CO2 is Not Driving Global Warming

In the latest legislative session in Washington state, Gov. Jay Inslee proposed a carbon tax which will penalize anyone the government deems is producing an excessive amount of CO2. The stated purpose of this tax to mitigate the damage caused by global warming that results from CO2 being released into the atmosphere.

This punitive tax is based on poor science, circular reasoning and media-fueled hysteria. Any effort to curb CO2 emissions will do exactly nothing to affect worldwide temperatures, if they are even a problem. I will prove this here.

I'm a NARTE certified electromagnetic compliance engineer with more than 30 years practical experience in high power radio frequency and microwave applications. The principles of radio frequency propagation and free space loss in the RF frequency domain are identical to the infrared region. My critique of the CO2 driven climate change theory is based on a practical understanding of the intersection between chemistry and electromagnetic theory. I'm also a systems engineer with plenty of experience in software design and development. I’ve had a lifetime fascination with astronomy and cosmology, which has given me an intimate familiarity with the principles of spectral absorption which are necessary to understand CO2’s role as a greenhouse gas. I acknowledge the work done by climatologists based on their study of global trends and their comparative studies of CO2 levels. I challenge their conclusions, based on the understanding of how CO2 acts in the atmosphere; and suggest that they explore alternate explanations for their observations.

This explanation is going to be technical, but I will explain the principles as I go, and anyone with a science background can duplicate my analysis.

Global Warming (or is it Climate Change?)

No one was even aware that a problem existed until 2006, when former VP Al Gore grossed $24 million in box office sales with his propaganda-laden exposé, An Inconvenient Truth. Gore filled an hour and forty minutes with anecdotal evidence cherry-picked to support his claims, claiming that 97% of scientists supported his conclusions, even though nothing of the sort was true. The linchpin of his proposal was a study by Mann, Bradley and Hughes, which resulted in the famous hockey stick graph. Gore projected this graph into the future and predicted dire consequences as a result.

Without even studying the basis for this claim, this set my alarm bells ringing. Climate is a chaotic system. It’s a system with dozens, if not hundreds, of attractors which influence the end result. Small changes in any one of the systems or attractors that influence climate can have dramatic effects on the overall system. This is the very definition of chaos.

Anyone who is studying chaos theory knows that chaotic systems tend to behave similarly, even if they have nothing to do with each other. Another example of a chaotic system which frequently generates short-term trends like Al Gore’s hockey stick graph is the stock market. What Al Gore is essentially doing is looking at a short-term trend, projecting it forward and concluding that huge profits are in store. Anyone who's a done any trading in the stock market knows that this is a fallacy. Yes, sometimes short-term trends turn into long-term trends, and if you invested at the beginning of the short-term trend you can turn a handsome profit. The problem is that chaotic systems have feedback loops, and the feedback loops have feedback loops, and nine times out of ten your short-term trend is going to reverse the moment you invest. If Al Gore is such a fan of projecting trends, he should become a stock market analyst and get rich. Good luck to him.

I figured in 2006 that the short-term hysteria that he generated would soon be forgotten. But Al Gore wasn’t about altruistically warning us about an ecologic disaster. His movie was the opening salvo of a marketing campaign designed to make billions of dollars through the creation of a carbon credit exchange, where large producers of CO2 could “buy” carbon credits from others who didn’t produce CO2. This exchange would function just like the stock market, with the market makers taking a cut off of every transaction. Of course, Al Gore was setting himself up to be one of the market makers. Gore spent huge amounts of money promoting his climate change religion, literally going on tour to convince people to invest in his carbon exchange. He used his political capital to influence sitting lawmakers to pass legislation to support his scheme. Tremendous amounts of money were spent in the form of grants to generate studies that validated his hypotheses, using studies designed around a predetermined outcome, frequently based on circular reasoning.

Is It Science, Politics or Religion?

Global warming became a religion. Religion is based on a belief that cannot be verified by the average person, based on testimony by a select group of priests and prophets. Heterodox opinions and evidence are condemned as heresy, and those who voice them are shunned, ostracized and subject to derision. Voice any skepticism to global warming in a public forum, and observe the hysterical condemnation of your skepticism, based on the Orthodox Scripture of global warming, quoted by people who are essentially scientifically illiterate and incapable of understanding the underlying science of climatology, let alone capable of seeing the holes in the theory.

