Do you have what it takes to be a climate auditor? Try the following fun test and find out. And at the same time, you can’t help but learn something about the fine art of argumentation from charts as practiced by the master himself, Steve McIntyre, and refined in his most devoted media outlet, the U.K. based Mail on Sunday.

Here is the chart that is held to epitomize the “trick” to “hide the decline”: figure 2-21 from the IPCC ‘s Third Assessment Report, showing key temperature reconstructions.

Now take a look at the following two not-quite-identical versions of the 1400-2000 portion of this chart (this allows us to show these at full viewing resolution as originally published).

#1:

#2:

Perhaps the difference is not jumping out at you. If so, here’s a hint: focus on the green reconstruction, namely the one described as:

—–Briffa, 2000 (tree-ring density, summer only, extra-tropical).

And pay special attention to the end of the curve (yes, both versions end in1960, but there is a difference between them nonetheless).

Still not sure? Even after clicking on each to show it at 200% zoom? Well, then, read on.

To review, Steve McIntyre objected to the termination of the Briffa reconstruction in 1960, and criticized IPCC authors Chris Folland and Michael Mann for supposedly applying pressure on Briffa to change his reconstruction so as to not “dilute the message”.

But the climate science auditor was particularly outraged by one supposedly nefarious aspect of the “trick”:

The hiding of the decline was made particularly artful because the potentially dangling 1960 endpoint of the Briffa reconstruction was hidden under other lines in the spaghetti graph as shown in the following blow-up:

Or as McIntyre put it in his presentation at University of Toronto’s Trinity College on March 10, 2010:

IPCC section author Mann resolved the conundrum. He chopped off the inconvenient portion of the Briffa tree ring data – the portion where it goes down – and tucked the end point under other data, giving a rhetorical impression of consistency.

So the claim is that “hiding the decline” was in part accomplished by “artfully” putting the Briffa curve behind the others.

And the difference between the two versions I showed is simply this: #1 is the original chart, while #2 is identical, except the end of the Briffa reconstruction has been shown on top of the other series. I’ll show exactly how this very slight difference was accomplished later on, but for now let’s explore the implications.

Personally I can’t tell the difference even at double magnification – and I even know it’s there. That should bring home what should have been obvious from the start. Mcintyre’s demonstration of the “artful” effect of “tucking in” the Briffa reconstruction behind the others, requires what appears to be a blow up of at least 8x magnification. Thus, this supposed manipulation of the graph can not have any practical effect of deception, as only a couple of pixels are affected and the difference is imperceptible under normal viewing.

For most reasonable people, that fact alone would settle the matter. But there’s more to this than meets the eye (or rather even less).

First, let’s consider the five curves shown (four reconstructions from three different studies, plus the instrumental record.

—– Mann et al, 1998 (full hemisphere) —– Mann et al, 1998 (30N-70N latitude band) —– Jones et al, 1998 (summer, extra-tropical emphasis) —– Briffa, 2000 ( tree-ring density, summer, extra-tropical) —– Instrumental (annual mean, hemisphere)

There is a certain logic to this order; the first three reconstructions are from 1000 on, Briffa’s from 1400 and the instrumental record only from 1850. The drawing order reflects this, with the Mann reconstructions on top followed by Jones et al and then Briffa. The instrumental curve is on the bottom, behind all the reconstructions.

Now suppose the drawing order had been reversed. Then the Briffa reconstruction would be on top of the others. But that would also leave the instrumental curve on top of all the reconstructions, including Briffa’s. Undoubtedly, the self-appointed auditors would have yelled foul at that too. Scientists just can’t win.

Now let’s move on to another important aspect of climate science auditing, media coverage.

In this case, few media outlets were convinced by McIntyre’s logic. But David Rose of the U.K. Mail on Sunday was an effusive exception. Here is how Rose described the manipulation of the IPCC:



However, the full context of that ‘trick’ email, as shown by a new and until now unreported analysis by the Canadian climate statistician Steve McIntyre, is extremely troubling. Derived from close examination of some of the thousands of other leaked emails, he says it suggests the ‘trick’ undermines not only the CRU but the IPCC. … On the hockey stick graph, [Briffa’s] line is abruptly terminated – but the end of the line is obscured by the other lines.

Take a look at the accompanying figure used to illustrate the point:

Clearly the above image is much clearer than McIntyre’s “blowup”, which appears to have been a simple low resolution zoom of the original graphic. So let’s consider a multiple choice version of the obvious question: How did the Mail generate this chart? Presumably the answer is one of these choices:

(a) The chart was a cleaned-up digitized version of McIntyre’s “blowup”.

(b) The chart was created from a magnification of the original IPCC chart.

