Atmospheric IR - Where Does 15 Micron IR Come From?


Why do we care? - a key component of the Global Warming Greenhouse Effect theory is accepting that atmospheric carbon dioxide absorbs the IR radiated from Earth and then somehow returns it or holds it as a warm "blanket" that prevents the heat from getting into space. It is proven fact that carbon dioxide can indeed absorb long wave infrared as this is the basis for spectroscopic analysis of the gas but it has also been shown that it can only absorb three wavelengths of the full range of long wave IR wavelengths (0 to 25 u) supposedly being radiated up from Earth at night. 

The three wavelengths are 2.3, 4.5 and 15 microns. All individual electromagnetic wavelengths require an emitter to give off IR when it reaches specific temperatures, each wavelength requiring a different emitter temperature to create that specific wavelength. With 2.3 u it is 1800 F only found in volcanoes; with 4.5 u it is 800 F also not found naturally on Earth; and with 15 u it is -80 C, extremely cold condition perhaps found in Antartica. 

So, under normal conditions an Earth emitting IR at its average temperature of 288 K simply shouldn't emit IR at any one of these three critical wavelengths and therefore the C02 in the atmosphere would not receive any of the critical wavelengths that it could absorb. Therefore the whole theory falls apart. It can't absorb and hold heat because there is no "substrate" for it to feed on (ie. a supply of appropriate wavelengths). 

So, why do we insist that long wave IR is absorbed by atmospheric carbon dioxide? In particular, ignoring the IR given off by lava flows or hot volcanic chambers, why is there 15 u IR coming off Earth in significant quantities that it can be absorbed by C02 and reversed to cause the greenhouse based global warming effect?

There is a way to explain its presence in the outgoing range of IR energies - but it requires some fundamental changes in the way we think of one physic's primary (theoretical) tools - the Black Body. 

What is a Black Body? 

Basically, a black body is an object that can warm itself up through the absorption of the full range of electromagnetic energy wavelengths and is also capable of emitting all ranges of electromagnetic energy, particularly the infrared range spanning 0 to 25 microns. 

This ability to emit a range of infrared energy wavelengths goes against the original basic laws of electromagnetic wave creation that says only one wavelength is generated for each unit of temperature considered. A black body is assigned a temperature which supposedly depends upon the "quantity" of photon based heat being held within its interior. This heat is supposedly present as range of electromagnetic energies / wavelengths  that "bounce around" inside the body as a heterogenous blend that is then released as range of wavelengths rather than just one wavelength that coincides with the original assigned black body temperature. 

Make sense? Not really, does it? In order to create a situation that explains one phenomenon (specific temperature / range of wavelengths) physicists break the rule that creates another phenomenon (specific temperature / single wavelength).  How can we explain this?

Cliff's Theory of Black Body Radiation

In what might look like an act of extreme arrogance, I respectfully present a theory of how a black body of a specific temperature can spontaneously emit IR radiation over the full potential long wave IR range of 0 to 25 microns. Perhaps I'm right or most probably I'm wrong, but what I do achieve with my unqualified theory is a model that is easy to understand and more importantly MAKES SENSE because it doesn't break the rules in order to achieve a desired endpoint as described above.

The Spectral Range of Earth as a Black Body.

In a Macro sense, Earth is considered as a single Black Body with a black body temperature of 288 K. The single temperature in the purist sense dictates that Earth should only radiate upwards one wavelength of electromagnetic long wave IR energy - that wavelength being ???? microns. But this does not happen and the commonly accepted model is that Earth radiates up a range of IR radiation. This range of wavelengths forms a graph called a radiation spectrum which can be calculated from Planck's formula and presented as shown below:

So, IN THEORY, this is the radiation spectrum emitted by Earth at a temperature of 288 K over a range of 50 microns IF EARTH IS CONSIDERED TO BE A SINGLE BLACK BODY.

