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An Open Invitation For Jan Perlwitz

January 19, 2013

By Paul Homewood


In my guest post at WUWT, GISS – Cooling The Past – Warming The Present, which Anthony ran on Friday, Jan Perlwitz left the following comment:-

Once more, Mr. Watts posts an article on his blog, which insinuates that GISS scientists committed fraud, i.e., they are being accused of doing not scientifically legitimate manipulations of the data for the purpose to deceive, by making the anthropogenic influence on climate larger than it was. The “skeptic” crowd in the forum understands the cue and transforms the insinuation into open accusation.

I should explain that Jan is an Associate Research Scientist, who works with GISS, although, as I understand, he is actually employed by Columbia University.


In reply, I left the following comment:-

Jan P Perlwitz,

Perhaps then you can explain why such big adjustments have been made to Icelandic data?

In October, I asked NOAA to provide the calculations GHCN had made for one station in Iceland for homogenisation. Bryant Korzeniewski at NOAA told me this would not be a problem. Yet 3 months later, I still have no reply, despite chasing several times.

I realise you work for GISS, but I am sure in the interests of transparency, you could use your influence at NOAA to expedite this.

But it gets worse! On top of GHCN adjustments, GISS have substantially INCREASED the warming trend at Reykjavik for UHI, instead of REDUCING it. The Iceland Met confirm there have been no station changes etc that would justify this. But when I challenged Reto Ruedy, he was unable to explain it either.

Then you wonder why we don’t trust your data!

So far I have had no reply from Jan, and, to be fair, I was not expecting one as I would not have expected him to return to the site after his initial comment.


So I am now extending this opportunity to Jan to address these two specific questions, in the hope that he can restore some of the trust and confidence in GISS/NOAA, that many of us feel is sadly lacking.

In anticipation, thank you Jan.



It is evident from his comment, that Jan fails to appreciate that one of the reasons for the distrust, is that GISS are not open about these changes that they make. If they can justify them, they should publish them openly and transparently, and also keep the original data fully archived. It should not be up to independent bloggers to have to ferret all this out.

  1. Andy DC permalink
    January 19, 2013 7:16 pm

    Yes, unless someone can explain why there is such an outrageous bias toward cooling the past and warming the present, there is an obvious appearance of blatant fraud. Increasing population and development around airport weather stations would lead one to believe that if anything, the “adjustments” should be just the opposite.

    When a multibillion dollar agenda is at stake, if it walks like a duck and quacks like a duck, it is a duck (fraud) until otherwise proven! Saying that “we are above reproach” and not proving it does not cut it.

  2. mitigatedsceptic permalink
    January 19, 2013 8:11 pm

    I don’t think that those who work in the climatology field fully understand that there are battalions of anti-science people just waiting to jump to arms at the slightest sign of any scientific project being unreliable. Although we all know that science is not a single discipline and that different conventions of ‘truth-proof’ prevail in different branches of science, people anxious to promote their own world-view are all too ready to pounce.
    So not only is it vital that the AGW be clarified because of its devastating economic effects, the reputation of ALL the empirical science is at stake.
    There is nothing wrong with changing one’s mind, but changing data without explanation is in a different league altogether.
    Where are the referees? Do they tolerate changing published data without submitting the proposed changes to adjudication?
    In the business world, attention is directed to the malefactor, but rarely to the auditor who was supposed to have validate the data. Is science succumbing to the same blight?

  3. January 20, 2013 1:05 am

    Reblogged this on Climate Ponderings.

  4. Billy Liar permalink
    January 20, 2013 8:05 pm

    Calling Jan Perlwitz … … (sound of crickets).

  5. Rosco permalink
    January 21, 2013 11:09 pm

    In Australia one of our climate experts from the BOM – I missed the name is the snippet of the radio broadcast I heard – admitted the Australian BOM were actively involved in tampering with past temperature results.

    The reasoning he gave is that many records from the past were measurements made in direct sun and at inappropriate heights above ground level.

    Of course the modern UHI effect of asphalt and Jet engine exhausts at major airports is perfectly acceptable practice !

    How they know which measurements require adjusting not having any direct evidence to substantiate this is a relevant question.

    Perhaps they simply pick the hottest and say – that one is obviously wrong – it exceeds the records for the hottest decade – the naughties till now !

  6. February 6, 2013 9:29 pm

    Paul Homewood,

    I want to say following in reply to your posting, in which you gave me the honor to make my name part of the title.

    1. Different to your assertion, I have been at the mentioned website and submitted comments, which partly appeared, whereas others were censored away, also after my comment to your posting there. I just have not bothered to reply in the specific thread anymore. Mr. Watts or his moderators censor quite a number of my comments submitted at his site. Apparently, he does not appreciate to be contradicted too much, particularly by people who actually work in the field. He seems to like all the clapping better he gets from his devote followers in the comment section.

    2. I do not see that your reply to my comment really warranted another reply by me. I had written more than you quoted above, although one can see that when one goes through the link to my full comment at Mr. Watts’s blog. You didn’t bother to reply to what I actually wrote. Instead you just added some more assertions regarding one specific station. And then you are requesting some action from my side, just because you make some assertions? I do not feel like your errand boy.

