Reductio ad mannium

The new article by Rahmstorf and Mann (see RC here) has been criticized at WUWT (here here) for making claims about Atlantic Ocean currents based on proxies, rather than measurements. (Also at Judy’s here)   But it’s worse, much worse than we thought.

Rahmstorf and Mann’s results are not based on proxies for Atlantic current velocity, but on a network consisting of contaminated Tiljander sediments (upside-down or not), Graybill’s  stripbark bristlecone chronologies, Briffa MXD series truncated to hide-the-decline and hundreds of nondescript tree ring series statistically indistinguishable from white noise. In other words, they used the same much-criticized proxy network as Mann et al 2008-9. It’s hard to understand why anyone would seriously believe (let alone publish in peer reviewed literature) that Atlantic ocean currents could be reconstructed by such dreck, but Rahmstorf et al 2015 stands as evidence to the contrary.

After so much controversy about Mann’s prior use of contaminated data, it defies credulity that he and Rahmstorf have done so once again.

And when the National Research Council panel recommended in 2006 that stripbark bristlecone chronogies be “avoided” in temperature reconstructions, they can scarcely have contemplated (let alone, endorsed) their use in reconstruction of Atlantic ocean currents.

Seemingly leaving no stone unturned, the Rahmstorf and Mann dataset even truncates the Briffa MXD chronologies in 1960, thereby hiding the decline (see here for a discussion of MXD truncation in Mann et al 2008 in September 2008, long before we learned from Climategate emails that they were using a trick to “hide the decline”)

In 2002, even Keith Briffa was frustrated enough by the Mann et al 1998 reconstruction to observe:

I am sick to death of Mann stating his reconstruction represents the tropical area just because it contains a few (poorly temperature representative ) tropical series. He is just as capable of regressing these data again any other “target” series , such as the increasing trend of self-opinionated verbage he has produced over the last few years , and … (better say no more)

But at least the network that Briffa complained about contained a “few poorly temperature representative” tropical series.  Rahmstorf et al 2015 dispensed with even that meager precaution by purporting to reconstruct Atlantic ocean currents without using any proxies purporting to directly measure Atlantic ocean current.

What is one to say of a climate science field which permits such practices to continue unchecked?  Should one borrow Andrew Weaver’s words and say:

They let these random diatribes of absolute, incorrect nonsense get published. They’re not able to determine if what’s being said is correct or not, or whether it’s just absolute balderdash.

Also see Arthur Smith here and Atte Korhola here on prior use of contaminated sediments. The reputable climate science community should collectively cringe with embarrassment.

Whatever may or may not be happening with the Atlantic Meridional Overturning Current (AMOC), one thing that you can take to the bank (or insane asylum, as appropriate): contaminated Finnish lake sediments, strip bark bristlecone pines and the hundreds of nondescript Mann 2008-9 tree ring series do not contain any useful information on the past history of the AMOC.

Only one thing can be surmised from Rahmstorf and Mann’s claim that the Mann et al 2008-9 network can be used to reconstruct not just NH temperature, but also SH temperatures and now Atlantic Meridional Overturning Circulation: using Mannian RegEM with the Mann et al 2008-9 network of 1209 “proxies”, one can probably “reconstruct” almost anything.  Are you interested in “reconstructing” the medieval Dow Jones Index?  Or medieval NFL attendance?

Reduction ad mannium.

Postscript:  unsurprisingly, Rahmstorf et al has many interesting booby traps.  As homework questions. (1) why is the most recent value of the gyre reconstruction shown in Rahmstorf Figure 3 (middle panel) ends in approximately 1995, when the underlying gridded reconstruction of Mann et al 2009 goes to 2006.   (2) why are the reconstructions only shown back to AD900, when the underlying gridded reconstruction of Mann et al 2009 begins in AD500.


  1. kim
    Posted Mar 25, 2015 at 3:33 PM | Permalink

    Hey! That wasn’t even a minute.

    • kim
      Posted Mar 25, 2015 at 3:46 PM | Permalink

      Over at Judy’s I said Steve must have left British Columboa in his Peugeot 403 Hemi!

      • Fred Harwood
        Posted Mar 25, 2015 at 5:46 PM | Permalink


  2. Brandon Shollenberger
    Posted Mar 25, 2015 at 3:50 PM | Permalink

    For homework problem (2), isn’t the answer just that’s how far back the reconstruction was “skillful” for (under some weird Mannian definition of “skillful”)?

