All about CO2

Surprising CO2

CO2 has been around for long - almost right from the beginning of the earth. Is it any wonder there are many interesting and even surprising facts about CO2 that you may not know?

If you are in a mood to know something really cool and funny about CO2, this section is for you.


1. Could the killing of American Indians have caused climate change?

European killing of native Americans caused climate change and made earth cooler, says a report.

This interesting CNN report says that European settlers directly or through the spread of diseases killed 56 million indigenous people over 100 years in South, Central and North America. This caused large swaths of farmland to be abandoned, which got naturally reforested. The increase in trees and vegetation across a vast area resulted in a massive decrease in CO2 in the atmosphere making the earth cooler.

So, we are talking about global cooling here!

Read more from CNN & also from LiveScience

2. The industrial revolution might not be the first example of man-made climate change 

And while on Native Americans, it appears that the Native Americans might have beat us moderns to be the first to cause climate change from their activities.

This Ohio University study suggests that Native Americans left a much larger carbon footprint than originally thought.

3. CO2 and Roman “gate to hell”

Scientists have cracked the secret behind the Roman "gate to hell".

What the Romans thought was the deadly breath of the mythical hellhound Kerberos might be the familiar CO2, according to scientists.

In certain locations in the Roman empire, there were "gates to hell", locations where animals were sacrificed. Animals would be led by priests into a specific location and the animals would die with no human intervention but the priests accompanying them would come back alive.

How was this possible? The Romans obviously thought this was a miracle.

But scientists have figured out that the gates to hell were located above regions with high geological activities that gave out large amounts of CO2. This resulted in high concentrations of CO2 in those locations, sometimes as high as 35%, more than enough to asphyxiate and kill.

If that were the case, how did the priests survive? They either perhaps did not venture into specific zones within the gates of hell, or equally likely, their heights saved them.

Their heights? You see, because CO2 is heavier than air, the concentrations of CO2 emitted from under the earth would be highest in regions closest to the surface and decrease with height. The animals, which were of smaller heights compared to humans got exposed to very high concentrations and met their deaths while the priests survived - as long as they were not stupid enough to bend low enough!

Read more about this interesting intersection of CO2 and Roman history from Science & Live Science 

4. CO2 concentration in movie theaters

Is this the stuff that thrillers are made of?

Did you know that the CO2 concentration inside movie theaters could vary significantly based on the type of movie being screened?

We are not kidding.

If you think about it a bit, you will admit that this should not be surprising.

Many movie theaters will seat more than 300 people for a screening - that's a lot of people sitting inside a closed room for two hours or more.

If it is a dull and boring movie that makes you yawn, most audience are going to have pretty normal breathing, and if the movie had put some of them to sleep, their breathing is going to be a bit lower than normal. All said, the amount of CO2 inside the theater is unlikely to be super high for a dull movie.

What if the movie in front is a blood curdling thriller that keeps you at the edge of your seats and makes your heart beat like mad? The audience are going to be breathing heavily - and you can bet that no one will be asleep. Under these conditions, the CO2 levels are likely to be quite high.

Quite interesting, isn't it? Read more the research done on this from here & here

5. Book on CO2: The Story of CO2 - Big Ideas for a Small Molecule

A book on CO2, its various characteristics and diverse uses was published in Nov 2020, authored by Geoffrey Ozin & Mireille Ghoussoub.

The book's title is: The Story of CO2 - Big Ideas for a Small Molecule.

A reader describes it best - "It’s not a defense of the notion of climate change and it’s not preachy. What it is, is a positive look at what can be done about climate change, specifically about carbon dioxide".

More about the book from - Good ReadsAmazon

6. CO2 in special effects

Did you know that most time the fog special effects you see coming out on stage is CO2? 

Yes. In many of these shows, CO2 in liquid form (or in its solid form as dry ice) are used to create these effects. Once the liquid or solid CO2 is exposed to normal temperature and pressure, it instantaneously becomes a gas. As the liquid or solid CO2 expands into gas, it condenses the moisture in the surrounding air and together, these create the effects that you see.