The foundation of the climate change theory is based on data that suggests a general worldwide warming trend. There's considerable controversy as to whether this warming trend is unusual in the long-term, whether it’s an artifact of the data collection methods, whether the data has been manipulated to demonstrate a foregone conclusion, or even whether the data collected is reliable, given the advances in data collection technology that have occurred over the period in question. I don’t propose to answer any of these questions here. Global temperatures may indeed be rising. The fact is that global temperatures have never been constant throughout the geologic history of the planet.

The foundation of the Anthropogenic Global Warming (AGW) theory is based on data that shows a correlation between atmospheric CO2 levels and global temperatures. The assumption is that CO2 is a greenhouse gas, and that CO2 levels drive planet surface temperatures. Any scientist worthy of the name knows that correlation is not necessarily causation. I aim to show here that changing CO2 levels at the current concentrations have absolutely no effect on the atmospheric energy budget of planet Earth. I will demonstrate that while CO2 is a minor greenhouse gas, it has already made its full contribution to the temperature of the Earth, and that additional CO2 will have no effect.

The Electromagnetic Spectrum and a Primer on Heat

The study of electromagnetic theory has some fascinating applications. Climate change argument aside, you’re about to learn some really interesting stuff.

Electromagnetic waves consist of an electric field and a magnetic field 90° to each other. These waves vary in frequency, from very low frequency waves that take tens of seconds to pass by all the way up to x-ray and gamma ray radiation. Electromagnetic frequencies are measured in hertz. One hertz means one wave per second. We’re familiar with radio waves in the megahertz region that we listen to in our cars. Radars operate in the low gigahertz region, what we call microwaves. Infrared energy we feel as heat. Our eyes are sensitive to a certain band of electromagnetic radiation we call light. Above that you have ultraviolet, x-rays and gamma rays.

The chart above shows the electromagnetic spectrum in terms of wavelength. It’s backwards to what I’m used to, because I work with frequencies, which are the inverse of wavelength. Most infrared studies deal with wavelengths instead of frequencies, so we’ll use that.

In the year 1900 physicist Max Planck pioneered a study of electromagnetic radiation which demonstrated that any body with the temperature above absolute zero radiated electromagnetic fields. Planck’s formulas showed that the higher the temperature of the body, the higher peak frequency of field it emitted. He postulated an ideal black body radiator, which is a model to approximate the radiation of anything with a temperature above absolute zero.

The chart above shows the electromagnetic spectrum emitted by two different bodies according to Planck’s law, one shown in blue with a temperature of 288° Kelvin (15°C), and another shown in red with a temperature of 5855° K (5082°C). Why I chose these temperatures will become apparent in a moment. You can see that the peak emission frequency shifts to the left as the temperature goes up. Note that both axes are plotted on a logarithmic scale, i.e. every unit is 10 times bigger than the unit before. This is common in studying electromagnetics, because the behavior of electromagnetic waves is rarely linear.

This chart means nothing at first glance, so let’s impose something we all understand over the chart.

The green lines show the frequency of the visible light spectrum. What our eyes see as blue would be on the left-hand green line, and red on the right. You can see this effect in real life on your electric stove. As the temperature of the stove increases, the frequency of the electromagnetic infrared (IR) radiation shifts to shorter and shorter wavelengths (higher and higher frequencies). As some of the energy starts to appear in the 0.38µm region, the stove begins to glow red. This is the part of the electromagnetic spectrum that we can detect with our eyes. As the stove gets hotter and hotter, emissions shift further and further into the visible spectrum. Around 5000°C we see the body glowing white-hot. This is the area where the electromagnetic emissions caused by the temperature of the body are right in the middle of our visual detection band. If we continue to raise the temperature (a very difficult thing to do), the white will begin to turn to blue, and theoretically the intensity we see will begin to level out as the temperature goes up and the emissions are pushed into the ultraviolet spectrum that we can no longer see.

