Carbon Dioxide: the Minor Greenhouse Gas
It is time to take a DEEP breath and take a common-sense look at the real (non-political) data. UPDATED 07/06/2022
Few people seem to be aware of the Number One greenhouse gas on our planet:
Each year, Dihydrogen Monoxide is a known causative component in many thousands of deaths and is a major contributor to millions upon millions of dollars in damage to property and the environment.
Some of the known perils of Dihydrogen Monoxide are:
Death due to accidental inhalation of DHMO, even in small quantities.
Prolonged exposure to solid DHMO causes severe tissue damage.
DHMO is a major component of acid rain.
Gaseous DHMO can cause severe skin damage.
Contributes to soil erosion.
Leads to corrosion and oxidation of many metals.
Contamination of electrical systems often causes short-circuits.
Found in biopsies of pre-cancerous tumors and lesions and also in actual cancers.
Often associated with killer cyclones in the U.S. Midwest and elsewhere, and in hurricanes including deadly storms in Florida, New Orleans and other areas of the southeastern U.S.
Thermal variations in DHMO are a suspected contributor to the El Nino weather effect.
Add to this the damaging greenhouse effects, and we must urgently press to have it banned completely worldwide.
Unfortunately, doing so might prove difficult because Dihydrogen Monoxide is just another chemical name for water.
But in the case of Global Warming (aka Climate Change) water vapor is the Number One Greenhouse Gas – and by a wide margin. Not only is it 50 times more abundant than carbon dioxide, but it also has a much stronger effect. Obviously there is nothing that the Climate Alarmists can (or should) do to control water vapor. Unfortunately, they focus sharply on the very minor and secondary Carbon Dioxide.
The famous "Blue Marble" picture taken of the Earth during Apollo 17 caught the world's attention. Today, similar pictures are caught day and night by weather satellites to monitor cloud cover and hurricanes.
(A Global Warming Day:) (A Neutral Day:) (A Global Cooling Day:)
Fig. 1. "The Blue Marble".
Your eyes are telling you something... The picture on the left looks dark. On a day of light cloud cover, significantly less sunlight is reflected back out into space. The picture on the left is "one day of global warming." The picture on the right shows significantly more sunlight reflected back into space (cloudy days are cooler): "one day of global cooling". These days more or less average out over a typical year.
Prolonged and significant warming will eventually increase the amount of water vapor in the air. This will result in more average clouds, which in turn will reflect more sunlight and produce less warming. In other words, clouds have a negative feedback effect that tend to minimize global warming and regulate global temperatures.
This is of course vastly over-simplified. The effects of water vapor are in fact so complex that they end up being chaotic. If you attempt to include these effects in a computer model, the results are simply "all over the map", so to speak. It is difficult to predict the weather (even locally) out to one week. But 10 or 100 years?? The scientist who is doing the modeling is forced to enter his estimates for the effects (realistically, his biases) in order to force the model to behave "better". As a result, the output of the model can look like virtually anything the modeler wants it to. This bias is sometimes not conscious, but very real anyway.
But there is “an elephant in the room”. Ignoring the water vapor renders the results meaningless. "Modeling" the water vapor on the other hand turns the "computer model" into simply an opinion. The real problem is that the general public tends to believe even a wild opinion, if it is given the respectability of a "computer model".
But let's get down to basics. At the start of the 2020 election campaigns, some candidates were proposing trillion (with a 't'!) dollar programs to control our carbon emissions. Just follow the money!
Consider the actual effect of carbon dioxide to the balance of radiation received and what is re-radiated out to space. “Greenhouse Gasses” trap bands of infra-red radiation (heat) that are trying to escape into space. (on the right in this graph)
Fig. 2. Water vapor actually accounts for most of the absorption spectrum of the atmosphere. Carbon dioxide has rather narrow absorption bands (which are mostly already absorbed by water vapor anyway) and has only 1/50th the concentration. Note that the absorption profile at 2,000 ppm carbon dioxide does not look very different from 400 ppm!