Here are some interesting links that throw more light on special effects from CO2 - CO2MeterDifferent types of special effectsFog effects from Dry Ice - Tech notes from MITVideo - CO2 Dominator CO2 Special Effects machineVideo - CO2 Jet - CryoFX

7. CO2 -  A Movie

CO2 has also inspired a movie, titled - what else but - CO2. A 2010 American movie, it is about how a small American coal town is choked off by some mysterious, deadly vapours. It doesn't seem to have made it anywhere to the top of the box office. Wonder it it would have had it been released in 2021!

More about the movie from here - IMDB - Viewer ReviewsMovie trailer - YouTube,

8. Wars, armies & CO2

War machines are not just bad for the lives of people affected by them. They are also bad for the environment. As this interesting report says, if the Pentagon were a country, it would be the world’s 55th largest emitter of carbon dioxide.

Since the present era of American conflicts began with the invasion of Afghanistan in 2001, the U.S. military is estimated to have emitted a staggering 1.2 billion tons of carbon into the atmosphere, about 60 million tons a year on average (if we consider 2021 to be the end year for US involvement in the conflict).

Well, with China investing significantly in its defense and developing countries such as India keen on making a mark with their military prowess, it is a time for concern. Nationalism will win anyday over environment. Seriously, who really cares about CO2 emitted during wars - there are far bigger problems for the parties involved.

9. When faith decides whether CO2 gets sequestered or not

Some faiths believe in cremation - who are we to question that?

All the same, it might help them to know that cremation may not be the most environment-friendly way of seeing off their loved ones, as this Nat Geo article explains.

The science is fairly simple. By burning a body (which is composed of a lot of "biomass"), you are letting off CO2 into the atmosphere, not unlike burning wood. By burying the dead, you are sequestering the carbon in our bodies for many, many years.

10. CO2 for euthanasia

Given that very high concentrations of CO2 can lead to quick - and relatively painless death - it is not surprising that CO2 is used for assisted killing of animals before they are slaughtered. There is a fair amount of interesting literature and resources online with regards to the use of CO2 to kill animals. Whatever discomfort the animals have while dying from CO2 asphyxiation is likely acceptable for them compared to the truama they will undergo if they are slaughtered live. (The basic fact that they are being killed for someone's food will certainly not be acceptable for them, but that's quite another matter, isn't it?).

That raises the interesting question of use of CO2 for assisted killing of humans. There seems to be no evidence of the use of CO2 either in euthanasia (in countries where it is allowed), or in the execution of criminals. One of the reasons could be that the death from high CO2 concentrations might not be a quick and straightforward process as is death from hanging or from electrocution or through injections. While concentrations of 10% and higher will start leading to a host of problems, it might not result in immediate death.

The last thing one would want is to make dying a prolonged process - we are of course excluding special cases such as sadism and revenge!

11. Biodiversity & CO2

Researchers have known for a while that forests with a large animal population have more active carbon cycles, and also more carbon sequestered in soils as animals create waste, die and decompose, with a good portion of their carbon going into the soil.

2017 Stanford research effort has found that it is not just the number of animals, but also their diversity, that could have a bearing on the amount of carbon sequestered.

Why would it be so?

One reason, according to the researchers, is that a higher biodiversity could mean higher feeding interactions - animals preying on other animals or eating different fruits, with all these resulting in organic material left on the ground. The soil microbes then convert these waste remains into stored carbon.

12. Rock dust - an unlikely decarbonization hero

Spreading rock dust on farmlands could capture two billion tons of CO2 per year, says a study

In principle, this should not be surprising. Rock materials, during the weathering process, capture CO2 and convert it into carbonates and sequester it for a very long time.  Rock dust should be able to capture CO2 too, and perhaps even better as they have a larger surface area exposed to CO2, compared to rock formations.

So why cannot large CO2 emitting countries - which also conveniently happen to have large supplies of rocks or equivalent waste material - use this vast resource? And even more so when spreading rock dust could also possibly increase the fertility of the soils?

Why not indeed, we too ask.

13. CO2 & hurricanes

We have heard that CO2 induced climate change might cause hurricanes. But here's a new twist to the CO2-hurricane connection.

