“we could only do this back to about 1700″

Here is a longer excerpt from the July 19, 2000 Raymond Bradley Climategate email posted earlier today:

[……At this point Keith Alverson throws up his hands in despair at the ignorance of non-model amateurs…]

But there are real questions to be asked of the paleo reconstruction.

First, I should point out that we calibrated versus 1902-1980, then “verified” the approach using an independent data set for 1854-1901. The results were good, giving me confidence that if we had a comparable proxy data set for post-1980 (we don’t!) our proxy-based reconstruction would capture that period well. Unfortunately, the proxy network we used has not been updated, and furthermore there are many/some/ tree ring sites where there has been a “decoupling” between the long-term relationship between climate and tree growth, so that things fall apart in recent decades….this makes it very difficult to demonstrate what I just claimed. We can only call on evidence from many other proxies for “unprecedented” states in recent years (e.g. glaciers, isotopes in tropical ice etc..).

But there are (at least) two other problems — Keith Briffa points out that the very strong trend in the 20th century calibration period accounts for much of the success of our calibration and makes it unlikely that we would be able be able to reconstruct such an extraordinary period as the 1990s with much success (I may be mis-quoting him somewhat, but that is the general thrust of his criticism). Indeed, in the verification period, the biggest “miss” was an apparently very warm year in the late 19th century that we did not get right at all. This makes criticisms of the “antis” difficult to respond to (they have not yet risen to this level of sophistication, but they are “on the scent”).

Furthermore, it may be that Mann et al simply don’t have the long-term trend right, due to underestimation of low frequency info. in the (very few) proxies that we used. We tried to demonstrate that this was not a problem of the tree ring data we used by re-running the reconstruction with & without tree rings, and indeed the two efforts were very similar — but we could only do this back to about 1700.

Whether we have the 1000 year trend right is far less certain (& one reason why I hedge my bets on whether there were any periods in Medieval times that might have been “warm”, to the irritation of my co-authors!). So, possibly if you crank up the trend over 1000 years, you find that the envelope of uncertainty is comparable with at least some of the future scenarios, which of course begs the question as to what the likely forcing was 1000 years ago. (My money is firmly on an increase in solar irradiance, based on the 10-Be data..).

Another issue is whether we have estimated the totality of uncertainty in the long-term data set used — maybe the envelope is really much larger, due to inherent characteristics of the proxy data themselves….again this would cause the past and future envelopes to overlap.

In Ch 7 we will try to discuss some of these issues, in the limited space available. Perhaps the best thing at this stage is to simply point out the inherent uncertainties and point the way towards how these uncertainties can be reduced. Malcolm & I are working with Mike Mann to do just that.

In an earlier post, I criticized the repugnant attitude in which Bradley sneered at “antis” who had not yet reached the “level of sophistication” sufficient to disentangle adverse results that Bradley and coauthors had failed to report, but were “on the scent”.

In the present post, I wish to focus on a different point, the one referred to in the following paragraph:

Furthermore, it may be that Mann et al simply don’t have the long-term trend right, due to underestimation of low frequency info. in the (very few) proxies that we used. We tried to demonstrate that this was not a problem of the tree ring data we used by re-running the reconstruction with & without tree rings, and indeed the two efforts were very similar — but we could only do this back to about 1700. [my bold]

It seems certain to me that Bradley is here referring to the analysis in Mann et al 2000( Earth Interactions), which had an online version at NOAA here. The published version of this article states that it was “Received 11 May 1999; accepted 31 May 2000. (in final form 15 June 2000) ]”. Thus it was very recent (to say the least) at the time of Bradley’s July 10, 2000 email. It is my surmise (though this is just a surmise) that this article combined with the interactive web presentation was what Bradley was referring to in the closing paragraph of his July 20, 2000 email (though nothing turns here on the correctness of this surmise):

Perhaps the best thing at this stage is to simply point out the inherent uncertainties and point the way towards how these uncertainties can be reduced. Malcolm & I are working with Mike Mann to do just that.

MBH98 had stated that “the long-term trend in NH is relatively robust to the inclusion of dendroclimatic indicators in the network”. No supporting evidence is given for this statement in MBH98. The only support appears to come from the Mann et al 2000 article, which gives the following summary statement:

We have also verified that possible low-frequency bias due to non-climatic influences on dendroclimatic (tree-ring) indicators is not problematic in our temperature reconstructions.

Note that this statement is much broader and much more categorical than the one in Bradley’s email, where he admitted to insiders that their results not hold up for the pre-1700 networks.