I chose to show the temperature of these two bodies because they represent the temperatures of the surface of the Earth and the surface of the sun. We see the sun as a white light in the sky because the frequency of its heat emissions is centered on the detection range of our eyes. This, of course, is because our eyes evolved under this sun to gather the optimum amount of light available. Note that while the temperature of the Earth causes it to emit electromagnetic radiation, it’s at such a low level and a low-frequency that it’s below our visual acuity.

The color of the sun is based on its surface temperature. But if we’re talking about how much of that temperature is associated with warming the Earth , we have to correct for how much energy is actually hitting the upper atmosphere of the Earth due to distance. Correcting for distance gives us the curve in blue below. Remember, this is a logarithmic vertical scale, so the difference is about 1/100,000 of the sun’s surface energy hitting the Earth.

This is an important concept to understand. The solar radiation which warms the Earth is at a different frequency than the infrared (heat) energy emitted by the Earth. When the solar energy, which is at a high frequency and high energy state, strikes an opaque object, it’s absorbed by that object. The object is excited to a higher energy state, and re-radiates the energy as infrared energy based on its own thermal curve. Typically we can expect an object on the surface of the Earth to absorb solar energy at about the 0.5µm wavelength, and re-radiate it at about 10µm wavelength. What you’re feeling as heat from direct sunlight is not the sunlight at all, but the reaction of your skin absorbing that sunlight and re-radiating it at a lower IR frequency. The hot air you feel on a sunny day has been heated by conductive transfer. The air is in contact with the surface of the Earth and is heated through conductive contact. Sunlight has very little effect on heating the air directly, because the atmosphere is mostly transparent at the frequencies in which the sun radiates. The solar radiation passes right through the atmosphere with little interaction.

An interesting side note to this is that photosynthesizing plants are cooler in sunlight than inert materials, because the solar energy absorbed is used to perform the photosynthesis chemical reaction, and is therefore not re-radiated. Photosynthesis uses CO2 and water to create complex sugars, effectively storing the solar radiation in a molecular bond, and giving off oxygen as a byproduct. When plant material is burned in a fire, or if it’s compressed over ages into coal and oil which is then burned, the solar energy stored in the sugars is released. To this effect, essentially all fossil fuels are ultimately solar energy. When you drive your car down the road, you’re releasing solar energy that hit the planet millions of years ago. Even nuclear fuels are solar energy, stored atomic power created in the supernova of a long-dead star before our sun was born.

Greenhouse Gas

CO2 is one of several different types of greenhouse gases in our atmosphere. What this means is that CO2 absorbs infrared radiation emitted by the Earth’s surface, which then heats up the CO2. As a byproduct of the CO2 heating, it also emits infrared radiation.

As the Earth’s surface absorbs sunlight, it heats up, causing it to emit infrared radiation. If there were no greenhouse gases in the atmosphere, most of the heat would be radiated back into outer space, and the surface of the Earth would be much cooler than it is now. A key point to remember is that in a thermally stable condition, the amount of energy radiated from the Earth must be equal to that absorbed by the Earth. If the Earth radiates more energy than it absorbs, it cools, if it radiates less, it heats up. Greenhouse gases in the atmosphere, including water vapor, methane, CO2 and even oxygen, absorb some of the infrared radiation from the Earth’s surface and inhibit it from radiating back into space.

When we’re discussing thermal transfer, we have to differentiate between conductive and radiative heating and cooling. Conductive temperature change occurs between objects that are in contact with one another. If there’s a temperature difference, heat energy will naturally flow from the hotter object to the cooler object. This conductive transfer also applies to gases and liquids. The warm air on a hot summer day didn’t get that way because of sunshine, which mostly passes through the air without interacting with it, but was warmed through contact with the surface of the Earth , which was heated up by absorbing the sunlight energy. Warm air then rises because it’s less dense than cool air, creating convective currents and transporting heat energy higher into the atmosphere than would be the case if the air was motionless. We preserve temperatures in a thermos bottle by surrounding them with a volume of vacuum, thereby eliminating the contact needed for conductive transfer.