  3. AndyL
    Posted Mar 25, 2015 at 4:04 PM | Permalink

    If he had removed Tiljander, this would have been an admission of error, which Mann would be loath to make. Mann’s habit has been never to admit a mistake. Remember how he repeated the Rain in Maine.

  4. DBD
    Posted Mar 25, 2015 at 4:12 PM | Permalink

    This is a little early for an April Fools post:) Unbelievable

    • kim
      Posted Mar 25, 2015 at 4:15 PM | Permalink

      I said on the other thread that he must have been double down dared to try this trick and he was foolish enough to take the dare. Worse, it was he who dared himself.

      • Brian H
        Posted Mar 29, 2015 at 2:37 AM | Permalink

        Doubling-down is about all he’s capable of.

  5. Hoi Polloi
    Posted Mar 25, 2015 at 4:14 PM | Permalink

    Is “dreck” another word for sediment?

    • seanbrady
      Posted Mar 27, 2015 at 11:02 AM | Permalink

      Ha ha! If there were this much dreck in Lake Kotajärvi they wouldn’t even have needed the bridge.

  6. Frank Cook
    Posted Mar 25, 2015 at 4:21 PM | Permalink

    It makes quite good sense to me.

    This is a perfectly reasonable exemplar of “Mannian teleconnection” in action.

  7. Posted Mar 25, 2015 at 5:05 PM | Permalink

    Interestingly, Manns AMOC wiggles line up reasonably well with the 10Be solar proxy post 1100AD. A variable he (and many others) don’t seem to any longer consider.

  8. Posted Mar 25, 2015 at 5:21 PM | Permalink

    Don, not this time, in Germany no less. The paper has been ‘trashed’ by no less than FAZ (equivalent to the New York Times) and Der Spiegel (loosely equivalent to Time magazine.) I have read both auf Deutsch. Gosselin has a summary in English. The German has more compelling idiomatic nuances.
    The times, they are achangin.

    • Brad Keyes
      Posted Mar 26, 2015 at 4:34 AM | Permalink

      “I have read both auf Deutsch… The German has more compelling idiomatic nuances.”

      LOL, awesome. Well, don’t leave us in suspense! Did they use rud words?

  9. Posted Mar 25, 2015 at 5:27 PM | Permalink

    Steve, that they repeat the same mistakes without acknowledging the prior underlying peer reviewed errors is just stunning. Surely this approaches academic misconduct?

  10. Posted Mar 25, 2015 at 5:30 PM | Permalink

    I’ve uncovered a portion of the SI for the paper. I think I can see from where they are coming.

    • Streetcred
      Posted Mar 27, 2015 at 2:10 AM | Permalink

      You found the ‘coil’ on the footpath ?

  11. Posted Mar 25, 2015 at 5:38 PM | Permalink

    Worldwide non-commercial space launches correlate nicely with US Sociology doctorates awarded.

    Possibly Mann is on to something within climate modeling, exposing a deeper meaning within the Universe.
    ( )

  12. Brian
    Posted Mar 25, 2015 at 5:44 PM | Permalink

    Steve, you need to be a little more direct . . . you know . . . just come right out and say what you think.

    • Fred Harwood
      Posted Mar 25, 2015 at 5:48 PM | Permalink


  13. Posted Mar 25, 2015 at 5:54 PM | Permalink

    And when the National Research Council panel recommended in 2006 that stripbark bristlecone chronogies be “avoided” in temperature reconstructions, they can scarcely have contemplated (let alone, endorsed) their use in reconstruction of Atlantic ocean currents.

    Ah, you weren’t reading between the lines. As Weaver & Burke would immediately have realised they were only saying temperature reconstructions. Never has respect for a NRC panel been more er, extensive.

  14. Posted Mar 25, 2015 at 6:22 PM | Permalink

    Well done. Your article is devastating as usual.

  15. Posted Mar 25, 2015 at 6:34 PM | Permalink

    Mann down!

    But Chris Money and thus the Washington Post have taken the bait.

    The Mann cabal may not be much good at science but between this sort of rubbish and “97‰” they certainly hold the attention of a scientifically illiterate and incurious mainstream media.

    • Posted Mar 25, 2015 at 6:40 PM | Permalink

      The ridicule we’re rightly applying here will eventually reach the ears of such scribblers in the MSM. At some point they’ll realise they’ve been gulled and it won’t be pretty.

      • Posted Mar 25, 2015 at 7:16 PM | Permalink

        I beg to differ, in that I don’t think even Mooney realises how lousy this latest work is.