While this illustration is basically true, the finer details are even more compelling.
In the “Total Absorption and Scattering” plot, (Fig. 2) note that: (1) The two areas circled are the only portions of the spectrum that are significantly affected by carbon dioxide, and (2) Once absorption reaches 100%, the sky “looks black” at that wavelength (no radiation is passing). Adding more carbon dioxide has little effect. The absorption peak will look slightly wider as the side slopes get steeper, but “black” (100% absorption) is still black. That means that a simple linear extrapolation of current temperature rises is unrealistic and exaggerated. (See Figure 5) For a more detailed discussion, go to 0:29:00 of Burt Rutan’s video. (Below)
The ultraviolet radiation (and some blue) is mostly absorbed or Raleigh-scattered by the air and the ozone layer. Water vapor absorbs some bands of near infrared light, warming some air layers where water vapor is highest.
You have to look rather carefully to note the differences between the absorption and scattering by water vapor compared to the total – including the carbon dioxide. I marked the contributions of carbon dioxide to the total absorption. It is small.
There is an absorption peak around 4-5 micrometers which is distinctly by carbon dioxide, but there is very little actual radiation in that band, so it is rather trivial. Radiation in the main carbon dioxide absorption peak around 13-18 micrometers would be partly absorbed by the water vapor anyway, so the carbon dioxide makes only a small change in the total absorption spectrum.
Think of this “spectral window” like your car window. In order to cool your car, you want to add some tinted film. You apply a 2 inch wide strip of film to the window, but it doesn’t seem to do much good. It is advertised to absorb 50% of the sunlight. If you look through the strip, it is like wearing sunglasses, but the glare from both sides is still disturbing. So you add a second strip on top of the first, but it does not make any noticeable difference cooling the car.
Doubling the tinted film cuts the light in half again – to 25%. Adding one more strip only reduces the light by 12.5%. You get diminishing returns.
But the glaring problem is that the entire rest of your window (representing the rest of the spectrum) is totally unaffected by even large increases in Carbon Dioxide.
When you compare the 400ppm window with 2000ppm (a drastic five times increase), the difference would go unnoticed if they were not shown together.
I am not sure about how these plots were assembled, but there is another pertinent fact: THERE IS 50 TIMES AS MUCH WATER VAPOR AS CARBON DIOXIDE IN THE ATMOSPHERE.
In David Siegel’s presentation, he pointed out that Water Vapor raises the Earth temperature about 25 degrees above “blackbody equilibrium”. In other words, Water Vapor supplies that much “Global Warming”, while Carbon Dioxide is only providing about 4-5 degrees with the first 50ppm, and another 1-2 degrees by the time we got to 400ppm. Ozone provides another 2-3 degrees. We are currently about 33 degrees above “blackbody equilibrium” (i.e. “Global Warming”)
Even though water vapor is 50 times more abundant, it only causes about 10 times more warming. That implies that the overall effect of Carbon Dioxide is about 5 times stronger.
See: http://nov79.com/gbwm/satn.html
For another powerful argument on carbon dioxide saturation by Dave Siegel, see: ( I fast-forwarded it to the section on Carbon Dioxide, but I strongly recommend rewinding it next time to watch the whole presentation)
Carbon dioxide absorbs all radiation available to it in traveling just 10 meters in the near surface atmosphere, which is called saturation. Doubling the amount of CO2 shortens the distance to 5 meters. Shortening the distance is not increasing the heat.
This raises an interesting puzzle in David Siegel’s plots:
If Carbon Dioxide absorbs the radiation within 30 feet, then why does it not cause the dip to go down to zero, even at 800ppm concentration?