This statement in Mann et al 2000 linked to a NOAA webpage http://www.ncdc.noaa.gov/paleo/ei/ei_nodendro.html, which has itself attracted considerable commentary over the past few years. It stated:

MBH98 argued, furthermore, that biases unique to a particular type of proxy indicator (e.g., tree-ring widths) are less problematic for “multiproxy”-based reconstructions that make use of the complementary information in a diverse proxy network. MBH98 found through statistical proxy network sensitivity estimates that skillful NH reconstructions were possible without using any dendroclimatic data, with results that were quite similar to those shown by MBH98 based on the full multiproxy network (with dendroclimatic indicators) if no dendroclimatic indicators were used at all. We show this below for annual-mean reconstructions of Northern Hemisphere mean temperatures.

[my bold]

They illustrated this “finding” with a graphic showing their AD1760 reconstruction. They continued with a similar statement as above, but this time include the qualification that the graphic only shows the similarity for “the period in question”.

Also shown is the reconstruction based ONLY on dendroclimatic indicators (ie, no coral, ice core, or historical or instrumental indicators). Again, the primary features of the reconstruction are very similar. Whether we use all data, exclude tree rings, or base a reconstruction only on tree rings, has no significant effect on the form of the reconstruction for the period in question.[my bold] This is most probably a result of the combination of our unique reconstruction strategy with the careful selection of the natural archives according to clear a priori criteria. Furthermore, we note that Jones et al. (1998), get similar results for the recent changes using an almost completely different tree-ring network based on wood density from high latitude trees. These comparisons show no evidence that the possible biases inherent to tree-ring (alone) based studies impair in any significant way the multiproxy-based temperature pattern reconstructions discussed here.

The above statements, both individually and collectively, give an entirely different impression to the reader than Bradley’s email to Oldfield.

The argument in http://www.ncdc.noaa.gov/paleo/ei/ei_nodendro.html has continue to be cited, most recently in Hughes’ evidence to the Muir Russell Committee in early 2010. Hughes stated that it was “it was possible to make this comparison only for the period AD 1750 to 1980″ – a point obviously contradicted by Bradley’s email noting (adverse) results for earlier networks:

We published a comparison of our results including and excluding tree rings in the online journal Earth Interactions in 2000 http://www.ncdc.noaa.gov/paleo/ei/ei_nodendro.html showing that the decadal course of reconstructed temperatures was largely insensitive to the inclusion or exclusion of tree-ring data, including after 1960. At that time (in 2000), it was possible to make this comparison only for the period AD 1750 to 1980 because many of the records we used ended by 1980, and because, although there were plenty of tree-ring records before 1750, that was not true of the non-tree-ring data at that time.

The webpage http://www.ncdc.noaa.gov/paleo/ei/ei_nodendro.html was cited in Mike Mann’s well-discussed Sep 22, 1999 email 136. 0938018124.txt, leading up to hide the decline (though no attention was paid to this point in my earlier discussions of IPCC and the Trick). This was the email in which Mann noted “everyone in the room at IPCC was in agreement that this [the Briffa reconstruction] was a problem and a potential distraction/detraction from the reasonably concensus viewpoint we’d like to show w/ the Jones et al and Mann et al series”, later adding that he didn’t want to give “fodder” to the skeptics.

Mann supported his email with a reference to the supposed nodendro argument as follows:

One other key result with respect to our own work is from a paper in the press in “Earth Interactions”. An unofficial version is available here: http://www.ngdc.noaa.gov/paleo/ei/ei_cover.html

The key point we emphasize in this paper is that the low-frequency variability in our hemispheric temperature reconstruction is basically the same if we don’t use any dendroclimatic indicators at all (though we certainly resolve less variance, can’t get a skillful reconstruction as far back, and there are notable discrepancies at the decadal and interannual timescales). A believe I need to add a sentence to the current discussion on this point, since there is an unsubstantiated knee-jerk belief that our low-frequency variability is suppressed by the use of tree ring data.

We have shown that this is not the case: (see here: http://www.ngdc.noaa.gov/paleo/ei/ei_datarev.html and specifically, the plot and discussion here: http://www.ngdc.noaa.gov/paleo/ei/ei_nodendro.html

Ironically, you’ll note that there is more low-frequency variability when the tree ring data *are* used, then when only other proxy and historical/instrumental data are used!

SO I think we’re in the position to say/resolve somewhat more than, frankly, than Keith does, about the temperature history of the past millennium.

Tim Lambert and others have attempted to argue that this is adequate disclosure. They point to the qualification in the commentary that the result applies only for the “period in question”, disregarding the failure of Bradley and others to report the opposite results in earlier periods. Due to the Climategate email, we now know that Bradley and coauthors were aware of the adverse results in earlier periods (notwithstanding Hughes’ evidence to the Muir Russell panel.) Once again, we see the differences between “full, true and plain disclosure” and Team practices. In a “full, true and plain disclosure” regime, Bradley and co-authors would be obliged to disclose the adverse results for the networks prior to AD1700.


