity, but I need more money to continue this important work.

Reply to  shrnfr
April 25, 2020 3:38 pm

What’s REALLY amazing is that non of these idiots even realize that human beings only contribute 3% of the CO2 in the atmosphere. The rest is all “natural” and we have zero control over it. The plants that comprise our food chain. and other plants like trees etc, take most of it out each year, so we will never put too much into the equation. More CO2 creates more plant growth which consumes more CO2 and makes more food and plant growth. I realize this is too simple for the “educated idiots” to comprehend, but luckily that doesn’t change the reality.

Reply to  MikeP
April 24, 2020 2:49 am

Yep, here we go again

“Data collected on nine nuclear-powered ballistic missile submarines indicate an average CO2 concentration of 3,500 ppm with a range of 0-10,600 ppm”

Rich Davis
Reply to  mwhite
April 24, 2020 3:46 am

Also, at the current/historical 2ppm per year it would take over 250 years to reach the level that they claim it will reach in 80 years.

Tom Abbott
Reply to  Rich Davis
April 24, 2020 7:20 am

Yeah, I think that 900ppm figure is based on humans burning all the available fossil fuels on Earth in just a few short years.

That shows you how sloppy this study is, when they can’t even get that figure correct.

Reply to  Tom Abbott
April 24, 2020 9:53 am

It utter claptrap to say that one gets drowsy in lectures die to CO2. If you are warm and cozy from all the warm bodies and the subject matter is a drone of boredom, it is perfectly natural for your mind to want to do something else, and even sleep is more productive at that point. A type of reactive inhibition.

As CO2 partitions 50 to 1 into water, we would have to add 50 times as much CO2 as to simply double the atmospheric CO2. There is simply not enough carbon for us to burn,. We might get a 20% rise, but the oceans would fight us overstep of the way, the higher activities of plants fighting us as well.

Reply to  Tom Abbott
April 24, 2020 12:18 pm

True indeed Charles H at 9:53am.

Fortunately for me, sleeping through quantum mechanics lectures steered me towards organic chemistry. As that old saying goes – there but for the grace of God go I.

Reply to  Rich Davis
April 24, 2020 12:20 pm

Sorry, Rich, but the article is not talking about outdoor CO2 levels, but indoor levels. I think it possible that such levels could be achieved in a closed room with poor circulation.

I do have a problem with the statement “We all know the feeling: Sit too long in a stuffy, crowded lecture hall or conference room and many of us begin to feel drowsy or dull.” Warm air alone could account for those reactions. Combine that warmth with a dull speaker or topic, maybe little sleep the night before, and most anyone will nod off.

Rich Davis
Reply to  ex-KaliforniaKook
April 24, 2020 6:32 pm

Please go back and read more carefully.

the Intergovernmental Panel on Climate Change predicts outdoor CO2 levels could climb to 930 ppm by 2100.

Yes, they also hyperventilated about indoor CO2, but the driving force for indoor levels supposedly rising dangerously was the assumption that outdoor CO2 would be 930 ppm in the next 80 years.

CO2 has been rising at 2 ppm/yr, and is around 415 ppm at the moment. In order to reach 930 ppm within 80 years, it must average 6.4 ppm/yr. (3.2x the current rate). K If that average rate is achieved by a linear acceleration that reaches the average 6.4 ppm/ year by the midpoint 2060, that implies 8.4 ppm/yr in 2100. That is 4.2x the current rate, and would seem to be physically impossible. That would require burning far more than four times current consumption of fossil fuel because as atmospheric CO2 gets further and further out of equilibrium with partial pressure of CO2 in the ocean, the driving force increases for the oceans to absorb more CO2.

Reply to  mwhite
April 24, 2020 7:15 am

0 ppm?

Gordon Dressler
Reply to  mwhite
April 24, 2020 10:10 am

. . . and some of those submariners are responsible for missiles that could start WWIII, knocking humanity back at least a couple of thousand years.

Also, let’s not forget our beloved space programs . . . NASA has set the maximum allowable 24-hour average CO2 on board the manned International Space Station at 5,250 ppm (4.0 mmHg). NASA used to have an even higher maximum such limit of 7,000 ppm on the manned ISS.

US astronaut Christina Koch logged 328 consecutive days aboard ISS and US astronaut Scott Kelly spent the current record of 340 consecutive days aboard ISS. Last I heard, they were both doing just fine.

I conclude that both US DoD and NASA each know a helluva lot more about the effects of continuous elevated-CO2 levels on human physiology and brain function than does Kris Karnauskas, CIRES Fellow and associate professor at CU Boulder.

Reply to  Gordon Dressler
April 24, 2020 1:40 pm

Don’t forget greenhouses, which typically have CO2 levels of 1,200 ppm. Should OSHA step in?

Reply to  MikeP
April 24, 2020 3:03 am

Is that why our school kids are all stupid? Class rooms have anywhere between 800 and 1200 ppm of CO2 depending on the time of the day and how enclosed they are!

Reply to  John Grosse
April 24, 2020 3:21 am

We’ll soon know. All the kids are at home sitting in front of their monitors doing schoolwork. Grandson got straight A’s.