When a CO2 molecule absorbs infrared, it does so selectively by exciting an orbital electron from the ground state to a quantum allowed and preferred state. It can quickly re-emit a photon by dropping back down to any quantum allowed and preferred ground state, or even another excited state. A “shorter drop” will be a much lower energy (longer wavelength) photon. But the CO2 is only 0.04% of the atmosphere, so the overwhelming probability is that it will be absorbed by a water vapor molecule (which is 50 times more abundant, and quite happy to absorb photons in this band). Once the energy is transferred to a water vapor molecule, it can be re-emitted at any other wavelength that completely bypasses any further interaction with CO2 molecules.
Gas molecules are also constantly undergoing enormous numbers of elastic collisions which randomly redistribute the heat energy. CO2 is in such a minority that “about 2499 out of 2500 times”, it will collide with a Nitrogen or Oxygen molecule and randomly redistribute its “excess energy”. From then on, that excess energy is free to bypass any further interference from CO2 molecules.
So for anyone searching for a “Global Warming Smoking Gun”, Carbon Dioxide is a poor choice.
First, it only “traps” a narrow slice of the spectrum.
But second — and paradoxically — it is “too strong”. Within only about 30 feet, CO2 literally absorbs every photon that it can grab. But in so doing, it quickly seems to scatter the energy outside of its “reach”.
Actually asserting some meaningful control over carbon dioxide raises yet another embarrassing problem for the Climate Alarmists:
Fig. 3. Burt Rutan's excellent graphical illustration of the concentrations. Human-generated concentration is barely even visible.
(For more from Burt Rutan, see:)
(For complete coverage:
https://rps3.com/Page/Burt_Rutan_on_Climate_Change.htm)
The total human contribution to carbon dioxide “pollution” is only 3.4%. Most of the carbon dioxide "pollution" comes from nature. So a multi-trillion dollar “cleanup” of human activity would affect only a small fraction of 3.4% of the atmospheric carbon dioxide – which itself is only 3.62% for the total greenhouse gases. Human activity accounts for only 0.123% of greenhouse gasses. A truly massive effort by a totalitarian One World Government might achieve a 20% reduction in anthropogenic (human) carbon dioxide: a 0.025% reduction of Greenhouse Gases:. Furthermore – as pointed out before -- carbon dioxide itself has only a minor effect on total greenhouse effect as compared to water vapor.
Fig. 4. Let's put things in proper perspective.
If we zoom out to view the whole atmosphere, you can see (with a strong magnifier) what a tiny “handle” carbon dioxide gives us on the control of Global Warming. So if you "only" spend $10,000,000,000,000 on emissions control worldwide, you accomplish virtually nothing.
But there is even a far more basic question: Does carbon dioxide actually cause global warming?
Fig. 5. The long term history.
Global temperature trends over the last 600 million years will give us a better view of “the Big Picture”. Earth naturally goes through a series of warm periods and ice ages. We are currently at the tail end of an ICE AGE. Several things should be noted from the plot above:
1) There is a strong “negative feedback” effect that makes the global temperature self-regulating. There appear to be hard limits on the maximum and minimum temperatures where the negative feedback takes firm control. This ultimately largely negates the effects of carbon dioxide. The hard ceiling on temperature is probably largely due to the saturation effect on carbon dioxide that I mentioned earlier.
2) There were “three and a half” previous ice ages in this period. We are towards the end of an ice age that never quite reached the hard lower limit. The Earth has been considerably warmer during most of past history, and yet life on Earth survived just fine.
I should point out that cold weather is vastly more dangerous than hot weather. Relatively few people die from heat, but a hard freeze is a real and immediate emergency. Canada has substantially more territory than the United States, and yet they have only 1/10th the population. Most of them are huddled within one hundred miles of the US border. Their northern regions are frozen for 6 months a year. This should tell you that the current world temperature is not optimum, even for mankind.
The Climate Change Alarmists claim that carbon dioxide is the main cause of Global Warming -- and it is OUR FAULT. Let’s examine the facts.