Radiative transfer is the emission of electromagnetic energy, which, when absorbed by another object, heats that object. Objects that are at a higher temperature than their surroundings emit electromagnetic energy in the infrared spectrum. This is why the inside of our vacuum bottles are mirrored, to reflect infrared energy and prevent it from transferring even through the vacuum of the bottle. When discussing atmospheric warming, one has to be very careful to understand the conductive component of that warming versus the radiative component.

CO2 is a particularly effective greenhouse gas, as it makes up an almost insignificant part of our atmosphere. At 400 parts per million (ppm), it comprises 0.04% of the atmosphere, yet it’s responsible for more than 2.8% of greenhouse gas warming. The Earth emits infrared energy from a wavelength of about 4µm to 40µm. CO2 is transparent at most wavelengths, and doesn’t interact with infrared radiation at all. CO2 does absorb infrared energy from the wavelength of about 14.5µm to 15.5µm, and does so very efficiently. This warms the CO2 gas, which then warms the atmosphere through conductive heating.

Computer Modeling

Climate is a chaotic system. Small changes of input parameters can result in large changes in the final state. Computer models are designed to mimic climatic conditions, to predict climatic trends and to make “what if?” extrapolations. Of course, the earliest computer models were woefully inadequate in predictive ability, because of the vast number of contributing factors and feedback loops in a climatic system that had to be modeled by the computer. As computer models became more sophisticated, the outputs more closely resembled actual observation. Nevertheless, it needs to be understood that a computer model is a simulation of climate, using assumptions and algorithms designed to produce an output that matches observations. The assumptions and algorithms are adequate to approximate current climate observations, but one has to be cautious in assuming that a change of input conditions on the model will yield the same results as the same conditions changing in the real climate system.

To model the effect of CO2 on global temperatures, the computer models needed to simplify the effects of the chaos by using the value of a forcing factor for CO2 to apply to their equations. Using temperature measurements from the beginning of the industrial revolution to the present day, they derived a multiplier to apply to their equations that resulted in a close match to the observed data. The problem is that they assumed that all of the temperature change in that time was due to CO2 changes, completely ignoring other factors, such as changes in solar output or levels of other greenhouse gases. This is the logical fallacy of begging the question. The conclusion that CO2 changes drive global temperature changes is “proven” by equations that assume that measured temperature changes are caused by CO2 changes.

One of the assumptions made in the climate models is the contribution of CO2. The 0.04% of CO2 in our atmosphere contributes 2.8% or more of greenhouse gas warming. Without fully understanding the spectral characteristics of the CO2 contribution, it’s reasonable to assume that doubling the amount of CO2 to 0.08% would cause CO2 to contribute 5.6% or more of greenhouse gas warming. The disproportionate amount of CO2 contributions to greenhouse gas warming to the trace amounts of CO2 in the atmosphere is staggering.

This assumption seems to be corroborated by atmospheric analysis of ice core samples taken from Greenland and Antarctica. Based on the assumption that global temperature is directly affected by changes of CO2 in the atmosphere, one can analyze the ice core data and see a correlation between global temperatures and CO2 levels. This seems to confirm the hypothesis that a greater amount of CO2 will contribute more to greenhouse gas warming. One would not expect a climatologist to necessarily have a conversant knowledge in chemical spectral absorption properties, or be able to do gain and loss calculations in the electromagnetic spectrum. Without a thorough understanding of these, incorrect assumptions about how CO2 works as a greenhouse gas can be reasonably expected.

Absorption Spectrum

In the year 1802 English chemist and physicist William Wollaston passed sunlight through a very narrow slit onto a prism. This broke the sunlight up in the spectrum which he was able to view in detail on a wall 12 feet away. He was able to see a spectrum running from red, yellow, green, blue to violet. He also reported seven dark lines in the spectrum. At certain frequencies the sunlight seemed to be getting absorbed. Wollaston had no explanation for this. Twelve years later Joseph von Fraunhofer, using a much more sensitive method, mapped out 574 thin black lines in the visible band of the solar spectrum.

In 1826 John Herschel showed that when a substance is heated and the light passed through a spectroscope, each element gave off a characteristic set of bright lines of colors.

In 1849 Jean Foucault showed that the emissions lines given off by an element when heated lined up aligned perfectly with some of the absorption lines identified by Wollaston.