      • Don Monfort
        Posted Mar 25, 2015 at 7:44 PM | Permalink

        Do you think he will ever find out/believe how lousy it is? What will he do, if he does? Even in the unlikely event this POS gets retracted, I doubt you will see many in the mainstream media giving the comeuppance any significant attention. The paper has already served its purpose. Expect a lot more like it leading up to the big Paris junket.

      • Posted Mar 25, 2015 at 8:28 PM | Permalink

        I won’t predict what one person will do with the understanding they’ve been had. But in an extreme case like this, given the skills of Steyn and others, a number will realise it and some will have the courage to rethink. At which point, as I said, it won’t be pretty. That presupposes you’re right about others.

      • michael hart
        Posted Mar 25, 2015 at 9:52 PM | Permalink

        Perhaps he’s trying to provoke Steyn into saying something that could be used in court?

    • Gerald Machnee
      Posted Mar 25, 2015 at 9:54 PM | Permalink

      No, Mann Overboard – this is the ocean!

  16. thingadonta
    Posted Mar 25, 2015 at 6:42 PM | Permalink

    Obviously they think their scientific position protects them from simply making things up.

    • Don Monfort
      Posted Mar 25, 2015 at 6:58 PM | Permalink

      They are very likely going to get away with it again. Who’s gonna stop em?

    • Ron Graf
      Posted Mar 26, 2015 at 12:50 AM | Permalink

      I saw this article blast on Yahoo News feed from VOX 2 days ago. They start off the article reminding everyone of the movie “The Day After Tomorrow,” and then say this is not quite that.

      I think this qualifies for one of those methods written about a few posts back, sticking an outrageous claim into the mind with the headline or first line and them disclaim it. here it is:

  17. MikeN
    Posted Mar 25, 2015 at 6:44 PM | Permalink

    >to reconstruct not just NH temperature, but also SH temperatures and now Atlantic Meridional Overturning Circulation: using Mannian RegEM with the Mann et al 2008-9 network of 1209 “proxies”, one can probably “reconstruct” almost anything. Are you interested in “reconstructing” the medieval Dow Jones Index? Or medieval NFL attendance?

    The us of ‘random diatribe’ is acceptable if the target is picked at random.

  18. observa
    Posted Mar 25, 2015 at 7:00 PM | Permalink

    “Why are the reconstructions only shown back to AD900, when the underlying gridded reconstruction of Mann et al 2009 begins in AD500?”

    Out of respect for AD900 when Zwentibold, King of Lutherans dies in battle at 29? Alfred the Great, English monarch, dies?

    These are religious and crusading men of authority you might recall.

    • Watchman
      Posted Mar 26, 2015 at 7:00 AM | Permalink

      Alfred died in 899 (the source for the date is proven to be out by one year) – so your logic is probably correct, as actually checking and correcting data would not have anything to do with the logic of this paper which is clearly just to keep the pressure on about climate change…

  19. observa
    Posted Mar 25, 2015 at 7:34 PM | Permalink

    Well you didn’t really expect them to honour a mathematician did you?
    Forerunner to those pesky statisticians interfering in the size of their pi.

    • David Jay
      Posted Mar 25, 2015 at 11:50 PM | Permalink

      Wait, so the size of pi is fixed? Don’t tell the capitalists!

  20. Joe
    Posted Mar 25, 2015 at 8:25 PM | Permalink

    At this point I believe Mann has gone beyond delusional.

    From his recent presentations that all the models are eerily matching realty by presenting Hansen’s scenerio C as the proof that all the climate models are accurate in the predictions,
    That the amo pdo only have a cooling cycle
    to that nobel price he won.

  21. Jeff Alberts
    Posted Mar 25, 2015 at 8:32 PM | Permalink

    Wow. Appropriately, the ad shown at the end of the post, for me at least, showed a picture of a skunk, nothing more. Climate Science ran over it, and now it’s stuck in the undercarriage of their flower power VW microbus, stinking up the place.

  22. Duster
    Posted Mar 25, 2015 at 8:41 PM | Permalink

    “…Zwentibold, King of Lutherans…” AD 900???? Talk about proxy errors!

    There WERE no Lutherans in AD 900. Martin Luther was born 1483 and died in 1546.
    His 95 theses were tacked up in 1517.

    • David Jay
      Posted Mar 25, 2015 at 11:55 PM | Permalink

      He is a liberal Lutheran – He doesn’t accept absolutes (in dating)

    • Posted Mar 26, 2015 at 4:48 AM | Permalink

      Wikipedia tells that the fabulously monickered Zwentibold was ruler of the Kingdom of Lotharingia – doesn’t seem like too much of a stretch that inhabitants would be styled “Lutherans” in some language / dialect.

