Guest Post by Willis Eschenbach
In three previous posts here, here, and here, I discussed problems with the paper by Shakun et al., “Global warming preceded by increasing carbon dioxide concentrations during the last deglaciation” (PDF,hereinafter S2012)
Commenters said, and reasonably so, that I had not fully addressed their claim that warming progressed from south to north. Their Figure 5a shows the trends by latitude band. It purports to show that the further north, the later the warming.
Figure 1. Figure 5a from S2012. ORIGINAL CAPTION: Figure 5 | Temperature change before increase in CO2 concentration. a, Linear temperature trends in the proxy records from 21.5–19 kyr ago (red) and 19–17.5 kyr ago (blue) averaged in 10° latitude bins with 1 sigma uncertainties.
Now, that seems pretty clear. Less blue and more red as you go up towards the north pole. What could be wrong with that? Well, as usual, nature is not that neat. When you look at it closely, it’s nowhere near as clear as that chart seems to indicate.
The first thing that’s wrong is that out of the fourteen bands with data, only five of them show a significant difference between the early trends (21.5 to 19 thousand years ago [kyr BP]) and the late trends (19 to 17.5 thousand years ago [kyr BP]). In the other nine bands, the uncertainties overlap, so we can’t even say if they are different. (The uncertainties for each band are shown as red and blue long thin lines with short vertical ends.) As a result, they are meaningless, and should not be shown.
But that’s just a symptom of the real problem, which is that there is very little data in many latitude bands, and the proxies are very different from each other.
To investigate each of the bands, I started by expressing all of the temperatures as anomalies around the average temperature from 21.5 to 17.5 kyr BP. Then I divided them by bands and graphed them. Figure 2 shows the results for the Northern Hemisphere.
Figure 2. Trends by latitude band. The background colors correspond with Figure 1, with red for 21.5 to 19 kyr BP, and blue for 19 to 17.5 kyr BP. Dark red lines are centered Gaussian averages of the individual proxies, with the data shown by the green squares.
Let me discuss these panel by panel. First, let me note an oddity—why is the early period longer than the later period? But I digress …
Panel a: Only two proxies, and one of them has a hump right at 19 kyr BP.
Panel b: Five proxies. Three have a hump right at 19 kyr BP.
Panel c: Two proxies. One is dead level, one rises during the later (blue) period.
Panel d: Three proxies, but one of them starts just before 19 kyr BP. Seriously, folks, do you think an average of these is meaningful?
Panel e: Hard to tell what’s happening here. Several of the proxies go either up or down just after 19 kyr BP.
Panel f: All trends in the blue section are about the same, except the poor proxy taking a dive right after 19 kyr BP
Panel g: Another goofy one. Right after 19 kyr BP, two of the proxies head for the sky.
Panel h: No trend before, no trend after.
Figure 3. As in Figure 2, but for the Southern Hemisphere
Again, by panel.
Panel a: Not much difference, red or blue period.
Panel b: Three proxies. Two go up at 19 kyr BP. One goes down at 19 kyr BP. Is this supposed to be meaningful?
Panel c: Three proxies. Neither the red period nor the blue period shows much.
Panel d: Two proxies. Two. One goes up after 19 kyr BP. So what?
Panel e: Here, a lot of the proxies have a low point at about 19 kyr BP … and they have a high point about 500 years before that.
Panel f: These four, all ice cores from Antarctica, agree pretty well. However, only one of them has a significant trend, and that only in the blue area.
Now, to me those results don’t mean much. Of the eighty proxies, only eight of them have a significant trend in both the red and blue periods … and that’s without adjusting for autocorrelation. The proxies show no clear pattern. They are too varied, and too few, to tell us much of anything.
Let me close with what may be a more revealing graph, dividing the globe up into 45° latitudinal bands.
Figure 4. S2012 proxies divided into four bands. Colors go from blue at the north pole, to yellow at the equator, and end up with red at the south pole.
Let me say that Panel a shows something very curious. The rise in temperature started quite early the two Greenland proxies … and timing of the others are all over the map. I can’t see how that supports any claim of late warming in the north.
BOTTOM LINE: I see no evidence in any these latitudinal bands of proxies to support the claim that the warming progressed northwards. It certainly may have done so … but these proxies are not useful for supporting that claim.
My goodness, I certainly hope that I’m done with these proxies.
w.
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Come on Mr. Eschenbach: Don’t brabble here too long about the Shakun paper.
If the Shakun paper is so full of mistakes. Just submit the rebutal to Nature magazine and ask for the chief editor’s resignation, because the peer-review process clearly failed here.
Correction: Rebuttal not rebutal.
It’s sad when all that is necessary to disprove a point is to do a full graph of the data proported to prove it.
So nobody found these issues in peer review?
jeff 5778 says:
So nobody found these issues in peer review?
That was a rhetorical question, right?
A better observation would be that these are the problems that inevitably crop up in papers when “pal” review is substituted for peer review.
jeff 5778 says:
April 11, 2012 at 6:55 am
So nobody found these issues in peer review?
_____________________________
It is not peer review it is PAL review and that is why submitting a rebuttal to Nature Magazine will be completely ignored.