In 1862 Anders Jonas Ångström isolated four lines in the visible portion of the hydrogen emission spectrum, and they were later shown to match the dark lines that appeared when light was passed through a hydrogen gas sample and then refracted into a spectrum, confirming Foucault’s work.

Today we understand that these thin lines of absorptivity are as characteristic as fingerprints for identifying different molecules. These discoveries led to important advances in chemistry, understanding the atom, quantum physics and astronomy.

The CO2 Absorption Spectrum

The flaw in climatologist computer model assumptions about CO2 is that they assume that the absorptive capability of CO2 will increase proportionally to the amount of CO2 in the system. This is because they don’t consider the spectral characteristics of CO2 electromagnetic absorption.

We can see the CO2 absorption characteristics from the NIST website. To view this in context of my discussion here, change the graph settings to normal X,µm and transmittance.

So what we see here is an area of high absorption at about 4.2µm, which is near the very high-frequency end of the Earth’s infrared emissions. And then a much wider area of absorption from about 14.5 to 15.5µm. The two artifacts just below 14µm in just above 16µm appear by their symmetry to be heterodyne products caused by a preamplifier without a preselector in the measurement equipment, and are not real measurements.

Let’s plot this on the graph we’ve been looking at before:

You can see the two CO2 absorption bands here in violet, the primary band being well outside of the infrared contribution from the sun.

It’s of particular importance for us to understand what exactly is being measured in the NIST graph. This graph was achieved by analyzing the spectrum of light passed through a 10 cm path of one part CO2 mixed with two parts N2 (nitrogen), at a pressure of 600 mmHg (1 atmosphere equals 760 mmHg).

We see from the NIST data that at about 15µm, only about 30% of the IR energy is getting through. In the electromagnetic realm we measure changes of power in decibels (dB). A 70% loss of energy equates to about a 5 dB drop in power. From this, we can say that we have a 5 dB loss in a 10 cm path where the CO2 concentration is 333,333 ppm.

We can use the Beer Lambert law, A=Єbc, to calculate the needed path to get 5 dB’s of loss at the current atmospheric concentration of CO2 of 400 ppm; where A is the optical density, Є is the absorptivity, b is the path length and c is the concentration. Optical density and absorptivity are constant, so the path length and the concentration are inversely proportional. Using a concentration of 400 ppm, we calculate the necessary path length to be 83.333m (273.4 feet) for a 5dB drop in power at 15µm.

If we double the path length to 166.66 m, we get a convenient 10 dB drop in power. Electromagnetic engineers love working in increments of 3 dB and 10 dB, because it makes the calculations simple. The 10 dB drop in power means you have 1/10^th of the power after the drop that you had before. The 20 dB drop in power equates to 1/100 of the power. A 30 dB drop means 1/1000 of the power. To get a 30 dB drop in the available electromagnetic energy at 15µm due to CO2 at roughly 1 atmosphere, your path would only have to be 500m (1640 feet) long. That’s way less distance than the IR radiation from the Earth has to travel to be radiated into space.

The two primary absorptivity bands of CO2 lie in the infrared spectrum, well below that of visible light. We therefore cannot “see” these bands in a refracted spectrum without specialized equipment for detecting infrared. If we could see these with our eyes, we would see the refracted spectrum would have a black line at the point that represented the 14.5 to 15.5µm band. If we were in outer space looking at the infrared emissions from the Earth and running them through a prism, we would detect nothing between 14.5µm and 15.5µm. The infrared energy between those two wavelengths has been attenuated away to nothing. The energy has gone to heating up the CO2 which absorbed it, which then conductively heated up the surrounding atmosphere.

Proponents of the CO2-based global warming model point out that when you heat up the atmosphere, it produces infrared radiation itself, in the same bands as it was absorbed, according to Foucault. They use this to propose some sort of amplification mechanism wherein the infrared gets absorbed and re-emitted over and over, cumulatively contributing to atmospheric warming, reflecting back to the Earth and causing it to heat even more. This simplistic understanding ignores the laws of thermodynamics and the fact that the Earth/atmosphere temperature has already reached equilibrium with respect to the greenhouse gas contribution. CO2 will not radiate more infrared energy than it absorbs if it’s at the same temperature as its surroundings. It also ignores the fact that the “passing along” of photons in the direction of propagation has already been accounted for in the loss measurements such as NIST performed, and the result is still an opaque gas at those frequencies.

