So I did some Googling.
First, here is my post and JoNova's comment on my blog. Now mind you I have a hard time convincing myself that important people in Perth Australia stay up at night reading my blog, so maybe someone is spoofing me or is serving as proxy for JoNova's effort. Be that as it may. I am, after all, a skeptic, aren't I?
At her website, JoNova gives references for her Skeptic's Handbook.
JoNova gives this reference as the source of the bar chart on Page 8 of her Skeptic's Handbook. The same chart appears as Figure 17 in this May 2007 presentation by David Archibald.
Archibald references his own work copied here as the source of Figure 17 in the paper listed above. The very same chart appears in this paper as Figure 4. A stacked bar chart showing similar information is shown as Figure 11 in this Archibald paper.
Archibald refers in his text concerning this chart to "the MODTRANS facility maintained by the University of Chicago" which appears to be this online calculator. Reference to this was found in comments here.
An interesting rebuttal to Archibald's use of this calculator is given here by "david" who, it appears, may be Dave Archer who maintains the calculator - reference "Response" to response number 10 on this site.
So the person responsible for maintaining this calculator used by Archibald and referenced by JoNova on Page 8 of her Skeptic's Handbook claims that Archibald is deriving incorrect (deceptive) data by using an unreasonably small conversion factor in the conversion from the calculator's results to temperature change. Archer claims the error to be a factor of 10. The point is that Archer's MODTRANS calculator does not predict the results that Archibald is plotting in this chart and then crediting to MODTRANS.
So I'm thinking maybe I need to keep looking. Maybe this handbook isn't quite what it purports to be.