You can see the “gatekeeping” in this selection of e-mails: http://wattsupwiththat.com/2012/01/06/250-plus-noteworthy-climategate-2-0-emails/
(Just do a search for gatekeeping)
The CO2 increase starts at 17.4 Kya (not between 19.0 Kya and 17.5 Kya) so the temperature increases lagging CO2 have to start after the blue section, not inside it. I’m not sure what Shakun what trying to show with the blue versus red Trend C/Kyr-1.
Over the last century, GISS data support the claim that the Arctic is especially prone to warming.
Trouble is, the data has been fiddled, with mid-20th century temperatures depressed by sleight of hand: http://endisnighnot.blogspot.com/2012/03/giss-strange-anomalies.html
You left off the Sarc tag. Admittedly he COULD submit a rebuttal, but given history, what chance would there be that it would be accepted and printed by Nature? And if, as is likely, it were published in another journal, you know that the response would be, a) why was it refused by Nature and b) everyone knows journal Y is owned by big oil.
The fact is that until there’s a cleansing of the Augean stables of the CAGW crowd, blogs like Climate Audit and WUWT ARE the journals of record.
All too often lately ‘peer-review’ of papers is done by indentured servants (graduate students or post-docs), in the names of their masters (research professors whose reputations warrant their selection as reviewing ‘peers’). The professors themselves are far too busy (usually re-reading papers those same students have written which will eventually be published with the professor’s name as lead author) to review papers written primarily by another professor’s students.
Thanks Willis for your excellent review of this paper.
My goodness, I’m certainly hope that I’m done with these proxies.
=======================
Me too! LOL
..cause I’m hoping you’ll tackle the latest retroactive sea level adjustments
I am sure the grant justified the conclusions, or the conclusions justified the grant. Some of these guys must must have business cards stating, “Will research for money. Your results guaranteed.”
So nobody found these issues in peer review?
It’s not surprising that they didn’t. A reviewer doesn’t actually generally try to replicate and extend the results — no time and that’s as much work as the original researcher did if not more. If they had some reason to doubt the results or the quality of the work they might do this sort of thing, but otherwise one generally assumes the competence and honesty of the author and looks to see if their arguments are sound and clear, not necessarily if they are correct.
rgb
Unfortunately, I don’t have time right now to look at this, so I will just raise the question:
I am wondering how they derived their (bar) graph.
My *guess* is that the N hemisphere data is dominated by some form of proxy which is not present, or only rarely, in the S hemisphere.
Throw out, or weight proxies to get an even N-S distribution of proxies, and I bet the skew disappears.
“jeff 5778 says:
April 11, 2012 at 6:55 am
So nobody found these issues in peer review?”
——————————————————————
Of course not.
What you thought Peer Review checked the science? Then you have been fooled by the paper mills. Peer Review does no such thing.
Thanks Willis. Any further examination may be labeled necroscopy!
“So nobody found these issues in peer review?”
Well its a bit like Nelson at Copenhagen, what’s at issue is the motivation to look and then to see the signal……
It is time to promote a new higher quality mark than peer reviewed: willis reviewed
Faster to.
Jeff,
If this paper was submitted for no other reason than to set the scene prior to Rio then no one will be looking for any errors in the paper. It is submitted for no other reason than to support the green advocacy that will come out of Rio.
Mailman
Will well done and thank you.
It’s sad that in the real word 2+2 = 4 – simple I know but to the Shakun’s of the world they are so desperate that they will torture a fact’s so it suits their own predetermined outcome.
Even though it is obviously a lie, a manipulation and a fraud. But they don’t release these so called Study’s for us (Sceptics) they produce them for the grants, travel and rewards of alarmism. Their fiction is a Frankenstein of fiction blended none to skilfully with science = an inconvenient D grade movie! They produce this garbage for the sheeple, the converted, the blind and the stupid, who also have the power and the purse strings to keep this hoax going.
So: To a Sceptics and 99.99999 % of the worlds population, 2+2 = 4
To Shakun’s and the other nefarious actors 2+2 = can be 5 or any number they choose.
Such is the state of climate science to day!
Robbie may believe the Shakun paper is a “dead horse” by now with WUWT multi-coverage, but until “professors of climate or earth science” like Jeremy Shakun at both Harvard U and Columbia U stand down from their spurious claims, they deserve heaps and heaps of exposure and ridicule. We already know that Nature Magazine is a rag for CAGW; there will be no peer review worthy of the name coming from Nature. The focus should be on our universities, the professors of pseudo-science therefrom, and the negligent education budding scientists have received since the 1990s and are receiving today. Every baseless or questionable claim and/or method should given the fine-tooth-comb treatment and no one does it like WUWT.
Also think of the millions (billions) of dollars (taxpayer, mostly) going to spurious “science” and be grateful for these attempts to correct the balance.
Thanks to Anthony, Willis, and others we have science, especially earth and climate science, to read, consider, discuss, and debate.
My observation of peer review is that the reviewers mainly look to make sure any and all of their own papers even remotely related to the topic are cited in the text.
“If they had some reason to doubt the results or the quality of the work they might do this sort of thing, but otherwise one generally assumes the competence and honesty of the author and looks to see if their arguments are sound and clear, not necessarily if they are correct.”
My question was only partly rhetorical. Maybe I am naive. Willis makes it look so easy. I would be embarrassed if I were the author(s).
Thanks for the replies.
Gives new meaning to an old term “Shakun Bake” when applied to “climate science” diastrophism. Good job, Willis, on this and prior expose`s. Most incisive!