Given that the Earth’s radiation temperature in the infrared region is more or less fixed, adding more CO2 will not increase the atmospheric temperature in the slightest. All the available energy in the 14.5µm to 15.5µm region has already been absorbed and contributed to heating the atmosphere. The Earth’s atmosphere is effectively 100% opaque at these wavelengths. You cannot get additional energy out of the system without adding energy to it somehow. The only way that adding CO2 to the system would increase the amounts of greenhouse warming contributed by CO2 is if the initial CO2 concentration was low enough that a measurable amount of infrared radiation between 14.5µm and 15.5µm was already escaping into space, i.e. where the atmospheric opacity was less than 100%, and adding additional CO2 would increase the opacity. CO2 levels low enough for this to be the case would be too low to sustain life on planet Earth. You simply cannot become more opaque than 100%.

What would be the effect of increasing the CO2 levels? We’ve already seen the linear correlation between CO2 concentrations and the path distance necessary to completely absorb the available energy at the absorption wavelengths. Increasing CO2 concentrations will shorten that path. Effectively, this would mean that the greenhouse effect of CO2 will be concentrated at lower altitudes. The overall average temperature of a column of air will be unchanged, and any concentration of heat closer to the ground will likely be offset by convection because warmer air rises. This could have implications near the ocean of increasing evaporation, which in turn will increase convection because moist air is lighter and tends to rise. Since the CO2 contribution to global warming is less at higher altitudes when CO2 is in higher concentrations, moist convective air currents will encounter colder temperatures at lower altitudes and condense into clouds, further cooling the atmosphere through condensation and increasing the reflective surface albedo of the planet. This is a prime example of thermal feedback cycles inherent in climate science.

The Climate Record

But what of the ice core samples that show a direct correlation between CO2 levels in global temperatures? AGW advocates point at this as the smoking gun that CO2 drives global temperatures. The evidence seems to fit their understanding, where additional CO2 results in higher temperatures.

The ice core sample data seem to confirm the CO2 warming hypothesis, and no further investigation was needed. What these graphs show that isn’t explained by the CO2 warming hypothesis is why atmospheric temperatures began to fall while CO2 levels were still relatively high. CO2 levels and atmospheric temperatures seem to rise in lockstep, but CO2 levels lag declining atmospheric temperatures.

To answer this we have to consider Henry’s Law formulated by William Henry in 1803 which states: "At a constant temperature, the amount of a given gas that dissolves in a given type and volume of liquid is directly proportional to the partial pressure of that gas in equilibrium with that liquid." The key to this is constant temperature. The solubility of the gas and liquid solvent decreases as temperature increases. The oceans of the Earth are considered to have 10 times more dissolved CO2 than is contained in the atmosphere. If the temperature of the oceans increase, the amount of CO2 that they can hold in solution decreases, and the oceans must outgas the excess CO2, much the same as a bottle of soda does when you release pressure. There is no delay, and no appeal. Excess CO2 is released immediately. Conversely, when temperatures fall there is no mechanism that requires atmospheric CO2 to immediately be dissolved in the ocean. This is a slower process as the partial pressures between the CO2 in the atmosphere and the CO2 stored in the ocean slowly equalize. If our hypothesis is that ocean temperatures are directly responsible for atmospheric temperatures and CO2 levels, we would expect atmospheric temperatures and CO2 levels to rise simultaneously, and for CO2 levels to lag declining atmospheric temperatures. This is exactly what the data shows us.