42 Comments

  1. Keith Grubb
    Posted Feb 21, 2011 at 3:35 PM | Permalink

    OK, my first post got snipped. Let me try the opposite direction. A true crisis sometimes requires honesty. The somewhat honest people from Muir-Russell, and Penn State, did a thorough investigation and found no wrong doing. Sometimes, when you’re “reviewer A” it requires you to be honest.

    • James Evans
      Posted Feb 22, 2011 at 1:32 PM | Permalink

      I’m assuming that you forgot to put “/sarc”.

    • JD Ohio
      Posted Feb 23, 2011 at 6:44 PM | Permalink

      Simply ridiculous. Phil Jones was never even asked whether he did in fact delete emails. The CRU lie [or deletion of data] that occurred in conjunction with the request of Warwick Hughes and Pielke jr. was not vetted. The so-called investigations arising out of Climategate were really whitewashes that were the equivalent of the police going to an accused murderer’s mother and asking her whether her son had killed someone.

      JD

  2. Daniel
    Posted Feb 21, 2011 at 3:48 PM | Permalink

    Steve,

    One more crual story about long term dendrochronlogy / multi proxy based reconstructions.

    Well apart from illustrating shortfalls in openess and transparency & personal conduct from individuals, this only adds to the reasons why most recent reports from scientific societies on climate change (Royal Society, French Academy of Sciences…) no longer take into account arguments from long term climate reconstructions. Given how keen these societies remain to justify and support the climate mitigation policies, this speaks volume about today’s weak status of this scientific (??) disciplin !

  3. Posted Feb 21, 2011 at 3:53 PM | Permalink

    “Furthermore, it may be that Mann et al simply don’t have the long-term trend right, due to underestimation of low frequency info.”

    The low frequency reconstructions calibrated to temperature were much too inconvenient when proving a preconceived notion.

  4. Craig Loehle
    Posted Feb 21, 2011 at 4:28 PM | Permalink

    As a reminder of why the reconstructions deteriorate for older periods when tree rings are included:
    Loehle, C. 2009. A Mathematical Analysis of the Divergence Problem in Dendroclimatology. Climatic Change 94:233-245
    available at:

    http://www.ncasi.org//Publications/Detail.aspx?id=3273

    • Yancey Ward
      Posted Feb 21, 2011 at 5:19 PM | Permalink

      Seems to me it is even worse than that- if you see a divergence now, how can you have any confidence at all that it is one that is unique?

    • Duster
      Posted Feb 22, 2011 at 9:11 PM | Permalink

      I get a “catastrophic error” report for the link at the moment.

  5. Posted Feb 21, 2011 at 5:41 PM | Permalink

    Clarification request: I see from the above excerpts that they couldn’t do the comparison back before 1700 because there weren’t enough non-dendro series to create a non-dendro-only reconstruction, but what are the “adverse results”?

    Steve- the excerpt does not specifically say that “there weren’t enough non-dendro series to create a nondendro reconstruction.” My interpretation was that they had done the nodendro reconstruction but didn’t get the result that they were looking for.

    The vast majority of MBH proxies are dendro. Most of the AD1700 non-dendro proxies are ice cores and are available earlier. I don’t understand why they would be able to do a recon using AD1700 nodendro proxies, but would not be able to do something for AD1400 nodendro proxies.

    The actual webpage only shows the AD1760 network. I just noticed something interesting about this particular nodendro network – it includes 6 long instrumental records as “proxies”.

    It doesn’t seem to me like a very remarkable achievement to reconstruct instrumental temperature if you use temperature records as “proxies”. Nor does it seem to me that Mann, Bradley and associates should extrapolate from their apparent ability to reconstruct NH temperature from the AD1760 proxy network (long instrumental series included) to networks without instrumental series.

    I hadn’t noticed this particular aspect to their claim before.

    Once the long instrumental series are removed from the network, I suppose that they could argue that there weren’t enough non-dendro series to do the reconstruction. But I wonder whether they can even make this claim for the AD1760 network without the instrumental series inappropriately included as “proxies”. An interesting dig-here.