The current average temperature hovers around 14.5 degrees centigrade (58 degF), and the carbon dioxide content of the air is around 400ppm. (That is only 0.04% of the atmosphere.) Carbon dioxide levels have been as high as 7,000ppm (17 times higher than today). During that time the whole Earth was a rain forest. Life on Earth thrived. Some 300 million years ago carbon dioxide levels got down to 180ppm. That was dangerously low. At 150ppm most plants die, and the rest of life follows shortly.
The optimum level for carbon dioxide is probably at least three to five times higher than today. At those levels we could feed the world population. Rain forests would expand. Crop yields would increase dramatically, and in many cases the farmer could harvest multiple crops every year.
There is a happy irony here. Carbon dioxide levels are indeed rising. There is little use in arguing that point. But, SMILE!! Satellite global surveys show an increase of over 10% in vegetation worldwide. Stop calling it "Global Warming". "Global Greening" may be more accurate. Furthermore, it is becoming increasingly evident that the earth may actually not be warming at all, or even starting to cool. Think of it! Abundant crops and lower air conditioning bills! That is a win-win situation.
Fig. 6. The correlation between temperature and CO2 is very weak.
It should be obvious from the figure above that we are way below even an average level for both temperature and carbon dioxide. And that average is also probably way below optimum levels. It is also evident that carbon dioxide is at most a minor contributor to the Earth's temperature profile. Shouldn't we be focusing on finding the prime influences?
One thing that is genuinely confusing many people is that some computer models seem to clearly show a connection between carbon dioxide levels and global warming. Unfortunately, the global weather system is so complex that it is totally impossible to model it with any degree of confidence. I might also point out that the models have consistently been proven wrong within a few more years of reality. If you take the upper limits and lower limits of all IPCC models, the actual warming has turned out to be less than the lowest model. The modeler has to make certain assumptions: how much effect does carbon dioxide have? The central problem here is that water vapor in the atmosphere is too chaotic to model. Water vapor is partitioned into ice, water and vapor reservoirs. Their effects are quite different. In the air, water can be a vapor or liquid (water mist in the clouds.) Depending on their altitude and density, clouds can either reflect more radiation from the Sun back into space, or absorb it. Thus it can have a positive or negative coefficient locally or over vast areas. Variations can be hourly, daily, weekly or seasonal. So the models make little attempt to actually model the water vapor. They would be inaccurate if they did, anyway. But water vapor is about 50 times more abundant in the atmosphere than carbon dioxide. And do not lose sight of this fundamental fact: the overall effect is a self-regulating negative feedback that has reliably kept Earth temperatures within safe limits for life for millions of years.
If you look at the averages of 102 computer simulation runs (in 32 groupings) you will see that they were virtually ALL embarrassingly WRONG. The estimates were all WAY TOO HIGH. You probably didn’t even notice, but there was one group (lower right) that actually came quite close to predicting the actual measured data!
So with major poorly defined or virtually unknown variables the modeler must “adjust” the model parameters and examine the results. Unfortunately, they already “know” what the results “should be” and the model can show any “result” desired. Unfortunately, what the results “should be” is largely determined by the peer group in which you circulate. Hence the bias within the group-think ultimately ends up in the adjusted computer models. But we have to be careful, since that same principle can operate in both directions. So the main caution is against over-reliance on models in a field where realistic models are simply not practical. Stick to the science!
These models could actually be somewhat useful. If you continue to re-adjust the parameters after-the-fact so that the old predictive models will eventually match present outcomes, those parameters can not only provide useful insights, (which parameter produced the best results?) but can make future projections more accurate. That does not seem to be happening. Predictions made 15 years ago have consistently been shown to be highly exaggerated. They continue to predict doom, even though there has been virtually no global warming in the last 17 years. They are switching increasingly from using the term “Global Warming” to calling it “Climate Change”. Do I believe in Climate Change? Yes, absolutely! Climate has always been in a state of change. But they got it all wrong. They are concentrating on a gas that has a very weak effect on global temperature, and we can only hope to partially control about 4% of that. So if we spend $1,000,000,000,000 (one trillion dollars) on humanity's carbon footprint, we might reduce our U.S. emissions by 10%. That would only achieve a 0.4% reduction in total atmospheric carbon dioxide, which is already only 0.04% of the atmosphere. That is the ultimate futility... Furthermore, we can only control OUR emissions with OUR trillion dollars. We can’t force China to spend one trillion dollars on their pollution. And the results would be minimal anyway.