Greenhouse Gases in General

CO2 gets a lot of attention from climatologists because of its disproportionate contribution as a greenhouse gas compared to its almost insignificant presence in the atmosphere. But it’s by no means the greatest contributor to the greenhouse gas effect. Water vapor is also a greenhouse gas. While it’s not nearly as efficient as CO2 and absorbing IR energy at any specific wavelength, it’s far more abundant than CO2 on average. Unlike CO2, it’s not 100% opaque at its absorption wavelengths, so increasing water vapor will result in a corresponding increase in atmospheric temperatures. Water vapor has some other important differences. Where CO2 is relatively evenly mixed throughout the atmosphere, water vapor levels vary dramatically as result of temperature and pressure differentials. Water vapor is virtually nonexistent at temperatures below freezing, and at common temperature/pressure combinations, it condenses and blocks visible sunlight from reaching the ground (clouds). The combination of opacity and reflectance of condensed water vapor is a major factor in cooling parts of the planet.

Here’s an experiment for you to do. On a typical summer day spend an evening in Charleston, South Carolina. You’ll typically notice high humidity, and when the sun goes down the temperature doesn’t change very much, it stays warm and muggy. Now take a trip out west to Tucson, Arizona. Same latitude, same amount of sunshine as Charleston gets. Same amount of CO2, generally speaking, but normally vastly less water vapor. Notice that the summer day in Tucson is much hotter than in Charleston. There is little water vapor interfering with sunlight striking the ground, heating it almost to oven-like temperatures. But the interesting thing is what happens when the sun goes down. Bring a coat, because even on a summer night it’s likely to get cold in Tucson. All that CO2 in the atmosphere doesn’t do a darn thing for keeping the air warm. The heat radiating from the Earth radiates right through the bulk of the atmosphere without inhibition, and is lost to space.

In the graph below you can see the contributions of water and CO2. But this graph doesn’t show you that the third water vapor profile varies dramatically from place to place due to differences in humidity. The CO2 graph is relatively constant worldwide, and is plainly saturated. Adding more CO2 to the system will not result in any less energy being radiated into space at those frequencies.

Response to Criticisms

My approach to explaining this through the eyes of an electromagnetic engineer is unique, but the basic concept that the CO2 absorption band is saturated isn’t. Many other AGW critics have come to the same conclusion, and of course the members of the church of AGW have developed a doctrine to answer these criticisms. One of these answers states, “Any saturation at lower levels would not change this, since it is the layers from which radiation does escape that determine the planet’s heat balance. The basic logic was neatly explained by John Tyndall back in 1862: "As a dam built across a river causes a local deepening of the stream, so our atmosphere, thrown as a barrier across the terrestrial [infrared] rays, produces a local heightening of the temperature at the Earth’s surface."”

Well, that’s an interesting and actually an apt analogy. The problem is with the assumption that CO2 is like a dam built across the stream. It’s not, because for most of the spectrum, CO2 doesn’t inhibit the stream at all. CO2 is more like a post in the middle of the stream. The water rises slightly to either side of it, because it does change the cross-section of the channel, but essentially flows around it. Make that post as tall as you want, once it breaks the surface of the water, it can’t block any more than it already does.

The other misstatement in this argument is that, “... it is the layers from which radiation does escape that determine the planet’s heat balance.” This is incorrect. The temperature of the upper layers of the atmosphere has no effect on the IR radiation if that atmosphere is transparent to the IR radiation. If the transmissivity of the atmosphere is at or near one, the IR radiation will simply pass through it with no interaction. If it were otherwise, then IR radiation simply wouldn’t propagate through the atmosphere at all. Since there is little to no water vapor at high altitudes where the atmospheric temperature is claimed to be a factor, the atmosphere is completely transparent to IR radiation across most of the spectrum.

Remember, it’s about heat balance. The energy in the CO2 absorption band is dissipated in the first few hundred meters of atmosphere above the earth, and finds its way back to the surface. Once the system is reached equilibrium, the surface of the Earth is radiating at a higher average temperature than it would be if there was no CO2. That energy is across the IR spectrum, most of which either radiates to space without any interference from CO2, or is absorbed by other greenhouse gases. Think of our post in the middle of the stream. Same amount of energy gets into space, but at a slightly higher overall temperature, since it can’t radiate in the 14.5µm to 15.5µm band.