    • Geoff Sherrington
      Posted Feb 22, 2011 at 5:21 AM | Permalink

      Part of the answer might be within email 965416206.txt on 4 Aug 2000, from Keith Briffa to Fortunat Joos, soon after the discussion that Steve has quoted above. Here is a part

      The Etheridge ice core data of CO2 indicate that CO2 was below average
      in the 17th and 18th centuries by a few ppm. Very few (1-2 points) of
      ice core C13 data (Francey tellus, 99) suggest that this drawdown was
      caused by additional terrestrial carbon storage (Joos et al, GRL, 99;
      Trudinger, Tellus, 99). We try to investigate this suggestion using the
      Lund-Potsdam-Jena dynamical global vegetation model (LPJ-DGVM).
      A diploma student of mine, Philippe Bruegger, has used the Mann et al
      annual mean temperature patterns (2 EOFs only) in combination with the
      Etheridge CO2 record to drive the LPJ model. Instead of absorbing
      carbon, the model is releasing carbon due to a reduced CO2 fertilization
      effect in the model that outweights any climatic effects. Thus, the
      model results is clearly not compatible with the ice core results.
      Obviously, the study is hampered by the limitation of the climate
      reconstruction (as well as by the few C13 ice core data). Instead of
      changes in monthly values of Temp and precip (and cloud cover) changes
      in ANNUAL mean temperature were used to force LPJ.
      …………………….

      Do these sound like “adverse results”?

  6. Posted Feb 21, 2011 at 6:54 PM | Permalink

    If they referenced Mann 09, then they knew about his SI:

    “…In addition to the tests described by ref. S1 which removed alternatively (a) all tree-ring data or (b) 7 additional long-term proxy records associated with greater uncertainties or potential documented biases (showing the temperature reconstruction was robust to removal of either of these datasets), we here removed both data sets simultaneously from the predictor network (Fig. S8). This additional test reveals that with the resulting extremely sparse proxy network in earlier centuries, a skillful reconstruction is no longer possible prior to AD 1500. Nonetheless, even in this case, the resulting (unskillful) early reconstruction remains almost entirely within the estimated error bounds of the original reconstruction…”

    So the Author himself chopped out the base of his earlier study in MBH98 – “…a skillful reconstruction is no longer possible prior to AD 1500…”

    This subject was also broached in this post:

    http://climateaudit.org/2010/08/01/the-no-dendro-illusion/

  7. Posted Feb 21, 2011 at 7:49 PM | Permalink

    Speaking of not disclosing “adverse results”, folks might like to look at my post that McIntyre misrepresents as attempting “to argue that this is adequate disclosure”.

    Steve-
    Lambert is objecting to the precision of my language not in a CA blog post, but in a comment #348 in a comment thread at Keith Kloor’s, in which I stated:

    To be clear the “22 series” include two PC1s, which are calculated from larger networks. Mann’s idiosyncratic PC methodology effectively “threw out” all the NOAMER dendro data in this step except the bristlecones.

    Mann obviously objected at the time (and subsequently) to reconstructions without bristlecones, with the objections couched in language of retained principal components – that sort of thing. But the issue was the weight applied to bristlecones.

    The non-Stickness of Mann-style reconstructions without bristlecones+Gaspe or with reduced bristlecone+Gaspe weight – a point conceded by Wahl and Ammann – was inconsistent with MBH98 claims that their results were “robust” to the prsence/absence of dendroclimatic indicators. MBH98 stated that “the long-term trend in NH is relatively robust to the inclusion of dendroclimatic indicators in the network”, apoint made even more forcefully in a note to Mann et al 2000, which stated:”Whether we use all data, exclude tree rings, or base a reconstruction only on tree rings, has no significant effect on the form of the reconstruction for the period in question.

    The points in my comment are correct. MBH clearly attempted to give the impression that their reconstruction was robust to the presence/absence of dendro indicators without limiting their claim to the AD1760 network, as shown in the review in the head blog post here. Robustness restricted to the AD1760 network was of no interest to anyone. As I say in the head post, Bradley and his coauthors should have clearly disclosed that their claim of “robustness” did no hold up for pre-1700 networks.

    It is amazing that Lambert chooses to parse not even blog posts, but theaded blog comments, but is unoffended by the lack of disclosure by Bradley and Mann in “the peer reviewed literature”.

    I previously commented to Lambert on the same point in 2006 here:

    Mann said:

    “the long-term trend in NH is relatively robust to the inclusion of dendroclimatic indicators in the network”

    A foritiori, it is relatively robust to the inclusion of bristlecones. It isn’t and Mann knew it.

    Mann said:

    We have also verified that possible low-frequency bias due to non-climatic influences on dendroclimatic (tree-ring) indicators is not problematic in our temperature reconstructions.

    That’s false. He tested removing bristlecones from the network and got the opposite result.