      I am currently constructing a proof of this by regressing BCP growth onto Wikipedia references, just a bit of parameter tweaking to do/

      • dave
        Posted Mar 26, 2015 at 2:49 PM | Permalink

        Truncated historical records after 899 onto your valuable work sean2k and found using the first letters of each paragraph nailed to the wittenburg door that while travelling on a plain in Europe Luther then planted a forest on a peninsula called Lamay. He baptised his first young man under a tree there and the rest of his followers then died due to a lack of water.

    • observa
      Posted Mar 28, 2015 at 9:00 AM | Permalink

      Never let the fuzzy facts of Zwentibold get in the way of a good mythology about the roots of Lotharingia Lutherans or some such, or Catholics claiming him as their martyr-
      but perhaps it was all about sympathy for a crumbling kingdom well past its use by date. Can’t you people ever empathise with and contextualise these important historical signposts?

  23. bmcburney
    Posted Mar 25, 2015 at 8:50 PM | Permalink

    “The reputable climate science community should collectively cringe with embarrassment.”

    The situation seems like a natural experiment. Someone should be keeping track of who cringes and who patiently explains that BCPs and lake varves really are teleconnected to Ocean currents. Will Gavin cringe or will he defend the idea? Phil? Keith? Hans? Ben? How bad would it have to be before these guys actually cringed?

  24. stevefitzpatrick
    Posted Mar 25, 2015 at 9:23 PM | Permalink

    “The reputable climate science community should collectively cringe with embarrassment.”

    I rather suspect they will circle the wagons in defense of this bizarre effort. Remember that Rahmstorf has several published ‘predictions’ of 1+ meter sea level rise by 2100, yet continues to publish nonsense in high impact journals. The acceptance of this most recent silly effort by the ‘community’ will add ever more weight to the view that the whole field is focused on public policy, not on science. Truly sad.

    • sue
      Posted Mar 25, 2015 at 11:15 PM | Permalink

      I agree SteveF. Mann is not the lead author of this, but is pimping it on twitter, at the same time seems to be walking back from it. Interesting that Delworth who worked with Mann on earlier papers has been quoted as questioning these results in a news article. Rahmstorf authored the RC post and is the lead author of the “paper”. I’ve heard it has been trashed in Germany newspapers. But the ‘community’ will circle the wagons… It’s very sad.

  25. Follow the Money
    Posted Mar 25, 2015 at 11:24 PM | Permalink

    Regarding questions about “fig. 3”, what “instrumental” series is shown? Look at the last twenty, then fifty years. We are cooling now? That is “Mannian”??

  26. sue
    Posted Mar 25, 2015 at 11:42 PM | Permalink

    Mann making the controversy about something else. Watch the pea…

    • observa
      Posted Mar 28, 2015 at 9:23 AM | Permalink

      “Some critics have tried to make hay over a previous article from last year by URI Graduate School of Oceanography scientist Tom Rossby.. [Tom incidentally is the son of the great meteorologist Carl-Gustaf Rossby of “Rossby wave” fame: He also happens to be a friend…]”

      What pea sue? As Admiral Nelson would say placing the telescope to his eye..

  27. David Young
    Posted Mar 25, 2015 at 11:48 PM | Permalink

    Are we sure that the reconstruction was not just of temperature and then the models were used to get the circulation? That might be a fig leaf they will bring out and perhaps we should carefully think about it.

    • David Jay
      Posted Mar 25, 2015 at 11:59 PM | Permalink

      I’m pretty sure that Steve has read and parsed the paper before commenting – that’s been his way at least since I started reading CA in about 2008.

  28. AntonyIndia
    Posted Mar 26, 2015 at 1:08 AM | Permalink

    The figure 4. shown in the Realclimate’s “What’s going on in the North Atlantic?” to illustrate this cold bubble proves nothing: using the same input data except for the Time Interval (year) one gets equally cold bubbles in from 1920 or 1922 and from 1946 to 1950 or warm bubbles from 2005 to 2007 on the same location.

  29. AntonyIndia
    Posted Mar 26, 2015 at 2:58 AM | Permalink

    Is RealClimate morphing into Unreal Tournament?