There actually IS a relationship between water and carbon dioxide that is easy to understand and even easier to demonstrate. Take two cans of Coke. Put one in your Styrofoam cooler with plenty of ice. Leave the other out, and go to the beach. When you open the cold Coke, you will get a weak little "pfffft!". But point the other one away when you open the warm one, or you may get drenched in spray. Carbon dioxide is much more soluble in ice water than it warm water.
There are some 200,000,000 cubic miles of water in the oceans! That is an enormous reservoir of heat. It is also an enormous reservoir of carbon dioxide. It takes decades to substantially change the carbon dioxide content of the oceans. It also takes decades to hundreds of years to change the ocean temperature as a whole, but there may be local warm or cold currents which affect local weather. The best known of these is the Gulf Stream.
When the oceans gradually warm, they begin to slowly emit excess carbon dioxide back into the atmosphere. But this takes hundreds of years to re-establish equilibrium because it takes that long for all 200 million cubic miles of water to get a "turn" near the surface. So changes in both the oceanic carbon dioxide and atmospheric carbon dioxide lag behind the temperature changes. They keep putting the cart before the horse.
Meanwhile, forests and crops grow to put any "extra" carbon dioxide to very good use. Remember that roughly half of those vegetables you eat came directly (by photosynthesis) from that "evil" (but actually rather scarce) carbon dioxide in the air that we are trying to reduce. When there is insufficient carbon dioxide in the atmosphere (such as recently), desertification happens. Fortunately, we are beginning to turn that trend around. So if you really want to save the rain forests, buy a SUV! But it is not just your salad that comes "from thin air": the meat we eat comes (indirectly) from grass. The lumber for housing was extracted from the air reserves of carbon dioxide. In short, virtually everything organic depends on a supply of carbon dioxide -- either directly or to provide food.
Fig. 10. Updated IPCC temperature projections, even if no further corrective actions are taken. (Save the trillion dollars!) If the model is correct, the temperature may go up by 1.0 – 1.3 degC in another 80 years, IF WE DO NOTHING. We have plenty of time to work on it!
Like DHMO, carbon dioxide has gotten a bum rap. In the case of DHMO (aka water, in case you forgot!) it was just a harmless prank. The attack on carbon dioxide is deadly serious and highly detrimental and costly. So let’s set the record straight: CO2 is almost as good a friend as DHMO. It is definitely the friend of trees and plants. Carbon dioxide is plant food -- more important than fertilizer. When you eat fruits or vegetables, remember that about half of that was built directly from the rather scarce carbon dioxide in the air: only about 0.04%. So this is also true of all living things that need nutrition. (So TALK to your plants for two hours a day! They will grow better with your carbon dioxide! ;>) Increasing (or decreasing) your “carbon footprint” will have negligible effect on the future of humanity. If you have a choice, opt for the higher carbon footprint. The trees will love you! All plants love 800 ppm or more. And plants are the foundation of our food chain.
On a global scale, the effects of this increase in carbon dioxide are evident:
Fig. 12. The total world wide increase in leaf area is roughly equivalent to two times the continental United States.
In addition to simple area increase, at higher carbon dioxide levels plants are able to grow in dryer areas and require less irrigation. They can grow in poorer soil. At 800 parts per million (double the CO2!) we could perhaps feed the worlds population! Fighting world famine certainly seems like a noble goal.