    Mann said:

    MBH98 found through statistical proxy network sensitivity estimates that skillful NH reconstructions were possible without using any dendroclimatic data, with results that were quite similar to those shown by MBH98 based on the full multiproxy network (with dendroclimatic indicators) if no dendroclimatic indicators were used at all.

    That’s false. The results without bristlecones are not “quite similar”. They’re very different.

    He says:

    Whether we use all data, exclude tree rings, or base a reconstruction only on tree rings, has no significant effect on the form of the reconstruction for the period in question.

    This is a promoter’s trick. Your only excuse is that Mann didn’t lie here about the 1760 period. But he knew that this was false for the earlier periods. In a prospectus, that would be against securities laws. The other false statements would be violations of securities laws in a prospectus. So would the withholding of the adverse verification results.

    You are defending what would be violations of securities laws in a prospectus. You are pathetic.

    • Posted Feb 21, 2011 at 8:02 PM | Permalink

      Is anyone trying to re-structure the world based on Steve’s blog posts?

      • kim
        Posted Feb 22, 2011 at 8:02 AM | Permalink

        Argument structure
        Leads the pack’s correct pursuit.
        Legal beagles bay.
        ============

    • DEEBEE
      Posted Feb 22, 2011 at 5:55 AM | Permalink

      Darn Steve, when will you start acting your age and become forgetful, so that Lambert has a chance.

    • S Geiger
      Posted Feb 22, 2011 at 8:20 AM | Permalink

      Well thought out, measured response to Mr. Lambert. That’s why CA maintains the highest degree of credibility. Thanks.

    • Posted Feb 22, 2011 at 9:44 AM | Permalink

      McIntyre claims:

      MBH clearly attempted to give the impression that their reconstruction was robust to the presence/absence of dendro indicators without limiting their claim to the AD1760 network

      Their actual words:

      Note that the NH reconstruction based on the sparse “non-dendro” multiproxy network (19 non-dendro indicators available back to 1760) is remarkably similar to that based on the full (more than 100 indicators) multiproxy network of MBH98.

      Who should you beleive McIntyre, or your lying eyes?

      What’s amusing, is that the faithful have already chimed in — they’ll believe McIntyre, no matter what the actual words say.

      • Posted Feb 22, 2011 at 10:33 AM | Permalink

        Here is what MBH98 (p. 783) says:

        ..the long-term trend in NH is relatively robust to the inclusion of dendroclimatic indicators in the network, suggesting that potential tree growth trend biases are not influential in the multiproxy climate reconstructions.

        and in Mann et al 2000:

        We have also verified that possible low-frequency bias due to non-climatic influences on dendroclimatic (tree-ring) indicators is not problematic in our temperature reconstructions…Whether we use all data, exclude tree rings, or base a reconstruction only on tree rings, has no significant effect on the form of the reconstruction for the period in question…These comparisons show no evidence that the possible biases inherent to tree-ring (alone) based studies impair in any significant way the multiproxy-based temperature pattern reconstructions discussed here.

        No mention of limiting to 1760 anywhere.

        • Posted Feb 22, 2011 at 6:54 PM | Permalink

          John Andrews does exactly the same quote mine as McIntyre. There is not mention of limiting it to 1760 in his quote because he deliberately removed it from his quote. The paragraph he quotes from begins like this:

          Note that the NH reconstruction based on the sparse “non-dendro” multiproxy network (19 non-dendro indicators available back to 1760) is remarkably similar to that based on the full (more than 100 indicators) multiproxy network of MBH98.

          Anyone can use their own eyes to see that there are limiting it to going back to 1760. The McIntyre faithful seem to suffer from a special form of blindness that prevents them from seeing the mention of 1760 in that paragraph.

        • Mark T
          Posted Feb 22, 2011 at 10:01 PM | Permalink

          Still sticking to your hobby-horse, not surprisingly.

          You can’t win on the technical points so you shoot for semantics (not that you can win there, either.)

          You’re pathetic.

          Mark

        • MrPete
          Posted Feb 22, 2011 at 10:55 PM | Permalink

          Re: Tim Lambert (Feb 22 18:54),
          Tim, you have quote-mined yourself. Or maybe you didn’t bother to click on the links referred to by the sentence you quoted? Here is the FULL context of that quote (bottom of page):

          Full Multiproxy Network Data
          No Tree Ring Data
          Tree Ring Only Data

          NH temperature reconstructions based on all records, and on subsets excluding or comprising exclusively of, tree-ring data.

          Note that the NH reconstruction based on the sparse “non-dendro” multiproxy network (19 non-dendro indicators available back to 1760) is remarkably similar to that based on the full (more than 100 indicators) multiproxy network of MBH98. Because the sampling of the “no-dendro” dataset is much sparser, we expect that it will be more influenced by regional variations, and less representative of the true NH mean temperature.