Bryan A
Reply to  pochas94
April 24, 2020 5:15 am

Perhaps that’s why they’re called
Bored Room Meetings

Reply to  John Grosse
April 24, 2020 6:09 am

A high proportion of mouth breathers.

Reply to  MikeP
April 24, 2020 9:31 am
James Beaver
Reply to  MikeP
April 24, 2020 4:38 pm

I can confirm your observation. I was an Atmosphere Control Technician (among other duties) on a U.S. SSN.
When we get to 8,000 PPM, I’ll plant more trees.

Aaron W Edwards
Reply to  MikeP
April 26, 2020 12:30 pm

My thought exactly. I wonder why Charles Rotter does not know this?

Kiwi Gary
April 24, 2020 2:32 am

Please explain why submariners are not endangered by much higher levels during their 3 months submerged. I have seen reports of nuclear submarine atmospheres as high as 8000 ppmv. During WW2, some submarines were forced by hunters to stay sumerged for so long that even matches wouldn’t light and doctors reckoned that the crew should have not survived that level of carbon-dioxide. Not only did they survive, but remained capable of operating their machinery. No computers those days.

Reply to  Kiwi Gary
April 24, 2020 3:43 am

Exhaled breath is typically 40000ppm to 50000ppm, more if you are working hard.
Breathing makes you dumb, as we all know.

Ed MacAulay
Reply to  mothcatcher
April 24, 2020 4:29 am

At that level for exhaled air, could anyone doing mouth to mouth rescue breathing be charged with murder when the victim dies?

Reply to  Ed MacAulay
April 25, 2020 1:15 am

In exhaled breath there is 16% oxygen, which is adequate to maintain life even with the high concentration of carbon dioxide.
For some people with COPD they need higher concentrations of circulating carbon dioxide to continue breathing, high levels of external oxygen (above 28%) could kill them.
If someone hyperventilates then they are given a paper bag to rebreathe into to restore carbon dioxide levels in the blood.
The human physiology developed from ancestors that lived in low oxygen environments of around 4%, which some cells still require and would die if exposed to higher concentrations. The blood stream acts as a reservoir.
There’s a book printed by Oxford University press called “Oxygen” which explains some of this.

Reply to  mothcatcher
April 24, 2020 5:36 am

If you are working hard you are probably dumb already. Smart people sit back and make others do all the hard work 😉

Reply to  Greg
April 24, 2020 5:49 am

is that why trump is so dumb? he is working too hard. suggesting getting bleach into the body ou uv light into the lungs to kill covid-19 virus. (does he realise that the virus is in all parts of the body so you would need to dissect a patient into a single layer then expose to UV or bleach. Trick is the re-assembly may require time, then waiting for lightening to re- energise the corpse may be too long to be effective.!!!

Reply to  ghalfrunt
April 24, 2020 9:04 am

It really is sad how haters have to drag the object of their hate into every conversation.

Would you care to provide transcripts of everything you have ever said so that I can go thought them and point out all the stupid things you have said over the years?
On the other hand, we have plenty of examples from the things you have written here.

Michael Jankowski
Reply to  ghalfrunt
April 24, 2020 10:02 am

ghalfrunt I think you’d make a great test subject.

Reply to  ghalfrunt
April 24, 2020 12:25 pm

Here we go again. Greetings from the orangemanbadosphere

At least the guy’s purportedly less white than the old white guys we’re supposed to hate, purportedly. You know, like the last two “lefties” on the phony-leftie orangemanbad ticket.

Reply to  mothcatcher
April 25, 2020 12:08 am

When doing a course on confined spaces, or the like, I was told that the test instrument was set to detect CO2 at levels of 120 000 ppm, = 12%, and hazardous to life. I found that by holding my breath as long as possible, and then breathing into the detector, I could set off the alarm. Did that indicate I was dead? Don’t think so as I am still surviving about 25 years later.

Sweet Old Bob
Reply to  Kiwi Gary
April 24, 2020 4:28 pm

We were over 20,000 ppm for several days .

Nobody died…. 😉


April 24, 2020 2:32 am

“In fact, at 1400 ppm, CO2 concentrations may cut our basic decision-making ability by 25 percent, and complex strategic thinking by around 50 percent, the authors found.”

I would say 100% cognitive loss even at 400ppm for those clowns.

Robert W. Turner
Reply to  Petit_Barde
April 24, 2020 7:00 am

Indeed, we have ample evidence that the release of CO2 has already diminished the cognitive abilities of those that are concerned about it – I’m going to say a 40% reduction in decision making ability because that is something measurable. So with your 100% estimate and my 40% estimate, that is an estimated 70% loss of cognition on average among those that are concerned about man made climate change – climate science is fun!

April 24, 2020 2:34 am

“Rising CO2 causes more than a climate crisis—it may directly harm our ability to think”

It already has, apparently.

I will add this study to my collection of such studies with thanks to wuwt

Reply to  chaamjamal
April 24, 2020 6:12 am

You deserve some thanks, too, chaamjamal.

Nick Werner
Reply to  chaamjamal
April 24, 2020 9:13 am

Don’t be too quick to dismiss this study’s conclusion; the researchers can point to their own work as proof.

Moderately Cross of East Anglia
April 24, 2020 2:36 am

Too late, judging from some of the nonsense the climate alarmists come out with!