IT COULD ALSO BE CONSIDERED TO BE A TEMPERATURE CURVE. - since each wavelength corresponds to a particular emission temperature, we could equate the wavelength axis to a temperature value as well. This says that EARTH HAS A RANGE OF TEMPERATURES AT ANY GIVEN MOMENT IN TIME THAT SPANS A MASSIVE TEMPERATURE DIFFERENCE RANGING FROM THOUSANDS OF DEGREES TO ALMOST 0 KELVIN.

Convert to Kelvin? - add 273 to deg. C
Convert to Kelvin? - add 273 to deg. C


What is required is to equate the emittance of a particular wavelength of IR to a "new" temperature of the black body. For example, when the black body is 17 C it will be  emitting 10 um IR. When it changes to - 80 C then it will emit 15 um.  and so on...  

Does this happen? Who knows. Especially because the black body is not really a real thing. It's an invention made by physicists to simplify things. In order to make it "work" we need to invent a mechanism that would allow our black body to emit all wavelengths without violating the basic laws saying it must be a specific temperature in order to emit a specific wavelength.

Ta Da !! Introducing Cliff's Mechanism of Blackbody Emissions:

Capacitor analogy - in electronics there is a key component that is used extensively to capture electrical energy, increase its content of that energy up to a certain predetermined level, and then expel it in a single "rush" back into the circuitry. In this way it stops electrical flow, pauses it for a given level of time and then restarts it as an electrical pulse before doing the same thing all over again. By altering its internal construction and controlling the voltage delivered to it we end up with a timed pulse - the basis of the famous 555 timer used in pretty much every circuit ever produced.

A black body can be likened to the capacitor. It is capable of absorbing electromagnetic energy of all wavelengths and in doing so "warming itself up" to a certain maximum level. This maximum level of internal energy is defined by the temperature of the black body (such as saying Earth's black body temperature is 288 K). A fully charged black body is then capable of emitting its internal energy to a colder receiver such as the ultimate receiver - outer space. It does so by discharging long wave infrared energy with wavelengths that correspond to its given peak temperature.

Classical theory seems to ignore the original basic Wiens laws that say only a specific wavelength can be produced for any given specific temperature. Instead it says that a black body emits a range of wavelengths even though it has only one temperature. Planck shows how curves such as above can be formed with a "peak" that corresponds to the given temperature, but really fails to explain why the black body emits other wavelengths that according to basic Wiens laws can't be produced at the black body temperature. It just "happens" ...

How can it do this and not violate the laws? Well, if you consider the black body as a capacitor and if you accept that it unloads its internal electrical energy in an "instantaneous" but still "linear" fashion you can see why you get a range of wavelengths instead of just one wavelength. If the black body starts emitting appropriate wavelength IR at its body temperature it instantly starts to deplete its internal store of energy.

Since its original temperature is determined by the quantity of energy it contained,  this depletion of energy has the effect of "cooling" the black body and causing its temperature to drop accordingly. The next "batch" of emitted energy then comes out of the black body at a longer wavelength consistent with being generated at a lower temperature. The process continues all the way down the temperature scale to 0 Kelvin where there is no more internal energy to emit. At that point the black body is free to "recharge" with new energy from its external source, whatever that might be. 

The result - a range of wavelengths, not a single wavelength. A Planck curve instead of a single spike of high energy at a very specific wavelength. No laws broken. All laws satisfied.  A win - win situation. 

But then why doesn't Earth cool off to absolute zero and then rewarm to 288 K?

This micro process cannot be slow or else we would have measured it by now. It must be "instantaneous" while still remaining "linear" in order to make any sense. On a macro scale we must accept that a massive black body is composed of an infinite number of micro black bodies all following this pattern and all doing so at different times than each other. The net effect is the macro black body appears to be only one temperature, even though internally its micro-capacitors are losing temperature as they linearly discharge to zero and then regain temperature as they recharge back to the observed macro black body temperature.