          Now, let’s test your claim that “Anyone can use their own eyes to see that they are limiting it to going back to 1760.”
          Clearly the text says the “non-dendro” multiproxy network only goes back to 1760. Click the (second) link right there and… voila, it is true: they only provide data back to 1760.

          Is it clear that the reconstruction “based on the full multiproxy network” is likewise limited? Click on the first link. Hmmm… sure appears to go back to 1400 to me.

          Even more telling: we know their dendro data went back earlier than 1760: it was part of their selection criteria (further up the page). And we know they had non-dendro (ice etc) data going back earlier than 1760.

          So… why limit the graph to this period?…
          * Why include physical temperature records in the non-dendro “proxy” data, as SM has noted?
          * Why use this limit when we know they had data for earlier periods? And,
          * Why is there no mention of the proxy failure in earlier periods?

          Now that I’ve read through it, I too am curious. Sure looks like a cherry-picked “good” result.

      • Ryan O
        Posted Feb 22, 2011 at 10:42 AM | Permalink

        Tim,

        You miss the larger point, which Steve did communicate accurately. In Mann et al. 2000, the AD 1760 test was used to dismiss the claims of LF bias in the reconstruction despite the fact that pre-1760 non-dendro reconstructions did not show skill and the post-1760 network included actual instrumental temperatures (whereas the AD 1400 and AD 1000 non-dendro networks do not).

        Owing to the decreased number of spatial degrees of freedom in the earliest reconstructions (associated with significantly decreased calibrated variance before e.g. 1730 for annual-mean and cold-season, and about 1750 for warm-season pattern reconstructions) regional inferences are most meaningful in the mid 18th century and later, while the largest-scale averages are useful further back in time. For example, the NH annual mean temperature series appears to exhibit skill back to at least AD 1400 (and has now been extended back to AD 1000 by Mann et al (1999), albeit with expanded uncertainty estimates). We have also verified that possible low-frequency bias due to non-climatic influences on dendroclimatic (tree-ring) indicators is not problematic in our temperature reconstructions {my bold}.

        This then goes to the page where they note that the test was performed only back to 1760, which makes no statement on the AD 1000 or AD 1400 reconstructions. Yet they still go on to conclude:

        These comparisons show no evidence that the possible biases inherent to tree-ring (alone) based studies impair in any significant way the multiproxy-based temperature pattern reconstructions discussed here {my bold}.

        The “reconstructions discussed here” include the AD 1000 and AD 1400 reconstructions which do not utilize the same predictors as the AD 1760 network. Notably missing are the instrumental temperatures in the AD 1000 and AD 1400 networks. The test they perform is valid only for the AD 1760 network – not the earlier non-dendro networks – yet they are clearly using the test to conclude that the earlier dendro networks show no significant LF bias.

      • Dave
        Posted Feb 22, 2011 at 12:39 PM | Permalink

        Tim, can you just state clearly whether or not you believe there is evidence of less-than-optimal behaviour (at the very least) shown in these emails?

      • Mark T
        Posted Feb 22, 2011 at 4:24 PM | Permalink

        Based on John A’s post (as well as what I already know about the subject) I’m gonna have to lean towards my lyin eyes on this one. You’re the only liar here, Tim.

        Mark

        • Dave Andrews
          Posted Feb 22, 2011 at 5:02 PM | Permalink

          Ever noticed Lambert NEVER discusses the science in any real depth on his blog.He always references other sources with minimal comment. A bit like ‘reverse trolling’ if you ask me.

        • Mark T
          Posted Feb 22, 2011 at 5:30 PM | Permalink

          Of course. I’ve been following since CA’s inception. Tim doesn’t have the requisite knowledge to debate the meat, so he chases after the chaffe hoping to get a hit. It must be awfully annoying knowing that the ONLY people that agree with the math used by The Team are members themselves…

          Mark

        • Posted Feb 22, 2011 at 5:56 PM | Permalink

          The position is always staked out beforehand.

      • Luis Dias
        Posted Feb 22, 2011 at 6:00 PM | Permalink

        Really, get over it, Tim. You’re not getting any points here by trolling this blog. Go back to your fanbase and have a party with them, and leave the serious stuff to grown ups, mkay?