  30. AntonyIndia
    Posted Mar 26, 2015 at 3:11 AM | Permalink

    Even Nature-“climate change” took over half a year to process this article: Received 14 July 2014; Accepted 28 January 2015; Published online 23 March 2015. Even there it must have been a hot potato although COP 15 is on the horizon.

  31. Brad Keyes
    Posted Mar 26, 2015 at 3:26 AM | Permalink


    “The reputable climate science community should collectively cringe with embarrassment.”

    You’ll be glad to know, from a quick survey of this thread, that’s pretty much what they’re doing.😀

    Thanks for taking out the Storf’s stercoraceous trash with your customary wit and efficiency.

    “Dreck” is quite a euphemism for such literary night soil! Your composting of it is sure to go down in the annals of reductiones ad abturdum.

    • Brad Keyes
      Posted Mar 26, 2015 at 4:27 AM | Permalink

      And what is it with people called Stefan, Stephan and Steffen?

      • stevefitzpatrick
        Posted Mar 26, 2015 at 7:13 AM | Permalink

        I don’t know, but I am a Stephen, and I think the paper is rubbish.

        • Brad Keyes
          Posted Mar 26, 2015 at 7:22 AM | Permalink

          Ah, but that’s a voiced fricative so you’re safe ;-D

    • Frank
      Posted Mar 26, 2015 at 9:54 AM | Permalink

      Ed Hawkins:”But, there are a number of very large caveats in the Rahmstorf et al. study which have been largely ignored in the media coverage of it.”.

      • DB Wood
        Posted Mar 27, 2015 at 7:51 AM | Permalink

        I was reading through Ed Hawkins comments though (forgive me for going off topic, but I went to his comments and study through here and then returned back)

        “It is not clear whether excess winter deaths are due to the cold weather or flu – see the linked discussion in the ‘See Also’ section of the blog post. It is not as straightforward as you assume. We have adapted to cold weather a lot already, with better home insulation etc.”

        Basically earlier he attributes a .1% increase in 2003 mortality to temperature increase (pretty much insinuates solely too), then comes back down and when there was a 23 pct increase in mortality during temperature decrease which he was referencing here, he says it is not clear whether excess winter deaths are due to the cold weather or flu.

        I don’t understand why people seem to desire to find a single point of blame for such events, an increase in deaths during an increased temperature season could involve hundreds of variables, how would you attribute it to “just heat”, same with a winter decrease in temperature, not to mention when it is so statistically insignificant (like the 40k deaths he mentions during 2k3). Here this same person I have to say when confronted with extra deaths during a winter season, says well it may have been the flu (to which sure I understand perhaps the flu was at work as well), however, it seems exceedingly disingenuous to attribute extra deaths solely to heat, while ignoring other compounding factors, yet when it comes to winter, the compounding factors are key.

        I feel like all of this “mainstream” science has gone down the toilet, so much predictive analysis rests on a dismissal of so many contributing factors. Although perhaps it is me pervading in my own ignorance. How do kids even learn anything now when they are told to pay attention to this study or this model, and ignore if the predictive results are wrong, because science changes.

  32. Posted Mar 26, 2015 at 4:34 AM | Permalink

    The RealClimate post by Rahmstorf admits that predictions of a slowing AMOC have been made many times. Their justification for publishing the paper relies entirely upon the usefulness of the proxies.

    What is new is that we have used proxy reconstructions of large-scale surface temperature (Mann et al, 2009) … to estimate the circulation (AMOC) intensity over the entire last 1100 years (Fig. 3). This shows that despite the substantial uncertainties in the proxy reconstruction, the weakness of the flow after 1975 is unique in more than a thousand years, with at least 99 per cent probability. This strongly suggests that the weak overturning is not due to natural variability but rather a result of global warming.

    Any non-credulous observer might wonder how they produced a greater-than-99 per cent probability despite “substantial uncertainties” in temperature proxy reconstructions?

    To validate the proxy reconstructions of temperature we use standard techniques developed during the past two decades in the paleoclimate community.

    Oh, well then. Carry on.

    • Posted Mar 26, 2015 at 4:56 AM | Permalink

      Carry On Forever

    • David Jay
      Posted Mar 26, 2015 at 7:05 AM | Permalink

      Wow – unique in 1000 years with a 99% probability.

      Strip bark and Tiljander – is there anything they can’t do?

      • Posted Mar 26, 2015 at 7:58 AM | Permalink

        Mann’s proxy reconstruction is the ShamWow! of climatology. Use it for any task! As seen on TV! …and in Nature, and in Science, and….