Walt D.
Reply to  Moderately Cross of East Anglia
April 24, 2020 4:41 am


April 24, 2020 2:39 am

There could be something in this. To judge by the decline of intelligence in the Media, politics and the general population, the rising CO2 levels may be already having an effect.

Steve Borodin
Reply to  nicholas tesdorf
April 24, 2020 4:44 am

Its 50,000 ppm at the BBC.

April 24, 2020 2:45 am

Do these professors really live in this world in this world?
Adequate ventilation with extractor fans in summer and heat pumps in winter and there will never be a problem.
There was a saying when I was at school in the 1950s that some of these experts learn more and more about less and less and the then know everything about nothing .
Since then CO2 has appeared as the greatest supposed threat to mankind and any scientific paper written and published about CO2 is well funded even rubbish like this .
I remember eating out at a restaurant in Wellington many years ago with a group and we carried on close to midnight
The manager and staff were to polite to ask us to leave so they opened up all the windows and windy Wellington soon froze us on our way .

Reply to  Gwan
April 24, 2020 6:56 am

These experts are learning more and more about less and less until they know
everything about nothing.

April 24, 2020 2:48 am

This is going to be a fun thread to read when it fills up some more. So far with only 7 comments, it’s made me smile and I can use a lot more of that. I’ll have to come back a couple more times.

Stay safe and healthy, all.


April 24, 2020 2:51 am

These studies also indicated that oxygen depletion in enclosed environments had more effect than increases in CO2. But that doesn’t make good headlines.

Oxygen depletion caused the Dyatlov event in Russia.

Reply to  Prjindigo
April 24, 2020 7:23 am

After 50 years of research, nobody knows what caused the Dyatlov event. But whatever it was, oxygen depletion could not have been it. 9 hikers in a canvas tent, they weren’t even using their stove.

Ron Long
April 24, 2020 2:56 am

“CU Boulder” study about CO2? For sure this was a Coors Beer experiment that got off the tracks. Great comments above, RE Submarines.

Reply to  Ron Long
April 24, 2020 6:36 am

AHA! Ever drive in Boulder, CO? Half the people on the road are suffering from severe hypoxia. That’s what this study is really about, boroshitu and and hypoxia.

How is this supposed to work? The CO2 outside goes up to 900 ppm, and then leaks inside our homes and work spaces, which are already 1000 to 1200 ppm, and make us stupid? Who could fail to grasp the madness of that notion? Although, TBF, OTOH, there’s strong evidence that some people in Boulder have already been affected.

“Yes, there will be rabbits, Lennie.”

Eoin mc
April 24, 2020 2:57 am

This latest alarmist confection presumes already-high levels of cognitive ability. My experience over forty years of adulthood is that the vast majority of people, including those in the fields of climate-related earth studies in academe, are already embedded and chronically trapped in their own confirmation biased bubbles. Any marginal increases in indoor carbon dioxide can hardly make alarmists any more entrenched in their myopia.

Reply to  Eoin mc
April 24, 2020 6:40 am

It’s not myopia, it’s proctocraniosis. Very high concentrations of CO2 and deadly H2S present.

April 24, 2020 2:58 am

The date on this post is wrong…surely it was published on April 1.

April 24, 2020 3:04 am

More utter piffle from so called researchers. Grab the grant money and make-up more ridiculous nonsense.
CO2’s makes plants grow and judging from this so called research by Kris Karnauskas, CIRES Fellow, associate professor at CU Boulder and lead author of the new study published today in the AGU journal, vegetable matter is in his brain.

Carl Friis-Hansen
April 24, 2020 3:17 am

Not all scientists agree!!!

Thus, even at values more than 36 times the present CO2 concentration of the atmosphere (15,000 ppm) Rodeheffer et al. were “unable to detect any decrements in decision-making performance.”

A quote from:

Reply to  Carl Friis-Hansen
April 24, 2020 9:23 am


April 24, 2020 3:36 am

Put simply, open a window. Ignore the PPM numbers game.

Reply to  RStabb
April 24, 2020 4:09 am

Already to much CO2 in the house and thus to low cognition level to achieve such a complexe task.

Reply to  RStabb
April 24, 2020 5:00 am

RStabb: “Put simply, open a window. Ignore the PPM numbers game.”

But I’d advise against that on submarines.

Or screen doors. No screen doors. They’ll have to work out something else.

Reply to  H.R.
April 24, 2020 5:52 am


Point taken. It’s never easy.

April 24, 2020 3:37 am

To be a[n associate] professor these days requires an incredibly dim mind.

Put simply, it’s another load of complete, total and utter tosh.

It’s amazing how high CO2 levels get in enclosed spaces,”

It’s amazing how many enclosed spaces have windows and doors.

Walt D.
Reply to  fretslider
April 24, 2020 4:44 am

To repeat the old cliche:
BS = Bull Sh*t
MS = More Sh*t
PhD = Piled higher and deeper.

Rich Davis
Reply to  fretslider
April 24, 2020 5:06 am

That may not be a fair assumption. They may be quite clever. What is required is at least the appearance of orthodox green piety. If your job depends on appearing to be utterly convinced of whacked green dogmas, and no funding goes to heretical research, it’s likely that you will delude yourself into accepting the green dogmas on faith and never think dangerous thoughts.

