There’s been a recent chain of blog posts discussing old issues regarding Michael Mann’s infamous hockey stick debate which I played some role in triggering (examples here, here and here). I’ve commented on some of them, but I’m not going to discuss any of their topics here. For this post, the arguments in those post are irrelevant.
What I want to do is see if we can establish one particularly vociferous participant, Nick Stokes, has dishonestly covered up an error he made in a figure he posted after I pointed it out.
The figure in question is the first figure of this post, displayed below:
When I first saw this image, I was confused by what appeared to be a discrepancy between it and another image displayed in the very same post. After spending a little time trying to figure things out, I posted a comment at Climate Audit saying:
Steve, I have a question. Nick Stokes has a (in my opinion ridiculous) post up which uses an emulation of your MM05 Figure 1 (his emulation was posted . The version he posts has some difference though. Notably, his emulation begins at ~.175 whereas your begins at slightly over .2, and his ends at a higher point than yours. The effect is his emulation shows the most recent part of the reconstructed series is unprecendented whereas yours shows the first 30 years surpass it.
Do you know what causes this discrepancy? My assumption right now is it’s a matter of smoothing, but I’m not sure what smoothing would produce which results.
If you read that comment, it is clear I am discussing something different than the image currently displayed in Nick Stokes’s post. The current figure starts at slightly over .2, not at the ~.175 I claimed. This causes the first 30 or so years of his graph to be higher than the most recent portions of it. It’s difficult to see how I could have simply imagined the numbers I gave. This is especially true since after posting the comment above, I began writing a comment directed at Stokes (which I hadn’t posted as I wanted to do some more testing first):
Nick Stokes, the graph you say you “think this… become a very inconvenient graph” is not the graph you claim it is. You claim to have shown the plot as an appendix in your previous post, and you repeat the same plot below this graph, but but that plot does not match the graph you lead with in this post.
In both the previous figure and your current lead, “MBH Decentered” begins at about -.1. In your current lead, Centered PCA begins at about .175, but the previous figure showed it beginning at a bit above .2. This change has a noticeable effect on the modern/past differential. In the previous figure, the first ~30 years of the reconstruction are higher than any other. In your current version, the most recent years are higher than any past temperatures.
My word is enough to accuse someone of dishonesty, but it is enough to make people look a little closer. I didn’t save a copy of the image/page I saw, and I haven’t found such in any web archives. As such, we do not have direct proof. We do, however, have compelling evidence in the form of this graph:
Which Stokes claims is his emulation of a figure created by Steve McIntyre and Ross McKitrick:
But as you can see, the bottom panels in the two figures are different. The discrepancy I claim to have seen in Stokes’s latest post is exactly the one seen in these two figures. This is true despite the fact both are shown in the same post, one after the other. Moreover, that post has another highly relevant figure:
As you can see, that figure is very similar to the one I claim Stokes has surreptitiously altered. There’s an additional line and the color scheme is different, but otherwise, they’re practically the same figure. The “MBH Decentered” line and the “Centered PCA” lines are almost identical. The only difference I can find in them is the old figure of his begins at ~.175, making it lower than the modern portion of the graph. That’s the exact difference I claim existed in the figure shown in Stokes’s recent post.
So what should we believe? Should we believe I completely imagined having seen two different versions of that figure? Should we believe that figure was always what it is now even though it contradicts previous versions of the same figure he’s posted in the past? Or should we believe Nick Stokes read my comment highlighting a discrepancy in his results, fixed the error then updated the figure without telling anyone in order to cover up his mistake?
I’m going with the latter. He commented on the same page I pointed out the discrepancy in his results. Heck, he commented in the same discussion fork. If my comment was completely delusional, I think he would have said something about it.
By the way, the title of the post I claim this deception happened in is, “What Steve McIntyre won’t show you – now.” It apparently included an image Nick Stokes won’t show you… now.