    • Geoff Sherrington
      Posted Feb 22, 2011 at 6:55 PM | Permalink

      Part of email from Ray Bradley (co-author of Hockeystick concepts) to Frank Oldfield 10 July 2000 under the header “the ghost of futures past”. 1104893567.txt

      The biggest problem with what appears here is in the handling of the greater
      variability found in some reconstructions, and the whole discussion of the ‘hockey stick’.
      The tone is defensive, and worse, it both minimizes and avoids the problems. We should clearly say (e.g., page 12 middle paragraph) that there are substantial uncertainties that remain concerning the degree of variability – warming prior to 12K BP, and cooling during the LIA, due primarily to the use of paleo-indicators of uncertain applicability, and the lack of global (especially tropical) data. Attempting to avoid such statements will just cause more problems.
      In addition, some of the comments are probably wrong – the warm-season bias (p.12) should if anything produce less variability, since warm seasons (at least in GCMs) feature smaller climate changes than cold seasons. The discussion of uncertainties in tree ring reconstructions should be direct, not referred to other references – it’s important for this document. How the long-term growth is factored in/out should be mentioned as a prime problem. ”

      Tim Lambert, why do criticise Steve McIntyre for suggesting a course of disclosure that had already been discussed by its designers who, by choice, converted a clear admission of uncertainties in tree ring reconstructions to an obscured generality?

    • SamG
      Posted Feb 23, 2011 at 6:04 AM | Permalink

      Apologies from Australia for Lambert….and The ABC

      http://www.theaustralian.com.au/national-affairs/bias-at-the-netional-broadcaster-is-as-easy-as-abc/story-fn59niix-1226009060141

  8. Posted Feb 21, 2011 at 8:00 PM | Permalink

    I believe this is related, and I’ve pointed it out before, and Steve has expressed an interest but I don’t think he’s posted on this one. Seems apropos here since we’re talking about uncertainty, Bradley, and “full, true and plain disclosure”.

    This is CRU email 1062592331.txt, dated 3 Sep, 2003, from Ed Cook to Keith Briffa. Ed is discussing some things he’s presented recently, and has a couple disparaging comments about Bradley. Then he proposes a new project entitled “Northern Hemisphere Temperatures Over The Past Millennium: Where Are The Greatest Uncertainties?” He then lists several bullet points outlining what the paper would cover.

    The money quote, down near the bottom, is this one (two F-bombs have been sanitized for your protection):

    Without trying to prejudice this work, but also because of what I almost think I know to be the case, the results of this study will show that we can probably say a fair bit about <100 year extra-tropical NH temperature variability (at least as far as we
    believe the proxy estimates), but honestly know f***-all about what the >100 year variability was like with any certainty (i.e. we now with certainty that we know f***-all).

    So it seems even 1700 is a very liberal estimate.

  9. LarryT
    Posted Feb 22, 2011 at 5:08 AM | Permalink

    I thought that the Mannian reconstrutions were not dependent on use of “real” data and produce same results no mather what input was used.

  10. Posted Feb 22, 2011 at 7:02 AM | Permalink

    What is the “Ch 7″ referred to in this email?
    It can’t be IPCC TAR Ch 7 – is it a typo for IPCC TAR Ch 2?
    Or is it some other book?

  11. Craig Loehle
    Posted Feb 22, 2011 at 9:37 AM | Permalink

    It is interesting to note that in speeches persuant to introducing amendments to the House budget to defund IPCC (and other things), climategate was mentioned, as was Hide the Decline, and the mentions I saw seemed correct. Kudos. I’m sure you have a big check somewhere from an oil company (not)!

  12. Posted Feb 22, 2011 at 10:08 AM | Permalink

    When I look back into the archives, there is a discussion on the exact same topic in March 2005: http://climateaudit.org/2005/03/24/bristlecone-pines-again/ with the exact same argument in the comments about whether non-dendro to 1760 is “remarkably similar” or not.

    Is it Groundhog Day?

  13. Kenneth Fritsch
    Posted Feb 22, 2011 at 10:39 AM | Permalink

    “Note that the NH reconstruction based on the sparse “non-dendro” multiproxy network (19 non-dendro indicators available back to 1760) is remarkably similar to that based on the full (more than 100 indicators) multiproxy network of MBH98.”

    Lambert, how in the heck does that statement counter what SteveM said? It would take a “faithful” view to think that that single statement is all that was said about the non-dendro reconstruction beyond 1760.

    The point is, of course, that the non-dendro reconstruction cannot be used to validate the dendro reconstruction back in time and this result came about from some backfilling after the fact.

  14. Frank
    Posted Feb 22, 2011 at 12:03 PM | Permalink

    Bradley wrote: “Indeed, in the verification period, the biggest “miss” was an apparently very warm year in the late 19th century that we did not get right at all.” Has anyone determined in what year the biggest miss occurred and how big the miss was? Is it possible that a few of the warmest years in the validation are big misses, suggesting that the methodology is only valid up to a certain temperature and not above?

