2011-02-03 08:58:04CO2 is just a trace gas!
John Hartz
John Hartz

On US media sites, the climate denier bloggers have been hammering away on this theme during the past couple of weeks. 

My response to these posts has included a quote from and reference to SkS rebuttal, “How do we know more CO2 is causing warming?”, Advanced version, Sep 9, 2010.

Given that there are a number of SkS rebuttals with CO2 in their titles, am I using the best one to rebute this particular meme?

2011-02-03 09:38:04
Paul D


Ask them if they know which gases respond to long wave (infra red) radiation and which are transparent to it.
Those that respond are the ones that count. Those that are transparent can not be counted as being of equal importance, hence greenhouse gases are not trace gases as far as long wave radiation is concerned.

That would be my 'simple' riposte (could be worded better), although of course the issue is more complex.

Or you could just use this link:


2011-02-03 09:51:01
Julian Brimelow

Badger, do they deny the importance of another trace gas....ozone?  What about the CFCs which have even lower concentrations, and take note of their impact on the ozone layer.  Do they deny that regulating CFCs was required?  Probably, they probably think that was "hoax" too.



2011-02-03 11:16:20Ville & Albatross
John Hartz
John Hartz

Thanks for the feedback and suggestions.

Many of the posts that I encounter are worded very similar to the skeptic's argument articulated on the webpage that Ville provided the link to. They tend not to get into a dsicussion of other trace gases.

Ville: What is the status of the webpage that you provided the link to? Is it a "blog" post that is available to the public, or is it a draft rebuttal in its embryonic stage?


2011-02-03 11:37:27The Science of Doom's Rebuttal
John Hartz
John Hartz

The Science of Doom's website contains an eight part article under the heading, "CO2 – An Insignificant Trace Gas?" Part One, by itself, is longer than any advanced rebuttal posted on SkS to date.


Before I refer anyone to the Science of Doom's website, i would like to know what the SkS experts think of it. It appers to be authored by a single individual who is well grounded in the theoretical side of how the climate system works. Am I correct?  

BTW, The person behind the Scince of Doom screen uses a significant number of grahics in his posts.  I would encourage SkS authors to peruse his posts to see if they contain graphics that would be useful to include in an SkS post.   

2011-02-03 12:20:59


I looked at just a part of SoD's presentation on trace gas (there are 8 parts). In general, I think it's OK; but I thought there were a couple of points he was missing: In particular, on the question of Beer's law and saturation, which I don't really believe apply in the GHE. Maybe he fixes it up in a later part, I can't be sure right now.

My thoughts on this are in some thread that I intend to write up someday real soon (when I have pulled out of this mess at work). I think it was either in the General Chat or the Blog Post group.

2011-02-03 13:29:48Earlier thread on CO2 as a trace gas


Here it is:


2011-02-03 15:56:33nealjking
John Hartz
John Hartz

I skimmed through the discussion thread that you provided. a very interesing discussion, especially the metaphors.

Perhaps one way to rectify the seeming contradiction between the concept of "CO2 is just a trace gas" and the impact that adding 100 plus ppm of CO2 to the atmaosphere has on the greenhouse effect would be to plot how many molecules of CO2 are in the troposphere at different levels of ppm. 

I suggest this because the average person intuitively grasps that a problem is truly a big deal when it is expressed in big numbers. For example, once the US national debt exceeded $1 trillion, the average person started to pay attention to it.  

BTW, How many molecules of CO2 are in a cubic meter of atmosphere at 385 ppm? How many cubic meters of atmosphere are in the troposphere?

2011-02-03 17:35:31The challenge of the trace gas rebuttal
John Cook

Is there are so many ways you could argue this. I really like the metaphor of holding an election in a town of 1000 people where only 10 people vote. That kind of metaphor would work well in the basic version. But there are several ways to come at this so I think all 3 rebuttals probably need to be written together - probably publish the intermediate as the blog post with a green box at the bottom with some text pointing to the other versions and talking them up a bit to get people to go visit the other versions).
2011-02-03 20:30:38
Paul D


I used pie charts:


It's very simplified, but makes an obvious point.
It probably needs expanding, but then you probably lose part of the audience and then gain a new one (scientists or those well versed).

2011-02-03 20:37:05
Paul D

I like SoD. Who ever it is, is really brave to do all that publicly.
However it is aimed at a level that has a small audience, I can just about follow it.
I have occasionally posted some comments, but often I am out of my depth at least at this point in time.
He is currently doing a good series on the greenhouse effect, complete with a simple model.

Actually I think I might raise a new thread here on a subject that was triggered by SoDs greenhouse effect series.

2011-02-03 21:00:25further clarification needed


The pie charts are useful, but more needs to be said for the explanation:

"However, as discussed previously, this hides the issue of the response many compound gases (such as Carbon Dioxide) have to Infra Red radiation. So if you were an Infra Red electromagnetic wave, what components of the atmosphere would you be interested in?"

=> "However, this presentation of the raw molecular population misses the fact that different types of molecules interact differently with light of different frequencies. For an important band of light in the infrared, with wavelength around 15 microns, CO2 is by far the most interactive: If I were a 15-micron IR photon trying to escape the atmosphere, I would be most worried about the CO2 molecules. The next pie chart gives an idea of the weighted importance of the different varieties of molecules to me, reflecting their affinities and their numbers. (Sorry about the anthropomorphizing!)"

I don't know how you generated the pie chart, but basically the two numbers being compared should be in proportion to the product of the relative population with the 15-micron absorption cross-section for each of the two (H2O and CO2).  

(Actually, the relative population depends on altitude, which leads to another story. But for a start, you could take the relative populations at sea-level; and then later talk about high altitudes (100 km) where H2O vanishes.)

The link to "as discussed previously" does not seem to work. 

2011-02-03 21:18:06
Paul D


Neal: Aaaarrrrghhh. Don't bring altitude into it! Most of my audience just want to know who the managers of the local shops are, or when a new shop is opening!

I'll check the links. I changed the domain name (due to original poor spelling) so there maybe a few that need fixing still.
(Added: all links on the pages are fixed)

I'll have a think about the other issues you raised. I did produce it early last year when climegate was still raging, so I am open to suggestions for improvement.