Someone nails the global warming denial claim about CO2 micron wavelength

 http://www.ces.fau.edu/nasa/module-2/how-greenhouse-effect-works.php

https://www.quora.com/How-would-you-respond-to-someone-who-says-Carbon-dioxide-can-t-warm-anything-to-more-than-80%C2%BAC-because-its-radiation-has-a-wavelength-of-15-microns

  When we plot things in terms of frequency, the CO₂ emission band at 20 THz (which corresponds to a wavelength of 15 μm) is nowhere near the peak of the emission spectrum for a black-body at -80ºC. Plotted this way, it seems totally implausible that the CO₂ emission would have an effect equivalent to that of the -80ºC black-body.

 Using such a tool, one finds that a black-body at a temperature of 67ºC has a spectral radiance with respect to frequency that peaks at a frequency corresponding to a wavelength of 15 μm.

 He shared in a comment (in relation to another answer of mine) that the Boltzmann constant, k

,[15] “literally equates the temperature imparted to a molecule by a photon to its kinetic energy divided by the constant. Once it has been absorbed, the photon ceases to exist, and the temperature imparted is all the molecule has to work with, meaning more photons can’t raise its temperature but only keep imparting the same temperature.”

(To be clear about where this narrative goes wrong, it assumes “temperature” is a concept that is meaningful at the level of the energy imparted by an individual photon. It’s not. At that level, only the total energy imparted matters.)

So, he was now apparently claiming that a photon can’t raise temperatures higher than T=E/k

where E is the photon energy and k is Boltzmann’s constant. (Photon energy is given byE=h𝞶 where h is Planck’s constant and 𝞶

is the photon frequency.)

I pointed out that this formula predicted that a 15-μm wavelength photon from CO₂, can’t raise temperatures higher than 959 Kelvin = 686ºC.

This was clearly not the desired result. So, the response came back that “the energy distributes among 5 degrees of freedom,” so you need to “divide by 5 and you’ll get -80ºC.” (Which is true to within about a degree.) He added this claim to a Quora answer that he routinely updates.

I asked where this “5 degrees of freedom” figure came from, and he offered an “explanation” that wasn’t remotely plausible. (He talked about a hypothetical type of gas that would have 5 degrees of freedom per molecule, but which couldn’t physically exist. He didn’t explain how this was supposed to relate to any real material.) It seemed clear that 5 was simply the number that was needed to generate the answer that was wanted.

Of course, regardless of what divisor one chooses, the idea of computing a “maximum temperature” for a given wavelength of photons which “can’t be exceeded no matter how many such photons arrive,” is not justified by, and is completely inconsistent with, the established and tested physical explanations of how temperature works.

Since I published the text above, the person in question has moved on to new, entirely fabricated, easily disproven, justifications for claiming that CO₂ can’t warm things.

What this episode demonstrates to me is that these claims about 15-μm radiation from CO₂ are strongly driven by “motivated reasoning.”[16] There seems to be a committed focus on finding justification for a predetermined answer, rather than a balanced effort to understand scientific reality.

The goal seems to be to find as many justifications as possible for asserting that radiation from CO₂ can’t warm things—not to determine the truth about whether radiation from CO₂ can warm things.

That’s not the way legitimate scientific analysis works.

* * *

Bottom line: There is no basis for the claim that CO₂ can’t warm things to temperatures higher than -80ºC.

 The Great Global Warming Swindle Documentary Debunked