    3. The methodology and the scientific explanation for the adjustments to data made for the surface temperature analysis has been published in the peer reviewed literature by the scientists who do the analysis. The computer programs they use at GISS for the analysis are public and can be downloaded from the GISS website. Thus, if one wanted one could track down for every single station where the adjustments happen in the code, after the input data go in. Therefore, I do not see where your assertion those adjustments were not public or transparent is coming from.

    4. If you believe the surface temperature analysis at GISS was not properly done by the scientists, the adjustments that were part of the analysis, were not scientifically valid and that invalid adjustments distorted the results from the analysis statistically significantly compared to an allegedly correct analysis, or even the whole global warming seen in the results from the surface temperature analysis was just made up using false adjustments, then the proper way would be to provide the scientific evidence to refute the GISS analysis. Scientific evidence is provided by doing your own statistical analysis using correct methodology, demonstrating the errors in the criticized analysis and showing where the scientific reasoning for the adjustments goes wrong in the published papers, and by publishing the results of your own analysis in a peer reviewed journal of the field. Not by assertion in opinion blogs.

    5. You can claim your distrust in what some scientists are doing all you want. Everyone is allowed to have an opinion. You are definitely within your rights with this. Trust is just not a parameter for the validity of scientific arguments and results.

    • February 6, 2013 11:17 pm

      Thank you , Jan. As I said, I can fully understand why you would not have responded to my original comment.

      Nevertheless you fail to answer either of my questions. It really is not up to me to prove anybody wrong, it is up to the people who make the adjustments to justify them.

      If I ask a question, and an answer, that is apparently so easy, is promised but then not given, I am entitled to ask why.

      So, I repeat:-

      Why were the GHCN adjustments made in Stykkisholmur, and why did the GISS UHI adjustments increase the warming trend at Reykjavik?

      It should really be easy to answer these two questions, according to what you say.

      PS Perhaps you could also explain why GISS global temperature measurements are revised retrospectively, without proper archiving or explanation, and why it is up to independent bloggers such as me to bring them to people’s attention?

      In the interests of transparency, all these questions deserve answers.

      • February 7, 2013 12:26 am

        Paul, you wrote:

        Nevertheless you fail to answer either of my questions

        Yes, and I am going to continue to fail because there is no reasonable explanation from you why you think that it would be my place or job to answer your questions. As far as I see it, your questions are based on mere assertions, anyway.

        It really is not up to me to prove anybody wrong, it is up to the people who make the adjustments to justify them.

        They have published their methodology, i.e., they have given the scientifically relevant explanations. If you have peer reviewed scientific methodology and results of an analysis applying this methodology, it is up to you to refute it. If you don’t agree with what is done.

        If I ask a question, and an answer, that is apparently so easy, is promised but then not given, I am entitled to ask why.

        Excuse me? What are you talking about? I haven’t promised you anything. Now you are making things up.

        PS Perhaps you could also explain why GISS global temperature measurements are revised retrospectively, without proper archiving or explanation, and why it is up to independent bloggers such as me to bring them to people’s attention?

        Loaded question, which states presumptions, which are falsehoods.

        The scientific explanations for the applied methodology can be found in the papers of the scientists who do the analysis. The most recent one is this one:

        The explanations for technical changes (e.g., changes from changes in the input data, bug fixes) are all given here:

        Besides, there are no “GISS global temperature measurements”. GISS does not do temperature measurements.

      • February 7, 2013 10:57 am

        If I ask a question, and an answer, that is apparently so easy, is promised but then not given, I am entitled to ask why.

        I have asked this question, as I explained, of GHCN. I have simply asked you to see if you can help me get an answer from them, so please don’t accuse me of saying things I have not done. So I repeat my request. Any help would be gratefully received. Whether you think my questions are based on mere assertions or not has no relevance at all.
        I am sure you will agree that this lack of response from a publically funded organisation is neither professional nor acceptable.

        We are however getting away from the original post on the changes to the temperature record, that you originally commented on.

        You have not queried any of my numbers, so I assume you accept that my analysis was correct.

        I happen to think that people are entitled to know about such changes. Do you?

  7. Andy DC permalink
    February 7, 2013 2:10 am


    Somehow, somewhere someplace there is justification for what appears to be blatant fruad. Instead of being your errand boy and giving you a simple explanation, I expect you to spend a couple thousand hours on a wild goose chase, trying to find an explanation for our 99.9% warm biased adjustments that does not exist. But nevertheless we are above reproach and you should blindly go along with whatever we determine. That is what the scientific method is all about.

  8. July 18, 2013 11:06 pm

    The GISS was subject to Bureaucratic Capture long ago. Its prolonged subjugation has rendered it not only unfit for purpose, but malign. Defunding and dissolution are the institutional remedies. The individual ones must be judicial.

    • July 18, 2013 11:27 pm

      You are dreaming of a witch hunt and prosecuting scientists soley based on denunciation and smear, aren’t you. What about if the likes of you were in power.

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