You have to admit, there is no end to their creativity. CO2, is there nothing it cannot do?

Reply to  fretslider
April 24, 2020 6:54 am

“It’s amazing how many enclosed spaces have windows and doors.”

Some don’t. Stay out of them.

Steven Fraser
Reply to  jorgekafkazar
April 24, 2020 7:43 am

Good advice for living above the grass.

Coeur de Lion
April 24, 2020 3:41 am

My chum used to drive a ‘bomber’ as they called them and still speaks four languages. Btw I think we should always speak of CO2 in molecules per ten thousand not ppm. So since 1850 CO2 has risen from just under three to just over four molecules per ten thousand AND HAS MELTED THE ARCTIC ICE CAP!

Reply to  Coeur de Lion
April 24, 2020 7:36 pm

It’s been struggling lately. Beating down on ice at 20 below C or F just ain’t what it used to be.

Come on carbon, up your game.

Flight Level
April 24, 2020 3:48 am

Hypoxia, the new atmospheric CO2 scare? Might work on those already affected by acute oligophrenia.

Jeff Id
April 24, 2020 3:53 am

The question is, will the believer crowd notice.

April 24, 2020 4:02 am

930 ppm is 500 ppm higher than at present. At an annual increase of 2ppm, that is 250 years.
Consider that 1 year ago the global economy was thriving , as were most of the worlds inhabitants , everyone cheerful and optimistic , making plans for careers and holidays, and now there are millions of excess deaths, the economy of most nations has been wrecked and milions in Europe and US have lost jobs , businesses , possibly also their homes. Did any of us see that coming?
How can we be certain of what awaits us in the next 250 years. A rise in internal CO2 is likely to be the least of the world’s worries.
I suppose most of these nonsense papers were made up before the Wuhan apocalypse struck. There may be fewer of them in the future with universities closed or operating online. Difficult see how practical engineering and science lab- based teaching and experimenting can be done with just a server and laptop.
Some universities may never re- open . The well rated University of Manchester (UK) is missing £270 million pounds in the next financial year according to the BBC and other Russell group (ie top rated) universities are also in trouble. There may not be the funds for silly stuff when a country is bleeding out , financially.

Jeff Id
Reply to  mikewaite
April 24, 2020 5:56 am

150 years ago, we were riding horses. I wonder if anything might change 150 years from now.
These folks are silly.

Robert W. Turner
Reply to  mikewaite
April 24, 2020 7:03 am

When I read that, my first thought was finally someone is being bullish on the economy!

Rich Davis
April 24, 2020 4:03 am

Shocked to see that this doesn’t come to us via our EurekAlert! friends. “How can this be?”, I wondered. Is my EurekAlert! detector out of calibration?

It turns out that my EurekAlert! bs meter is still working just fine:

Carl Friis-Hansen
April 24, 2020 4:04 am

Carbon dioxide levels measured in-flight in the aircraft cabin ranged between 0.04% or 400 ppm and 0.1% or 1000 ppm to date in our studies and were measured at close to 0.5% or 5,000 ppm in earlier studies.

As indicated at CO2 HEALTH EFFECTS, occupants are unlikely to be affected or to notice CO2 levels under 2% or 20,000 ppm – a far higher number than in-flight aircraft cabin carbon dioxide levels.


Anyway, what does it matter?
The Greens top bras does not want to save mankind, only planet Earth – Earth likes the higher CO₂ level – so the CU Boulder-led study is just a substitute for studying something useful, which may demand way more diligence and intelligence (and a few DuckDuckGos).

April 24, 2020 4:05 am

Since global progressives/left overwhelmingly live in large, densely populated cities, this phenomenon would be a plus.

April 24, 2020 4:07 am

Finally! A climate change study where the study itself is the proof of the thesis.

Reply to  BallBounces
April 24, 2020 6:27 am

Joachim Lang
April 24, 2020 4:42 am
Table 7-2:
Time 1000h
Limit 0.5% (New value based on avoiding any risk of mild headache.)
[0.5% = 5000ppm]
Law’s paper is the first serious look into the subject, and her team’s recommendation is to go even lower, to 2.5 mm Hg. They found that “for each 1-mm Hg increase in CO2, the odds of a crew member reporting a headache almost doubled.” Their recommended level of 2.5 mm would, according to the paper, “keep the risk of headache to below 1%, a standard threshold used in toxicology and aerospace medicine.” [2.5mm Hg = 333Pa this is equivalent to 5050ppm]

The air in the International Space Station has a concentration of 5000 ppm.
NASA apparently tries to cognitively impair the astronauts.

Acute Exposure to Low-to-Moderate Carbon Dioxide Levels and Submariner Decision Making
“RESULTS: There were no significant differences for any of the nine SMS measures of decision making between the CO2 exposure conditions.”

Farmer Ch E retired
April 24, 2020 4:50 am

Has anyone shared this study with the NASA or greenhouse workers? The ISS environment has 7 to 17 times the CO2 partial pressure as atmospheric (reported in mm Hg). Greenhouse CO2 concentrations may reach 1500 ppm CO2, a mere 3.5 times atmospheric. I’d say the astronauts are in serious trouble. #bringastronautshome

Hans Erren
April 24, 2020 5:08 am

I think somebody forgot to tell the researcher that the RCP8.5 scenario should no longer be used as a busines-as-usual case!