  33. David A
    Posted Mar 26, 2015 at 4:52 AM | Permalink

    Steven M, this appears to be incomprehensible Naclov anti-logic

    (In honor of Leonard Nemoy, Naclov is Volcan backward, meaning anything completely devoid of logic, causing the brains processing center to cramp into complete paralysis of repetitive saying “this does not compute”)

    If these are the proxies there must be some attempt in the paper to connect these to AMOC currents. I consider you a brave man to venture into such realms, but if you do can you spare us the effort and tell us how this attempt to relate such unconnected observations is justified?

  34. mpainter
    Posted Mar 26, 2015 at 5:29 AM | Permalink

    This type of science can viewed as a “separator”. It will be interesting to see who in the climate community swallows this rubbish with its ” tipping” points, if anyone.

    • Posted Mar 26, 2015 at 5:33 AM | Permalink

      Mann’s entire corpus acts as a separator. The next few weeks will, indeed, be interesting.

      • kim
        Posted Mar 26, 2015 at 6:20 AM | Permalink

        This should be comprehensively and publicly debunked and rejected else any further cooling be linked in the public’s mind with man’s effect. Then we would be well and truly through the looking glass.

        I’m counting on the sensible. Still counting.

        • Fred Harwood
          Posted Mar 26, 2015 at 10:48 AM | Permalink

          “It’s easier to fool people than to convince them they have been fooled.” – Mark Twain

  35. kch
    Posted Mar 26, 2015 at 6:59 AM | Permalink

    I’m puzzled about something, and hoping that someone can steer me in the right direction on this.

    In R/M 2015, they seem to describe the construction of their AMOC index this way: they take the NH (land+ocean) time series anomaly derived in Mann et al 2008, and subtract that from the subpolar gyre (SST) time series anomaly derived from Mann et al 2009.

    Now, Mann et al 2009 shows a time series for the entire AMO area, but this does not match the R/M 2015 subpolar gyre series. I have to assume that this is because the subpolar gyre series is from a smaller region, but is derived from the spatial reconstruction of Mann et al 2009.

    Am I wrong on this? If so, how?

    But if I have read this correctly, it then appears to me that the derived subpolar gyre series covers a geographic region that contains *zero* proxy data (as can be clearly seen in figure 2 of Mann et al 2009).

    Again, am I wrong? How and where?

    Steve: yes, the gyre region is taken from Mann 2009, but is much smaller than the AMO region. The Mann et al 2009 dataset does not contain any proxies from the gyre region – and only a couple of ocean proxies in total. There is considerable ocean proxy data, just not in the Mann 2009 dataset. Ocean data is interesting, but has its own separate problems. High resolution data is relatively scarce in the gyre as defined. But interestingly the coral series shown by Mann is offshore eastern Canada. CA readers will recall that I recently wrote about high-resolution alkenone data offshore Newfoundland: this is just as relevant for the purpose as the coral data, and is longer.

    • kch
      Posted Mar 26, 2015 at 1:04 PM | Permalink

      Steve – thanks for the reply.

      So, they create their AMOC index by subtracting one paper’s proxy derived temperature series from a completely interpolated temperature series derived from different proxies in a different paper that used a different method.

      They then claim, with high confidence no less (p>0.99!), that this says something important about the AMOC.

      On the face of it, this would seem to be a ridiculous overstatement. There are so many layers of assumption built into this process that it looks to me as though they have, in fact, demonstrated nothing solid.

      I would actually appreciate it it I could be pointed to a good defense of this methodology, as I can’t help feeling that there *has* to be more to it that I’m seeing.

      Steve:it’s ridiculous but you don’t have it exactly right. The networks and methodology of Mann et al 2008 and Mann et al 2009 are substantially the same. It would have made more sense to use the NH series from Mann 2009, but not too much turns on this issue. The larger question is using contaminated data, stripbark bristlecones etc and the crazy overfitting of the methodology itself.

      • kch
        Posted Mar 26, 2015 at 5:46 PM | Permalink

        Ah, right. Thanks for that clarification, I should have remembered that from past reading. I do still wonder why the use of the NH series from 2008 versus using that from 2009. As you say, it would make more sense. I can’t really see the point of doing it their way, aside from giving an extra citation. [Also, I still can’t buy the justification in the SI for using Mann et al 2009 for the subpolar gyre reconstruction, rather than using the actual data from the area that was available.]

        I will say that my major questions still are on the methodology used in R/M 2015. The “crazy overfitting”, the compounding uncertainties and (to me) unfounded assumptions make me wary of seeing that the method is actually accomplishing anything.

