CO2’s role in climate hard to prove

earthI am often asked how I could question the greenhouse explanation of global warming, when so many climate scientists believe the theory is sound. One possible explanation is I am not a climate scientist, so I may look at the physics of the atmosphere with more emphasis on the physics. The whole idea of greenhouse-gas warming is based on the “observation” that planets with atmospheres are 33 degrees C warmer than planets without atmospheres.

Now, planets satisfying these criteria are not exactly jumping out of the sky. This would mean to me that this atmospheric-effect theory never actually has been experimentally tested according to the scientific method. This may be acceptable to 97 percent of climate scientists, but it tends to make me itch.

Let’s say, however, that there is something to it. Having established that our atmosphere warms the planet by 33 degrees C (notice, I didn’t say how), what gases are the major components of today’s atmosphere? There is nitrogen (78 percent by volume), oxygen (21 percent), water vapor (about 0.2 percent; it varies), and carbon dioxide (0.04 percent by volume). Other gases are at much lower concentrations and will not be considered.

My first inclination on how this works is by an insulating-blanket effect. Oxygen and nitrogen gases near the surface absorb heat energy from the warm surface by colliding with it during the day, and then hold on to this energy by passing it back and forth through molecular collisions as they slowly rise to higher altitudes. During the night, the gases near the surface pass the energy back to the surface, which then radiates it as infrared light to space. Increasing CO2 levels should have little effect on this mechanism, since the concentration is so low. Since warming of the planet seems to be nearer to the surface, this is a plausible, but untested, theory.

A second possibility is the greenhouse effect. Oxygen and nitrogen gases are not greenhouse gases, meaning they cannot absorb infrared light. So we are left with water vapor and CO2. Now, greenhouse gases can’t just absorb any arbitrary IR radiation. Like a radio or TV, they must be tuned to a specific wavelength of light. Carbon dioxide only can absorb Earth’s IR radiation in a narrow band of wavelengths centered around 15 micrometers. But the Earth does not emit a lot of radiation at 15 micrometers. According to infrared astronomers, Earth radiates strongly in a band that peaks around 10 micrometers (infrared astronomers refer to this as N-band radiation). CO2 does not absorb strongly in the N-band, because 15-micrometer radiation falls in the tail of this band at very low intensity. It does not take a lot of CO2 in the atmosphere to absorb essentially 100 percent of the 15 micrometer radiation in this band. Adding more CO2 to the atmosphere once this radiation is gone has no effect.

Colder areas of Earth’s surface (minus 80 degrees C, Antarctica temperatures) do shift Earth’s radiation toward 15 micrometers where CO2 absorbs more strongly, but these cold regions of the Earth’s surface are very small compared with the warmer areas near the equator.

Which of these theories is correct, and could there be others? Who knows, but until any are tested experimentally, they all are just chalk dust.

James Barrante of Cheshire is a retired college professor of physical chemistry.

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    Al Shelton

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    @James: Well said. Your reference to radio wavelength is good. A radio antenna does not “trap” all of the radio waves going past it. The station one tunes in receives a signal the rest go on. Neither does the 15micron band for CO2 trap all the infrared radiation going past it. Only the minute amount of IR at that wave length, with all the remaining IR going out to space [at the speed of light btw]
    For some experimental papers on GHG Effect go here:
    http://principia-scientific.org/publications/Experiment_on_Greenhouse_Effect.pdf
    There is more info at this site if you care to read it.

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    Al Shelton

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    One more thing……….
    I suggest that one refer to EMR not light.
    Light is one part of EMR [Electro-Magnetic Radiation]
    eg: “a radio station must be tuned to a particular wavelength of EMR. [not light].

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    John Wilder

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    CO2 can’t be a “greenhouse gas” because it does not rise up into the atmosphere. Google the specific gravity of CO2 and it will take you to numerous scientific sites all stating that it is 1.52 or literally 152% heavier than air. IT SINKS TO THE GROUND WHEN RELEASED. This is why they put it into fire extinguishers.

    The theory sort of posits that CO2 rises into the atmosphere and acts like thermal pane windows to retard thermal transfer. The problem with that analogy is that it falls on its face when you examine the facts. A thermal pane window consists of two or 3 panes of sealed window glass with the dead air space is filled with an inert heavier than air gas of Argon or Krpton. In order to effectuate thermal resistance you have to fill those windows with a MINIMUM of 80% gas. The problem with CO2 if you accept the scientists numbers it is only 400PPM which the fractional equivalent is 40/100,000ths of 1% no where near the 80% required to cause thermal resistance.

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    Amber

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    John Wilder… that being the case how then can they try and sell the fallacy that ” earth has a fever” ? What you say seems to make sense however the whole con had some scientific plausibility for even the bought and paid for portion of the scientific community .

    Where is the scientific disconnect ?

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      Robert

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      The big failing was using the term “greenhouse” in the first place. The mechanism of warming in a greenhouse is due to a blocking of convection. Warm air cannot rise and escape because there is literally a glass roof preventing it.

      Nothing in the atmosphere behaves that way, first off regardless of whether CO2 will rise or fall, it will be a well mixed gas in the atmosphere. It isn’t a “thin layer high up in the atmosphere” like Kerry tried to create the image of.

      This being the case, for the claimed effect at the levels it exists in the atmosphere to be true then we would have to see extremely large effects in experiments with pure CO2 at 100% concentrations. We don’t see the corresponding effects at the magnitude that would be necessary to even begin claiming CO2 would do what they claim at the ppm concentrations we are talking about.

      Part of the disconnect as well is there are a lot of people in fields which rely in some form or another on physics but in which the bare minimum of physics is covered. And to the extent that it is covered a fair portion of what is being taught is incorrect.

      Tallblokes is a good site if you want to lurk in the shadows and see some people who do understand physics have some good discussions.

      Main problem? Scientists aren’t engineers, their “theories” don’t have to actually do anything. If engineers tried to build bridges or design aircraft using the same piss poor understanding of physics, fluid dynamics, gas laws, etc. as climate scientists do they’d be sue’d out of their job and have their credentials revoked.

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        Gator

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        As I have pointed out before a greenhouse requires the intervention off man to keep it from overheating, and this is one reason alarmists are so in love with the term.

        I call it the “Outhouse Effect”. It’s FOS, has to be moved regularly, and stinks.

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