April 24, 2020 5:18 am

Post on from 2012.

Jim Gorman
April 24, 2020 5:20 am

Ask yourself that at Standard Temperature and Pressure (STP) if you increase CO2 ppm what has to go? O2 maybe? Could that cause cognitive problems?

April 24, 2020 5:20 am

Must have been what killed off the dinosaurs…..a significant reduction in basic decision-making ability and complex strategic thinking

April 24, 2020 5:28 am

Noted in passing is the fact that “oxygen concentrators” used to supply oxygen medically to patients are really “nitrogen removers”. They increase the oxygen in the exhaust gasses by removing the nitrogen in the input gasses. As a result, the concentration of CO2, etc. increases by a factor of over 4 in the stream used to give to the patient. The output stream is thus about 90% O2, 5% Ar, 2% CO2, and so forth. The patients do quite well on it.

The authors of that article would do well to stop huffing the gasses from club soda.

Reply to  shrnfr
April 24, 2020 6:47 am

That’s an interesting thought.

I did a quick search on pressure swing absorption oxygen concentrators and didn’t find any technology that is used to remove CO2, H2O or radon for that matter. It could be that because CO2 and H2O are absorbed to a greater degree than N2 that the timing of the swings yields about the same concentration in the feed and output.

Reply to  shrnfr
April 24, 2020 1:34 pm

That increase in CO2 will tend to strengthen the breathing reflex slightly, which might be considered an extra bonus effect.

However increasing CO2 by a factor 4 only yields 0.16 % (=1600 ppm), not 2 %

April 24, 2020 5:29 am

There’s been a lot of work in classroom CO2 levels. example

IMHO, concentrating on CO2 is barking up the wrong tree. Heat and humidity have a much bigger effect. link The other thing is the various substances emitted by human beings.

Occupants of aircraft have reported an array of symptoms related to general discomfort and irritation. Volatile organic compounds (VOCs) have been suggested to contribute to the reported symptoms. VOCs are from products used, bioeffluents from people and ozone reaction products. link

The stuffy brain-deadening atmosphere in a poorly ventilated classroom or aircraft cabin has a lot less to do with CO2 than with other factors.

Reply to  commieBob
April 24, 2020 6:33 am

Farts ?

Reply to  Petit_Barde
April 24, 2020 6:39 am
William F Ballinger
April 24, 2020 6:03 am

Sounds like some people need to add some houseplants to the mix. Best looking house plants I have seen are always in offices or classrooms. They love the higher CO2 and provide lots of nice O2 as a thank you, as well as providing free air filtration. Bet most offices of climate wackos lack this simple fix, hence their cognitive distress.

April 24, 2020 6:47 am

With exhaling at 40,000 ppm, what does wearing a mask do to what you inhale? I’ll wear the mask against Covid 19 anyway.

April 24, 2020 7:02 am

Sitting in a stuffy lecture hall, one often falls asleep. This is not because of the increase in CO2, but because the Oxygen is being used up!

CO2 is actually a stimulant!

If you start with the wrong assumptions, you will end up with the wrong conclusions!

Michael Ozanne
April 24, 2020 7:12 am

These authors appear to have followed the Oozlum bird to it’s final destination….

Steven Fraser
Reply to  Michael Ozanne
April 24, 2020 7:46 am

… Up the hill somewhere, now resident on one of the Flatirons.

Michael Ozanne
Reply to  Steven Fraser
April 24, 2020 8:14 am

It’s more fundamental than that…..

April 24, 2020 7:12 am

Outside CO2 levels rising from 280ppm to a bit under 500ppm (maybe) is going to cause indoor CO2 levels to go from 500ppm to over 1500ppm????

I’m calling BS on that claim.

The only way indoor CO2 levels will rise that much is if we reduce the amount of air exchange from inside to outside drastically. And if that’s the case, the problem lies with the lack of air exchange, not the outside ambient CO2 levels.

All other things being equal, if outside CO2 goes up by 10ppm, then indoor CO2 goes up by the same amount. There is no multiplier in this equation.

Tim Gorman
April 24, 2020 7:13 am

Not a single author is a medical doctor trained in clinical studies. That is the first alert I saw.

What has peer review become today? Nothing more than a spell checking exercise? If I were to peer review this study I would have required the 2007 National Academy of Sciences study “Emergency and Continuous Exposure Guidance Levels for Selected Submarine Contaminants: Volume 1 (2007)” be referenced and the differences between it and this study be explained in detail.

The study states “Early experimental studies testing for the influence of relatively high concentrations of CO2 (5–8%) that might be present in confined and enclosed spaces like submarines found significant impacts on ability to respond to a stimulus (Harter 1967), reasoning (Sayers et al. 1987) and threat processing (Garner et al. 2011).”