        The underlying issues with the proxies are also major, but I would think that that is – at this point – flogging a very tired horse. Nothing at this point will make the defenders of the Team’s reconstructions change their mind on them, nor are those defenders likely to be able to successfully argue against the problems laid out over the years here and elsewhere.

        It is useful – and amusing – to point out that once again the same old tired stick, complete with the same old tired proxies, is being hauled out to play a prominent role in yet another “worst in a thousand years” meme, but for now I’d rather try to figure out if the method can be justified. If it can, then re-open the proxy discussion to try and get a real picture, but if it can’t be justified, well, the proxies don’t much matter.

        • MikeN
          Posted Mar 26, 2015 at 9:25 PM | Permalink

          I think several of the defenders have changed their mind, such as William Connolley, Arthur Smith, Ari Jokimaki, but some may not be willing to admit it.

  36. stevefitzpatrick
    Posted Mar 26, 2015 at 7:28 AM | Permalink

    It seems to me that the goal of the work is to once again publish something in the peer reviewed litchurchur which says (yet again) ‘unprecedented in at least a thousand years’, which green activists can then use to pressure politicians; the poor politicians are either too dumb to know that such claims are dreck, or are green activists themselves. If you look at Rahmsorf’s earlier publications, they are mostly devoid of serious analysis, and focused on the same ‘impending catastrophe’ meme. It’s all political.

    • Posted Mar 26, 2015 at 11:09 PM | Permalink

      To hit a jackpot, you have to get the president to make a tweet.

  37. angech2014
    Posted Mar 26, 2015 at 7:29 AM | Permalink

    Perhaps we go about things the wrong way when we get upset over minor scientific digressions.
    A nice letter to the editor encouraging people to read about the Professor’s new work on Atlantic currents with the help of pine trees in California and Finnish swamps over the last millennium might get more attention drawn to the paper.
    Then debunk it.

  38. stan
    Posted Mar 26, 2015 at 7:36 AM | Permalink

    It’s even worse than we thought.

  39. Gary
    Posted Mar 26, 2015 at 7:45 AM | Permalink

    Perhaps it’s time for the Journal of Irreproducible Results to publish a special issues of papers showing everything the Mann et al 2008-9 proxy network can explain.

    • AJ
      Posted Mar 26, 2015 at 9:34 PM | Permalink

      Unfortunately they are all too reproducible. That is, give a close network of pal scientists the same questionable data and questionable methods, and they will produce the same questionable results. I believe that Wegman’s paper touched on this subject.

  40. MikeN
    Posted Mar 26, 2015 at 8:41 AM | Permalink

  41. Cicero666
    Posted Mar 26, 2015 at 8:53 AM | Permalink

    It is very simple, this is ‘science’ for the true believers only. Steve etc are in the pay of big oil, The 2006 report about Mann was again due to everyone involved in questioning his work being funded by big oil, etc etc Try and argue with some of them on-line and they have a completely twisted view of reality. They really believe it because it has become a religion. The final step to insanity is that it appears in Skeptical science website.

    • richardswarthout
      Posted Mar 26, 2015 at 11:04 AM | Permalink


      Game over. Time to vacate the bleachers and let the clean-up crew take over.


  42. A. Scott
    Posted Mar 26, 2015 at 12:45 PM | Permalink

    A paper written in search/anticipation of a media headline … where have we heard that before?

  43. Brian R
    Posted Mar 26, 2015 at 1:41 PM | Permalink

    I think Mann’s next trick with his data is to reconstruct the first billion years after the big bang and show how modern day CO2 levels influenced the expansion. I’m sure he’ll figure out a way to do it….and get it published.

  44. Posted Mar 26, 2015 at 7:42 PM | Permalink

    From Ed Hawkins at his blog: “there are a number of very large caveats in the Rahmstorf et al. study which have been largely ignored in the media coverage of it.”

    To which Robert Way added: “That’s putting it rather kindly :P”

    • Posted Mar 26, 2015 at 7:43 PM | Permalink

      Dang it, forgot the closing tag.😦

      • kim
        Posted Mar 26, 2015 at 9:42 PM | Permalink

        Kindly caveat
        And truck it to the ashcan.
        Alley cats, Alert!

        • Jimmy Haigh
          Posted Mar 27, 2015 at 12:48 AM | Permalink

          Caveats? The press don’t care about caveats. All they need is a headline.