It should be obvious, but it is important to realize that the United Nations Intergovernmental Panel on Climate Change (the “IPCC”) is after all primarily an Intergovernmental Panel. That is to say, its primary function is to organize government legislators and departments to deal with the politics and logistics of the "problem". These are primarily political functions. If there is a real problem, then legislators can tax it and regulate it. Thus, they have a vested interest in Global Warming, since it gives them power to tax and regulate. Legislators in turn provide funding for research that empowers them.
So, was President Trump a “Global Warming Denier”? No, he is simply NOT a Global Warming Dupe. That is another important distinction.
Few seem to notice another important distinction: A record breaking cold winter is somehow blamed on “Global Warming”. The more proper term is “Climate Change”. But of course, the only thing that is really “constant” about the weather is change. They have difficulty predicting the weather for a week. So lotsa luck on 100 years!
There were 2,500 scientists who signed the IPCC declaration on global warming. But the agreement was far from unanimous. On the other hand there were 31,487 scientists who signed the Global Warming Petition Project: a protest against that nonsense.
Unfortunately, that is an exercise in futility. You can’t vote on truth. A lie is still a lie, no matter how many people believe it. The truth is still the truth, no matter how many people deny it.
In the interest of healthy and open scientific debate, let’s examine some real progress made so far.
There have been major efforts to "clean up the environment". We have tight emission controls on automobiles. This has greatly reduced the amounts of nitrous oxide and carbon monoxide in the exhaust, not to mention tetraethyl lead Carbon monoxide is dangerously poisonous. These gases contribute to smog. Bringing these under control is of course a good thing, but it has come at a substantial cost and increased complexity. These controls have also improved the gas mileage, reducing the amounts of gasoline burned. But then of course the gains in fuel efficiency are small compared to the massive increase in the number of vehicles on the road.
But there is one unfortunate fact to point out: burning one gallon of gasoline still produces the same amount of carbon dioxide. This is simply called stoichiometry. You can't change that basic chemistry of combustion. A modern car actually produces more carbon dioxide per gallon than a Model-T Ford, only because it burns it more completely. So aside from increased gas mileage, there is ZERO fundamental improvement here.
The same can be said for cleaning up the emissions from industry. Ten years ago driving to work I drove every morning through the delightful aroma of baked bread. The EPA forced the bakery to "clean up" those “polluting” emissions. OK, sometimes it gets ridiculous. Some of those bureaucrats have WAY too much time (and authority) on their hands. On the other hand, reducing the sheer volume of smog and soot and pollutants saves many lives and makes life in general much more pleasant.
But once again, all of this has little to do with our so-called "carbon footprint". Combustion remains fundamentally unchanged. The issues of pollution and energy efficiency should be kept separate. "Carbon footprint" is probably a non-issue.
We need to have a completely open and honest dialog (and even debate) over these issues...
So remember the basics:
1) Carbon dioxide levels today are way below historical averages, and probably way below optimum.
2) Carbon dioxide is by no means the principal "Greenhouse Gas". That distinction goes to water vapor, by a factor of 50. But don’t try to ban water.
3) We have gone through a series of "Global Warming" cycles, each followed by a rapid "Global Cooling" cycle. Why should this cycle be different?
4) There are indications that we may be near the end of this warming cycle. There has been no global warming for the past 18 years. We may see significant cooling in 100 years.
5) We should welcome the rising levels of carbon dioxide. We are still far below average, and probably also far below optimum. We need more carbon dioxide to fight famines.
6) Even if we want to control carbon dioxide, our grip on the problem is so tiny and weak that the effort is futile. We can't significantly increase it or decrease it, no matter how much money we spend..
So let’s put our efforts into adapting to changes. That is what the human mind has always done. Let's optimize our response to the changes. Those who do will reap huge rewards.
But there is nothing even close to a consensus on "Global Warming/Greening".
There is a desperate effort to ram through legislation on Global Warming before it implodes of its own weight of nonsense.
Talk to your plants! Give them the love and carbon dioxide they need. ;>)
Dave Harris