The study does not mention at all the 2007 National Academy of Sciences study “Emergency and Continuous Exposure Guidance Levels for Selected Submarine Contaminants: Volume 1 (2007)” (see pages 6,7, and 8 for study particpants). The 2007 study states on Page 54: “A number of studies suggest that CO2 exposures in the range of 15,000-40,000 ppm do not impair neurobehavioral performance.” The 2007 study goes on to state on Page 54: “Thus, CO2 at 40,000 ppm for 2 weeks did not affect performance on multiple tests of cognitive function in physically fit young airmen, a population probably not unlike submariners”

The study states : “More moderately elevated concentrations (2.5%), such as those that may be present in passenger automobiles and aircraft, have been shown to impair visual perception (Yang et al. 1997) and ability to maneuver an aircraft (Allen et al. 2018)”

Yet the 2007 study states: “Based on the work of Storm and Giannetta (1974) and Glatte et al. (1967), a NOAEL of 30,000 ppm for general CNS effects could be proposed. However, the subcommittee considers the subtler, if less relevant, visual effects reported by Sun et al. (1996) and Yang et al. (1997) at 25,000 ppm to be a minimal LOAEL.”

(NOAEL – No Observed Adverse Effect Level, LOAFL – Lowest Observed Adverse Effect Level )
[NOAEL — Highest dose at which there was not an observed toxic or adverse effect.
LOAEL — Lowest dose at which there was an observed toxic or adverse effect.]

Somebody is misquoting the study by Yang and I sincerely doubt that it is the National Academy of Sciences who sponsored the 2007 study. The peer review process today would seem to be totally useless, at least when it comes to study of CO2!

Reply to  Tim Gorman
April 24, 2020 9:29 am


It’s fitting that you mention medical doctors right at the top of your (virtuoso) comment.

The Respiratory Medicine syllabus covers various equations doctors use routinely on the ward when solving problems like: what flow rate of supplemental oxygen does this patient need?

Many such equations include a term—a constant—that stands for the carbon-dioxide concentration of room air—like the air you inhale on a hospital ward.

Would anyone (other than Tim) like to take a stab at the value medical students are taught to ‘plug in’ for this term: the concentration of CO2 in room air?

Good guess. But no, it’s lower. Hmm. Keep going.


Still too high.

Bingo. Zero. For all medical intents and purposes, there is no carbon dioxide in the air you inhale inside a hospital.

But unless the upcoming negotiations in [insert tropical vacation spot] produce a solemn global vow of carbon austerity, scientists warn that that figure may be on track to double, or even TRIPLE, in our children’s lifetimes.

April 24, 2020 7:25 am

I read an article like this and, being an engineer, and assuming it’s a real problem (or a problem building owners want a solution), I think, “Let’s use ingenuity to solve the ventilation problem.” But I doubt the left cares about engineering solutions. Rather, it’s a reason to tighten the iron fist of regulation… for SCIENCE! For the CHILDREN! For our FUTURE! For -insert emotional thing here-!

April 24, 2020 7:27 am

As for so much other in Germany, there are regulations for CO2 too, so we have values for CO2, the MAK, max. concentration at workplaces (Maximale Arbeitsplatz Konzenztration) of 5000 ml/m³ (ppm) or 9100 mg m³ over 8 hours.

April 24, 2020 7:33 am

If there’s one thing the climate community can’t abide it’s misinformation.

They even have “Krusher Krews” whose sole function is to nip scientifically-illiterate urban myths in the bud.

And this one’s a doozy. How such crapscience survived the ruthless gauntlet of peer review is anyone’s guess, but editors’ heads are going to roll, that’s for sure.

Expect this crank meme to be added to Skeptical Science’s index mythorum debuncandorum any day now. I bet it won’t survive the weekend. They’re probably polishing the corrective article as we speak, double-checking that the fact-bomb they’re about to drop has 100% killpower first.

Reply to  Brad Keyes
April 24, 2020 9:31 am
Reply to  Scissor
April 25, 2020 3:13 am

All you’ve proven is that my comment was wrong about everything.

But that’s a strawman argument, because I have never claimed my comment was right.

Last time I checked, I wasn’t even a climate scientist. No serious person would get their views from a comment I wrote on some blog but couldn’t be bothered submitting for peer review.

So in fact your demolition of my claims is disingenuous, since it doesn’t stop the ice from melting, which it’s still doing despite your reply, which if it had been of any interest to scientists would have been in the peer reviewed literature, not on some blog.

Clearly, the climate science community doesn’t find your explosion of my argument, however fatal, noteworthy. So I hope you’ll forgive me if I don’t read it, preferring to get the discrediting of my views from the SCIENTISTS, not from the kind of person who comments at a site well-known for harboring diverse and inconsistent views.


Reply to  Brad Keyes
April 25, 2020 10:07 am

Let’s see if some rationality prevails. This article should not stand and is an embarrassment to CIRES and the Universities of Colorado and Pennsylvania.

April 24, 2020 7:51 am

Thus far it would seem alarmists are the main ones whose thinking has been compromised.

April 24, 2020 8:03 am

From the article:
In fact, at 1400 ppm, CO2 concentrations may cut our basic decision-making ability by 25 percent, and complex strategic thinking by around 50 percent, the authors found.

The room they were sitting in while working on that paper seems to have had some special components included, maybe Nitrous oxide (N2O), better known as laughing gas. (Nitrous oxide (N2O), also called dinitrogen monoxide, laughing gas, or nitrous, one of several oxides of nitrogen, a colourless gas with pleasant, sweetish odour and taste, which when inhaled produces insensibility to pain preceded by mild hysteria, sometimes laughter.)