  15. RoyFOMR
    Posted Feb 22, 2011 at 7:14 PM | Permalink

    More Greyhound than Bloodhound is Steve. His relentless logic and unforgiving recall just keeps grinding his opponent’s defences into fine powder and then to dust.
    Maybe not the legendary “Mick the Miller” but certainly “Mac the Miller”!

  16. Geoff Sherrington
    Posted Feb 23, 2011 at 1:17 AM | Permalink

    As a chemist, I read blogs from other chemists here like Pat Frank and DeWitt Payne. Chemists who have toiled at the lab bench have often met the concepts of parts per million and parts per billion. They will have learned how difficult it is to measure accurately at these levels, because there is so much potential interference in greater abundance in the surroundings. Those who use stability diagrams for equilibrium reactions – like the interactions in the oceans between pH, carbonate, bicarbonate, calcium and magesium and others – know that a small error in estimation of a key coefficient can make for large errors of understanding.

    Although I cannot know this, I suspect that many chemists first learning of the GHG theory of global warming started from a base of scepticism, from the knowledge that very small concentrations need extraordinary care and interpretation.

    I’m sorry, but I have not risen far above that base, despite thousands of pages of reading and study.

    That is my concern, rather more than the conduct of people who call themselves climate scientists. They might deal with climate, but the standard of the science if often poor. (Oh dear, I just corrected a bad typo, “slimate scientists”.)

  17. Venter
    Posted Feb 23, 2011 at 7:56 AM | Permalink

    Geoff,

    I’m a chemist myself and understand exactly what you mean. After over 27 years in this discipline starting with RND and QC, even with advances in instrumentation, I’m fully aware about how much are the difficulties involved in measuring low concentrations like ppm and ppb and measuring nanogram levels. And I’ aware of error margins and sensitivities and the need for absolutely ruthless data and method validations and controls.

    So when you see these so called ” scientists ” with their sloppy data, lousy methods, non-existent data archiving, blatant data manipulations, lousy maths and lousy statistics proclaim accuracies to the order of 3 decimal points, I feel like throwing a boulder at the whole lot of charlatans.

  18. Posted Feb 23, 2011 at 1:55 PM | Permalink

    Any thoughts on Judith Curry’s latest post…

    http://judithcurry.com/2011/02/22/hiding-the-decline/#comment-46633

    Over 800 comments in less than a day. Gavin appears a bit cross as well.

    The gloves appear to be completely off with respect to ‘Hide the Decline’ folliwng Professor Beddington’s thoughts on psudo-science recently.

    Judith Curry:

    “However, two things this week have changed my mind, and I have decided to take on one aspect of this issue: the infamous “hide the decline.”

    The first thing that contributed to my mind change was this post at Bishop Hill entitled “Will Sir John condemn hide the decline?”, related to Sir John Beddington’s statement: It is time the scientific community became proactive in challenging misuse of scientific evidence.”

    AND:

    “McIntyre’s analysis is sufficiently well documented that it is difficult to imagine that his analysis is incorrect in any significant way. If his analysis is incorrect, it should be refuted. I would like to know what the heck Mann, Briffa, Jones et al. were thinking when they did this and why they did this, and how they can defend this, although the emails provide pretty strong clues. Does the IPCC regard this as acceptable? I sure don’t.

    Can anyone defend “hide the decline”? I would much prefer to be wrong in my interpretation, but I fear that I am not.”

    • suyts
      Posted Feb 23, 2011 at 5:12 PM | Permalink

      I don’t think she was prepared for the vitriol she unleashed. Although, reading her posting, it seemed like she was calling them out. I like the subject of tree rings, because they’re fun to make fun of. I also find it interesting I was the only one to mention McShane and Wyner on that thread. That should be all that is necessary for most of that conversation. McShane & Wyner and some God given common sense would tell us that there’s absolutely no way someone can discern a decadal temp out of tree rings to a 10th of a degree accuracy.

3 Trackbacks

  1. By Climate Bloodhounds | Watts Up With That? on Feb 22, 2011 at 10:47 AM

    […] Bradley has doubts,  as Steve points out in a second post, here’s more from the same Climategate email by Bradley: Furthermore, it may be that Mann et […]

  2. By Top Posts — WordPress.com on Feb 22, 2011 at 7:15 PM

    […] “we could only do this back to about 1700″ Here is a longer excerpt from the July 19, 2000 Raymond Bradley Climategate email posted earlier today: […]

  3. […] Source: http://climateaudit.org/2011/02/21/we-could-only-do-this-back-to-about-1700/ […]

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