The other argument is that the CO2 bandpass is not constant, that adding more CO2 gets deeper into what we in the electromagnetic industry call the filter skirts, effectively increasing the bandwidth of absorption. This graphic is trotted out to demonstrate:

 Of course, to most people, this graphic looks pretty impressive. Whoa! As we get more CO2, the bandpass gets wider, and we get more absorption! It never ends! Hold on a second, Hoss. Pay attention to the vertical scale. That’s a logarithmic scale, which means that every major unit is 10 times smaller than the one above it. There’s really no way to explain this if you’re not already familiar and comfortable with working logarithmically, so it’s easier just to show you.

I don’t have access to the data set they used to generate the lovely graphic above, but I do have the NIST data for the same region, so let’s use that. Using NIST’s data, here’s a similar graph to the one you see above. The area inside the red lines is currently saturated at present CO2 levels.

Now, the argument goes that the more CO2 you add to the system, the further down those skirts we’re going to be saturating, which means we’re going to be absorbing more and more energy, the more CO2 we add. The claim is that no matter how much CO2 you add, there will always be more bandwidth being saturated, so you can never encounter a condition where adding more CO2 won’t absorb any more IR energy. The graph certainly does suggest that.

But wait. The amount of energy able to be absorbed by CO2 is basically equal to the area under the curve (remember basic calculus?). If you’re going to do that, you don’t use a log scale, you use a linear scale, like this:

Exact same data. The only difference is the Y axis is plotted linearly, instead of logarithmically. Note the present CO2 levels saturate the bulk of the bandpass. Adding more CO2 will push the curve upward. Saturation (the point at which no IR radiation escapes to space at the current Earth temperature) happens at about 290 on this chart. The amount of extra absorptivity you get from the wider skirts is insignificant. Adding more CO2 is not going to significantly change how much heat is trapped.

AGW advocates claim that adding CO2 will drive the heat absorption to lower altitudes, resulting in more heat closer to the surface, increased evaporation from the oceans, and thus compounds the problem by increasing water vapor in the atmosphere, which is another and arguably more significant greenhouse gas. Yes, more CO2 will cause the heat to be trapped at lower altitudes, but this argument breaks apart very quickly, because warm air rises. Even if we assume a higher water vapor load to this rising air, it encounters cold air at lower altitudes, and the water vapor condenses to clouds, which cool the planet by reflecting a large chunk of sunlight back into space.

Conclusion

The Earth may or may not be experiencing global warming or climate change. One can reasonably argue that the Earth is constantly experiencing climate change. It’s nothing new. A variety of things may influence global temperatures, the strength of sunlight hitting the Earth , volcanic action, methane levels or pollutants and aerosols in the atmosphere. One thing that is certainly not affecting global temperatures is variations in CO2 levels. The CO2 absorption wavelengths stop absorbing linearly at concentrations of less than 1/10 of what’s currently in the atmosphere. Anyone who tries to say different needs to explain where the extra energy comes from in the 14.5µm to 15.5µm band.

Computer climate models need to be adjusted to reflect that CO2 does not act like water vapor. Above about 40 ppm, varying CO2 concentrations has little to no effect on CO2’s greenhouse contribution, because it is already absorbed all of the available IR energy in its absorption spectrum. Computer climate models also need to address gases in solution in the ocean at varying temperatures.

The climate models make the case that the effect of CO2 is based not only on the proximate warming of CO2, but also the feedback mechanisms, primary of which is an increased rate of evaporation of the ocean due to higher temperatures. Since water vapor is in itself a greenhouse gas, this evaporation is supposed to amplify the effects of additional CO2. The amplification factor is generally agreed to be three times that of warming attributable to CO2 by itself. This number is derived by the assumption that all of the observed warming in the 20^th century was a result of CO2 increases. This is an absurd assumption in the system as chaotic and complex as climate. The problem with this model is that it suggests a climate “tipping point,” which would result in runaway heating, and ignores dampening feedbacks which would tend to keep climate stable. Since in geologic history there have been times when CO2 is been many times greater than it is today, and yet no runaway condition has ever been reached, we can assume that degenerative feedback loops exist that keep global temperatures from deviating too far from the mean. The Earth is currently in a period of glaciation, and we have been privileged that our civilization has risen during one of the interglacial warm periods. The general long-term trend of the Earth’s climate is one of cooling, and this is in line with the solar output which is the ultimate source of all heat energy on earth. (Climate change in 12 minutes, the skeptics case).