Ian Coleman
April 24, 2020 8:21 am

So, is this for real? All I have to do to stop being so dumb is go outside? I dunno. As nearly as I can tell, I’m just as stupid outside as in, and it doesn’t rain in here. And I’ve got a TV set. And they make you wear pants when you go outside, and they always get so upset when I forget.

What I heard was, if you don’t have a build-up of carbon dioxide in your blood, you won’t have any stimulus to breathe. And I also heard that plants do something or other with carbon dioxide that is the exact opposite of what animals do, and this is a good thing. I don’t understand any of this, of course, because I’ve been breathing in too much carbon dioxide. And anyway, I don’t care.

Reply to  Ian Coleman
April 24, 2020 10:02 pm

That’s another strong reason to end the lockdown.

Reply to  Ian Coleman
May 4, 2020 7:20 pm


As nearly as I can tell, I’m just as stupid outside as in, and it doesn’t rain in here.

Eureka, Ian, you’ve solved a long standing puzzle for me. And to think, the missing piece was there all the time.

I don’t ever have to get wet again.

Thanks! You’re the best!

April 24, 2020 8:21 am

The discovery;
Mental functional impairment,
like rage, dumbness, stupidity, anger, madness, quick irrational thinking, moronic attitude etc.,
has a much clear and tight correlation with the atmospheric CO2 concentration increase than temp variation has. (according do current latest global data)

Some discovery there… where the hypothesis and the hype explanation offered quite silly and/but still proving the validity of the discovery, with it dumbness and silliness… 🙂

Got to face it, CO2 up mental schist up, mind fracking debilitating. 🙂
undeniable. 🙂


April 24, 2020 8:27 am

This is too easy…

Rising atmospheric CO2 has definitely affected the ability of some to think.

Steven Fraser
April 24, 2020 8:52 am

From the ‘Study’ (at

‘Early experimental studies testing for the influence of relatively high concentrations of CO2
(5–8%) that might be present in confined and enclosed spaces like submarines found significant impacts on ability to respond to a stimulus (Harter 1967), reasoning (Sayers et al. 1987) and threat processing (Garner et al. 2011). More moderately elevated concentrations (2.5%), such as those that may be present in passenger automobiles and aircraft, have been shown to impair visual perception (Yang et al. 1997) and ability to maneuver an aircraft (Allen et al. 2018).’ [emphases mine]

My thoughts: Wow, just Wow.

The title of the paper is ‘Fossil fuel combustion is driving indoor CO2
toward levels harmful to human cognition’

After reading their paper, which has more ventilation orfices in it than the modeled interior environments to which they allude, my impression is… that they have been spending too much time at low oxygen altitudes.

And, they never watched the movie ‘Apollo 13’. The CO2 partial pressure target max for the capsule was 8, which is equivalent to 10,526 ppm of CO2. If they are getting levels anywhere near that at CU Boulder, somebody needs to talk to the HVAC department.

Reply to  Steven Fraser
April 24, 2020 9:08 am

They no clue at all about what they are writing, my impression.

April 24, 2020 9:27 am

We all know the feeling: Sit too long in a stuffy, crowded lecture hall or conference room and many of us begin to feel drowsy or dull.

We all know that a properly prepared PowerPoint presentation can stun an Ox.

Andy Pattullo
April 24, 2020 10:33 am

CO2 cognitive sensitivity is very real but, fortunately, largely confined to folks who have already lost their marbles. Common symptoms are believing the world ends in 9 years, 3 months, 8 days and 13.2 hours, buying Tesla’s, eating excessive amounts of organic kale, wearing hemp-based clothes till the rash is so bad you need a burn unit and sending fawning greeting cards with sweaty half clad selfies to Mickey the Mann.

Andy Pattullo
April 24, 2020 10:41 am

By the way the air we breath out has about 38,000 PPM CO2. The efficiency of gas exchange in the lungs depends on the concentration gradient. Changing ambient CO2 concentration from 400 to say 900 ppm changes the gradient between air we exhale and air we inhale by about 1%. If the mental abilities of the CAGW crown can be impaired by that tiny change, are unable to raise their respiratory rate a trivial amount to compensate And can’t find the door to outside then there is no hope for them.

Andy Pattullo
April 24, 2020 10:44 am

Damn typing skills: crown should be crowd

April 24, 2020 12:30 pm

The authors are off by a factor of 10.
1000 to 1500 ppm CO2 is not significant to mammalian physiology.
Medical people generally know that there is no problem at 10000 ppm (1%)
Most people don’t notice anything at that level.
US health regulators, NIOSH, OSHA and CO2 MSDS say any concentration below 5000 ppm is not significant for people working 8 hours at that level.
Medical anesthesiology research in the 1930s experimented with CO2. For example
10 percent CO2 caused subjects to become unconscious within 10 minutes.

Scuba divers learn what CO2 levels can become a concern, but that’s a special case due to the pressures and other gas problems.
US submarine crews are well aware of potential adverse impact of CO2. I don’t remember the exact number, but the air monitor system did have a programmed alarm level. Maybe 1 percent. Normal operation was variable depending on crew activity levels.

April 24, 2020 12:37 pm

Come on Loydo, get typing.

A thread like this is nothing of a thread without your pearls of wisdom.

