p.s. ...should I post this without checking the facts first; without looking at the link to that logarithmic graph?
Should I rant about how anyone can take a real graph of something and then just re-label it to suit thier own opinion (or add their own trend lines, or conflate data from two different graphs, etc., etc.)?
Let's go look. Up to now i've only been looking on my Kindle -and can't follow links.
Hey! There's no citation at all. Is this just some made up graph? I went through that whole unpublished "scientifically denialist" technical paper,
http://www.mikechurch.com/joomla/images/stories/global_NOT_warming/Falsification_of_CO2.pdfthinking it must come from there; but no... not there. FromWhere?
Thanks for the link to another of those wacky sites, much like the Creationist/ID'er sites, that dazzle folks with scientific information (much of it valid) and then draw completely unwarranted conclusions to so obviously suite their own agenda.
--> end p.s.
& here's a link to some relevant surfings:
http://www.scienceagogo.com/forum/ubbthreads.php?ubb=showflat&Number=26454#Post26454===
p.p.s. I see my memory of the graph was wrong, but I'm confident that my points below are still valid....I haven't looked yet, but I'm betting someone has taken a graph showing the extinction of IR in an absorbing medium (and then relabeled it as the heating potential of IR -or was it CO2).
I'll have to look at the graph again (and the source!).
ummm....
Several times along this thread, I thought it was important to try and describe how energy flows in the atmosphere. It's quite a story; an action tale, set in a landscape bordering on the quantum and macroscopic worlds.
[put in explanation here, or the rc link]
...yea, ...since your source is MikeChurch, I'm just gonna include this neat clip from a realclimate blog.
http://www.realclimate.org/index.php/archives/2008/04/back-to-the-future/feed/
For all practical purposes the energy from a photon at 15 microns is absorbed in a CO2 molecule’s vibration. This energy is more than twice the kinetic energy of a molecule’s translation at a nominal 300K, and does not affect the temperature, other than from the likely trivial momentum transfer just mentioned. By equipartition quantum probabilities it will strongly want to relax This relaxation is predominately transferring energy to another atmospheric molecule’s translation via collision, at other than very low pressure (density). This does raise the atmosphere’s temperature. It can, though unlikely, transfer to its own translation; however this becomes trivial since the molecule will still quickly relax its new found translation energy again via collision. It can also re-emit a photon instead, the probability of which increases as pressure decreases (among other factors). Conversely, a CO2 can sometimes collide with another molecule, pick up some kinetic energy and immediately relaxing via photon emission, transiting through vibration, and provide a net cooling of the atmosphere
Some of my calculations as a reference (and a check if anyone is so inclined):
The energy of a 15micron photon is 1.325×10^-20 joules; its momentum is 4.4×10^-29 [you’d think by now physicists would have come up with momentum units; I suggest OOMPHS!]
The kinetic energy of a CO2 molecule at 300K is 6.214×10^-21joules (3742 joules for a mol); its momentum is 3.0×10^-23; its velocity (or the average velocity for a mol) is 412.5 m/sec.
One photon’s energy going into one molecule’s translation will raise its temperature from 300K to 630K; the mol’s avg. temp would increase to 300.038K.
The standard relaxation process has a complex formula of probabilities. Of interest is the vibration to translation transfers usually require a large number of collisions before occurring. 10,000 to 100,000 is often quoted, but that is usually at high temperatures (500-1000K) where the molecule is more “comfortable” with its vibration. At atmospheric 200-300K (and normal pressure) it is less : 100-10,000 I would guess (haven’t done the cumbersome math), and more likely to make the transfer. The lower rotation energy takes 5-100 collisions to make a translation transfer and is highly likely — H2O to N2 or O2, e.g. Going the other direction — translation to vibration to emission — I would think (no math again) at low temp and pressure, e.g. stratosphere, somewhere around the 10,000-100,000 collisions range is more the normal and not as likely to occur.
...
In the lower atmosphere there are a lot of CO2 molecules being blasted with thermal radiation from the surface of the earth. They will lose their absorbed vibrational energy to the translational energy of the air molecules through collisions which preserve momentum but transfer energy.
In other words, the surface air will be radiatively heated, just as food is heated in a microwave oven.
Cheers, Alastair.
...
http://www.realclimate.org/index.php/archives/2008/04/back-to-the-future/#comment-85606
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So, the important point to realize that while this graph is true, the origin of that IR can be anywhere in the atmosphere; its origin is not relegated to the earth's surface.I think this is an accurate characterization of the weird quantum side of the story.
Any molecule of CO2 can spontaneously emit IR (say ~14.7 microns) simply by colliding with a higher temperature molecule of N2 or O2. It doesn't even need to be a collision of a specific energy, as long as it's over a certain lower limit; with the bulk of the energy being converted into the IR emission and the remainder adding on to the momentum and vibration of the CO2 molecule.
...and of course, the reverse can also happen... after absorbing some IR. It's not as if there is a particular quantum of 14.7 IR that leaves earth and you can track it's journey. Well, you can; but you have to follow all its many transitions, from potential energy to kinetic energy, and back again while being added into the sea of energy that is out there and then split off again at some other level (part of some higher energy quantum -or as some, or several, lower energy quanta).
More simplistically, you could envision a particular quantum of 14.7 IR being absorbed a foot above the surface
...and then being emitted, to then be absorbed another foot away, higher above the ground. Now it's two feet above the ground as it gets emitted again, only to be absorbed a foot away (at 3 feet above the ground)... etc., etc....
CO2 could be seen as a series of relay stations, ferrying a quantum of IR up to the higher reaches of the atmosphere where it can finally radiate away (without hitting something and raising its temperature... as it may do all the way up through those thicker layers of the atmosphere).
That extinction graph is a snapshot of what one quantum does, on average, in an absorbing medium (each medium having its own extinction coefficient). It's not a measure of how a quantum will heat the air, but of how easily a quantum gets absorbed.
After it gets absorbed is the story of how energy is stored and transmitted and heat flows.