  45. William Larson
    Posted Mar 27, 2015 at 1:10 PM | Permalink

    More piling on: Those who say that “You can’t get blood from a stone” have obviously never read a paper by Michael Mann: such an enabled wonder-worker is he.

  46. David Brewer
    Posted Mar 27, 2015 at 7:46 PM | Permalink

    Briffa’s 2002 comment was prophetic. Mann’s methods always ignored mechanism. They produced estimates based on pure correlation, without any attempt to establish causation. That’s why he didn’t care whether his method turned sediment data upside down, whether there was another explanation for abnormal growth in some bristlecone pines, or even whether he mislocated records from Paris to Maine or from Spain to Tanzania. If a data series correlated with his target series in the reference period, and still correlated in the verification period, it was in.

    So Mann has always skipped the step of explaining WHY a particular data series should be seen as a proxy for temperature – what physical mechanism connected the proxy to the target variable. Omitting this step, he was indeed just as capable of regressing the data again(st) any other target variable.

    The explanation of Figure 3 of the RC post on this shows that Mann, as part of Rahmstorf’s team, and still neglecting mechanism, has now got to the stage of producing a proxy of a proxy: “Time series of the temperature difference between the subpolar North Atlantic and the entire northern hemisphere, which can be interpreted as an indicator of the strength of the Atlantic circulation.” His temperature difference has been constructed with proxies and he now uses the difference itself as a proxy for the Atlantic circulation.

    This double proxy then replaces observations: the RC post contains no data on the Atlantic circulation at all: even the “instrumental” portion of Figure 3 is only instrumental data on the temperature difference, not instrumental data on the circulation. Such drawing of conclusions about the trend in a target variable without considering any data on that variable is not science, but divination.

    • tktom
      Posted Mar 28, 2015 at 8:36 AM | Permalink

      A double proxy replacing observation…the ultimate delusion

  47. TimTheToolMan
    Posted Mar 28, 2015 at 12:24 AM | Permalink

    “The new article by Rahmstorf and Mann (see RC here) has been criticized at WUWT (here here) for making claims about Atlantic Ocean currents based on proxies, rather than measurements.”

    This reminds me of Allen and Sherwood’s “Warming maximum in the tropical upper troposphere deduced from thermal winds”

    And it typifies climate science’s ability to essentially ignore the importance of the massive assumptions they make about causality vs correlation. This particular example is worse than most with many, many levels of assumption.

  48. Ron Graf
    Posted Mar 28, 2015 at 9:22 AM | Permalink

    H. Thomas Rossby, a professor at the URI Graduate School of Oceanography: “The ADCP measures currents at very high accuracy, and so through the repeat measurements we take year after year, we have a very powerful tool by which to monitor the strength of the current,” said Rossby. “There are variations of the current over time that are natural — and yes, we need to understand these better — but we find absolutely no evidence that suggests that the Gulf Stream is slowing down.”

    Rahmstorf and Mann completely ignore Rossby’s work as if they were on another planet. Or did they? Perhaps they decided Rossby’s direct measurements were so contaminated by his political views as to disqualify his work from deserving mention.

    When it’s to the point that scientists are this untrusting of each other, and the system, it’s time for funding authorities to go out of their way to craft studies that have two or more teams with competing bias working on the same projects reporting results publicly and simultaneously to eliminate confounding bias. If findings cannot be trusted they’re worthless (and a wasted expensive).

    steve: this is a different issue than the proxy reconstructions. Mann says that he’s considering something a bit different than Rossby. Whether that is true or not doesn’t affect the foolishness of using contaminated Finnish sediments to estimate Atlantic ocean currents.

    • Ron Graf
      Posted Mar 28, 2015 at 1:27 PM | Permalink

      Steve, to clarify my point, I believe it’s appropriate to cite any recent studies, regardless of approach, that directly pertains to the question being analyzed.

      And, in illustration of my opinion on competitive collaboration protocol, my advice would have been to have double the budget of one or both approaches facilitating a second adversarial team or call the whole thing off. If research is not trustable by an adversarial expert it’s worth as much as an opened pack of gum on the sidewalk.

3 Trackbacks

  1. […] The enigmatic Steve McIntyre of the solid Climate Audit site calls the new paper by Rahmstorf and Mann making claims about Atlantic Ocean currents based on proxies, rather than measurements “much worse than we thought.” […]

  2. […] ad mannium Ja, vi har gjemt den saftigste kritikken (til nå) til slutten. På Climate Audit kan kritikken fra Steve McIntyre som avslørte Dr. Mann forrige gang han kom med søpleforskning, […]

  3. […] […]


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