(c) The chart was fabricated from scratch in an undisclosed manner, possibly as an attempted emulation from the original unsmoothed data. [Updated: May 12]

There’s a hint to the correct answer in the previous discussion of drawing order. In fact, there are several clear differences between the Mail figure and the real one:

The Mail version has the pink Jones et al curve on top of the Mann et al curves.

The Mail version shows the green Briffa curve going behind the pink Jones et al curve, which abuts against the red instrumental curve without any gap.

And, perhaps most importantly, the end of the green Briffa curve is completely hidden in the Mail’s version, but not in the real IPCC figure.

You can confirm the above points in the “blowup” of the real figure:

And what’s that in the gap between the other curves? Why, it’s the corner end of the Briffa reconstruction, clear as day.

Earlier, I promised to show how I created the slightly modified chart above. I simply took the PDF of chapter 2, viewed figure 2-21 at 24x magnification, and drew in the end of the Briffa curve on top of the pink Jones and black Mann reconstructions. Like so:

Like I said before, you can see the difference pretty clearly at 24x zoom. But at normal viewing resolution, not so much.

So in summary, we have a nonsensical accusation of “artful” manipulation of a key graph. And we have a fake “blowup” from the Mail on Sunday that contains important differences with the real figure.

But that’s not quite the end of it.

McIntyre has been complaining bitterly that the Oxburgh inquiry looking into possible research misconduct at the Climate Research Unit of East Anglia University got it all wrong.

So, in addition to not taking any evidence from CRU critics or targets, the terms of reference for the execrable Oxburgh “inquiry” diverted its attention away from articles that actually were at issue to other articles that had actually been used as source material to identify the trick in the first place.

Excerpt from IPCC 2001 “trick” spaghetti graph.

Recently, McIntyre wrote a post extolling the spoof video “Hide the decline II” (surely I’m not the only one to notice that McIntyre has dropped any pretense of examining any actual science). In the comments, McIntyre laid it on the line:

Steve: The fact that Hide the Decline II contains better analysis of the trick than either the Oxburgh Committee or Willis Committee is a testament to the incredible low level of analysis that took place in either committee. They have no one but themselves to blame for that.

Would-be paleoclimatologist Craig Loehle chimed in:

It is interesting that comedians can sometimes understand complex issues better than learned societies and eminent panels.

Here is a screenshot from the video, showing that “better analysis”:

Yep, that’s right – it’s the fake “blowup” graph from the Mail on Sunday.

[Update, May 13:

Here is a graph of UAH satellite record, from the opening sequence of Hide the Decline II video. It’s a perfect example of a “trick” to “hide the incline”, as the cherrypicked 1998 peak and June 2009 trough are emphasized, while the overall increase over the period (0.13C per decade) is obscured.

Even though this new edition of the video was released very recently, the UAH record is shown as of nearly a year ago, using the cherrypicked low end point of June 2009. Since then UAH has risen to near record values of over +0.6C anomaly for January through March 2010, while April 2010 stood at 0.5C. No doubt other examples of this sort of compelling “analysis” praised by McIntyre could also be found.

Returning to the IPCC spaghetti graph to sum up, here is a side by side comparison showing the end point of the green Briffa recontruction. Let’s review all the differences identified so far between the real IPCC graph and the fake Mail version.

The Mail version has the pink Jones et al curve on top of the Mann et al curves.

The Mail version shows the green Briffa curve going behind the pink Jones et al curve, which abuts against the red instrumental curve without any gap.

The Mail version appears to terminate the pink Jones curve too early.

The Mail version shows the black Mann et al curve above the end of the green Briffa curve; thus the Briffa end point appears to be behind the red instrumental curve , which is incorrect.

, which is incorrect. The Mail version completely obscures the peak of the green Briffa curve.

And, perhaps most importantly, the end of the green Briffa curve is completely hidden in the fake Mail’s version, but not in the real IPCC figure.

The Mail blow up appears to be derived from the Mail’s own version of Fig. 2-21, seen below.

The Mail article does not explain the provenance of this figure. It seems likely that is based on an emulation of the original figure, possibly using the original reconstruction data. However, as we have seen, the Mail version differs from the real figure in several important respects at the crucial end point.

To repeat: The Daily Mail should now explain completely the provenance of the fake version of the graph, and also explain why they substituted this version for the real thing.

Perhaps an “audit” of the data, code and methodology would be in order. ]

[(End update).]

So parting questions are these: Why should anyone take Steve McIntyre seriously? And how long will it be before responsible journalists and commentators expose his baseless “analysis” for the nonsense that it is?

Stay tuned for part 2: The emails that McIntyre forgot to show.