Rising CO2 levels could slow down hurricanes, says a study. And also goes on to say that that's not good.

We are sure all of you are screaming the same question: Why's that not good?

The slowing down is not good because it gives the hurricane more time to cause havoc and leave a larger trail of destruction with both wind & rain.

We reckon that the hurricanes could get slowed down somewhat, but not turned into pleasant winds!

14. Ants could be both accelerating and reducing CO2 emissions!

On the one hand, underground nests built by ants such as leaf cutter ants reportedly release 100,000 times the amount of CO2 from those soils than the surrounding soil surfaces, according to one study, which calls these nests "CO2 chimneys" - a fair enough term.

On the other, an Arizona State Univ study has found that some ant species help weathering minerals in using CO2 to produce calcium carbonate, and in the process sequester carbon.

Ants are indeed busy folks, one way or the other.

15. Using asbestos to sequester CO2 could solve two problems

Asbestos belongs to a group of silicate minerals composed of tiny, fibrous crystals packed tightly together. The material doesn’t pose much of a hazard when fully intact, but as these crystals break down and become airborne, they can enter the body and cause major health problems, including lung cancer.

Inhalation of asbestos fibers has been linked to lung cancer in many asbestos-exposed workers. As a result, asbestos mining has been banned in many countries worldwide.

But the closed mines exist with vast amounts of hazardous mine tailings still around. Interestingly, CO2 could prove to be a solution.

The very quality that makes asbestos so hazardous also makes it especially well equipped to pull carbon dioxide out of the atmosphere The vast surface area of certain types of fibrous asbestos makes them particularly good at capturing CO2 molecules dissolved in rainwater or even CO2 in the air. Using this property to their advantage, researchers have devised new methods to turn toxic asbestos mine tailings into innocuous piles of carbonate rock and draw down atmospheric CO2 at the same time.

The promise of using minerals to capture and store carbon dioxide is that it can be done on a massive scale—and would effectively store it away . forever. While asbestos presents excellent potential, mine tailings of other materials could be explored as well for CO2 sequestration. In a pilot project in 2019, a project funded by the diamond company De Beers and Natural Resources Canada used tailings from a mine in Canada’s Northwest Territories to capture carbon dioxide. The objective was to evaluate the possibility of using minerals to capture and store the gas from the flue stream of a power plant.

Web resources:

16. Marathons & CO2

Who would have thought that someone would be discussing marathons in the same breath as CO2? But we are doing it here.

An interesting analysis was done to assess whether marathon running contributed to global warming. This research was motivated by the fact that a marathon runner will give out nine times more CO2 during his run compared to a sedentary individual.

Estimates suggest there are about 3000 marathons worldwide every year, and about 10 million people participate in these marathons. That's a lot of extra CO2 released.

But in a way they should not have bothered because human breathing - howmuch ever it is - does not contribute to climate change as the CO2 breathed out had come from the food they ate, which originally was captured from the atmosphere.

A short and abrupt answer to an intriguing question, but we included it here because it tells us something we would not have thought about - that we breathe out a heck of a lot more CO2 when we are running or are super active compared to our times on the couch!

17. Human/animal waste & CO2

Animals - both stray animals and those grown in an organized manner by the industry - deposit humongous amounts of waste every day, and a good lot of these get composted in the soil, resulting in CO2 emissions.

In many underdeveloped & developing countries, fecal waste - human waste deposited on land - is also a rampant phenomenon and these too release CO2 when they are composted.

Is this a problem?

From a climate change perspective, these emissions are carbon neutral. The carbon in these waste was originally captured by plants from where we get our food, and which turn was converted into waste by our bodies. So these CO2 emissions do not add anything extra to the atmosphere as they are releasing back what was originally captured from the atmosphere.

18. It happens only on Mars - CO2 snow

The atmosphere of Mars is (almost) full of CO2, with a 95% concentration.

While scientists have earlier recorded snow composed of water falling on Mars, they recently confirmed that the snow in the southern hemisphere was composed of CO2.

This is the only known instance of CO2 snow anywhere in the entire solar system.

19. Dinosaurs & CO2

By now, you would have anticipated dinosaurs to make an entry sometime.