April 24, 2020 1:21 pm

“more than three times today’s outdoor levels and well beyond what humans have ever experienced.”

The amount of CO2 in your lungs varies between 20 000 ppm and 50,000 ppm during the breathing cycle, if you exhale very forcefully you can momentarily get it down to 10 000 ppm. No human has ever experienced lower CO2 levels than that.

Incidentally the breathing reflex is entirely tied to the CO2 level which is why hypoxia is so insidious, you don’t feel anything much, you just “fall asleep”.

Reply to  tty
April 24, 2020 9:37 pm

That’s a key point.

High Treason
April 24, 2020 2:04 pm

The real solution is to get rid of the oxygen thieves. They take the oxygen to convert to CO2. To add insult to injury, their hyperventilating and getting in to a chicken little type flap creates even more CO2 and takes ever more oxygen. Alas, their stupidity is so contageous(as bad as COVID) that it is becoming an overwhelmingly fatal cancer.

April 24, 2020 2:53 pm

My current pet dog thrives sleeping under the bed covers, sheet & blankets. When I 1st got it I had some anxious moments unbundling it at night to check it was O.K.

The animal probably is taking advantage of the way high CO2 levels in the lungs sustains high O2 levels inside tissue cells. Increased intake of cubic mm CO2/ hour gives the highest daily NAD+ levels since there is then relatively more NADH usage in the NAD+:NADH ratio.

It seems the dog, on a grain free diet, is not performing as much cellular glycolysis since that would have been using more NAD+(in Krebs cycle). The mitochondrial electron transport chain is what uses a lot of NADH & cellular oxygen is required there for dealing with electrons.

April 24, 2020 3:33 pm

Rising CO2 causes more than a climate crisis—it may directly harm our ability to think?

Reading this, one may presume that it already has…

Sweet Old Bob
April 24, 2020 4:10 pm

“By the end of the century, people could be exposed to indoor CO2 levels up to 1400 parts per million—more than three times today’s outdoor levels and well beyond what humans have ever experienced. ”

So ….. those on subs and in airplanes are not humans …


April 24, 2020 5:01 pm

Ironically, other “green” initiatives such as LEED certification may actually degrade indoor air quality (IAQ) including CO2 concentraiton, particularly when retrofitting older buildings.

“As another common example, outdoor air supply rates may be reduced in order to promote energy efficiency but without compensatory actions such as source control. This can increase concentration of pollutants indoors and reduce IAQ, especially in existing buildings that undergo renovation and retrofit. Tightening of building envelopes can also reduce outdoor air supply rates, which can reduce IAQ, if the volume of air that is infiltrating indoors is not brought back out by the ventilation system or if pollution sources are not concurrently reduced.”

Van Doren
April 24, 2020 5:43 pm

Can you actually think? If CO2 goes from 400ppm to 1400ppm, then O2 goes from 210,000 to 209,000ppm. You really think that can affect anybody? That’s roughly 130 feet height difference!

April 24, 2020 7:14 pm

Some years ago I was asked to do some finance consultancy work on a hydroponic tomato farm in central New South Wales. At the time I believe it was the third largest in Australia.

In the centre of the infrastructure there was a tower about 25 m high (from memory) this tower stored water which was continually heated night and day by a gas furnace. At night the hot water was piped through the glasshouse to keep the temperature from getting too low and inhibiting the growth of the plants. The exhaust gas from the gas furnace was treated to convert the monoxide to dioxide and exhausted into the glasshouse night and day. I don’t remember how high the CO2 concentration was but I remember being very surprised when I was told.

There was a team of about thirty women of varying ages working eight hour days in the glasshouse. Some were or had been pregnant.

The point. These children were perfectly normal academically, with a cross section of them going onto universities across Australia. No cognative disability on a developing foetus.

April 24, 2020 8:51 pm

We don’t need higher levels of CO2 concentration to permanently impair cognitive function in Americans. We have the progressive public school systems already doing the job quite well.

April 25, 2020 1:27 am

50 years ago Apollo 13 had to jury rig a lithium hydroxide scrubber (square peg round hole) because the carbon dioxide alarm was triggered, what was the concentration that triggered the alarm? In the film it was referred to as 15, which I presume is 15000 ppm.

April 25, 2020 1:34 am

This a COSHH (control of substances hazardous to health) sheet for carbon dioxide
which shows an eight hour limit of 5000 ppm.
This is from the U.K. health and safety executive

Pat from kerbob
April 25, 2020 9:20 am

Apollo 13
How were those guys able to construct their improvised CO2 filter with all that cognitive impairment going on?

John Sandhofner
April 25, 2020 6:52 pm

More doom and gloom prognostications. I think nature has a natural balancing mechanism that damps this effect. I suspect over time we will start to understand what it is. Most like it will be very complicated to the point we know it is happening but can’t fully model it.

April 26, 2020 7:17 am

The reason that CO2 levels are high in buildings is because of the efforts to be energy efficient during the oil crises. After that, buildings were designed to eliminate losses of heat (or cooling). A much higher percentage of the air is recirculated and buildings are now much better sealed from air leakage. In fact, back in the 1990s, there had to be an effort to increase the amount of fresh air and decrease the amount of recirculated air in buildings because the success of sealing the buildings led to negative effects of indoor air pollution on the occupants of the buildings.

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