And here they do.

You would have been familiar with the commonly accepted hypothesis that the dinosaurs were wiped out owing to a large asteroid or a meterite crashing into the earth, resulting in a massive amount of dust, volcanic eruptions and other environmental changes that eventually killed all the non-avian dinosaurs. 

recent study has estimated that the asteroid impact could have created massive emissions of CO2 from rocks and from wildfires. Such large emissions could have resulted in a massive 5 degree C temperature increase that happened, and which stayed that way for about 100,000 years.

But while such a large increase in temperature would have had a disastrous effect on dinosaurs (and many other species on earth), not everyone agrees that global warming was the sole or even the dominant reason for the extinction of dinosaurs.

second theory holds that the "impact winter" following the asteroid impact could have killed the dinosaurs. According to this hypothesis, the asteroid impact released so much dust and soot into the atmosphere that blocked sunlight making the subsequent winters really cold, and this cold killed the dinosaurs. Interestingly, according to this hypothesis, the parallel volcanic eruptions happening in the Deccan region of India (unconnected to the asteroid impact) might have indeed kept parts of the world warm during the cold winters in the years immediately after the asteroid impact and could have helped some species survive. So, CO2 emissions and global warming could have actually helped some species survive rather than make dinosaurs extinct, according to this hypothesis. 

And a third hypothesis is that both the volcanic eruptions and the asteroid impact were responsible for the extinction of the dinosaur, as both would have resulted in global warming in the long term.

20. Sound of climate change

Climate change is surely not music to our ears, but there are folks making music out of climate change.

Really. Here are some examples - here and here

21. The colours of CO2

Did we not say that CO2 was colourless? We indeed did, and that, we assert, is the truth.

But some folks are unreasonable. They go ahead and give colours to CO2.

But we cannot really complain, because they have a reason to do this.

So what colours have we got here for CO2?

22. CO2 & crime

We all can understand the social and economic consequences of crime, but someone wanted to take their understanding further. What would be the environmental consequences of crime. Specifically, how much CO2 emissions would criminal activities result in?

The researchers appear to have given the whole thing serious thought, for they had come up with a comprehensive and sophisticated methodology to compute this.

And they came up with an answer for the UK - 4 million tons a year. Given that the UK's CO2 emissions are about 350 million tons a year, that would be more than 1% of total CO2 emissions.

At this rate, we should not be surprised if a carbon penalty is also added to the other penalties imposed on criminals. 

23. CO2 & smoking

Smokers should surely be far more worried about the dangers of tobacco than anything that has to do with CO2?

Well perhaps, it appears CO2 is very much part of this game. 

Studies have found that the CO2 in the smoke smokers inhale is largely responsible for the inflammatory effects of tobacco smoke.

In a study published in 2010, the authors assessed the inflammatory potential of carbon dioxide contained in cigarette smoke. Mice were exposed to cigarette smoke containing a high or reduced CO2 level. Data showed that the toxicity of cigarette smoke may be largely due to its high level of CO2. Pulmonary injuries consequent to tobacco smoke inhalation observed by histology were greatly diminished when CO2 was removed.

CO2 can kill in more ways than one. 

24. CO2 can make you dumb

Can high CO2 levels affect cognition enough to make us fumble in our thinking and activities?

Some basic concepts suggest a connection: When we breathe air with high CO2 levels, the CO2 levels in our blood rise, reducing the amount of oxygen that reaches our brains which can increase sleepiness and anxiety, and impair cognitive function.

While research studies do not yet appear to have made reliable correlations between CO2 concentrations and cognitions, large amounts of empirical data seem to corroborate decline of cognitive powers with increase in CO2 concentration. 

Given that indoor concentrations of CO2 can exceed 1000 PPM in some cases in closed rooms, and where many of these folks are expected to do focussed, intelligent work, this domain certainly requires further research. In parallel are also required recommendations on how to reduce high CO2 concentrations within such environments.

More on this topic from hereherehere & here.

And while CO2 concentrations in closed environments, this analysis suggests an optimal CO2 level inside rooms might also be important for a good sleep.

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