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How GHCN Keep Rewriting Reykjavik History

January 30, 2015

By Paul Homewood 


Bill Illis adds some interesting fuel to the debate over temperature adjustments.

As many of you may be aware, I first became aware of this issue in 2012, with the adjustments made in Iceland, such as this one at Reykjavik.




As with all the other sites in Iceland, the GHCN adjustment had effectively removed the inconvenient warm period around 1940, when temperatures were just as high as they have been in the last decades.

In addition, and as a direct result, they also eliminated the extremely cold years of the 1960’s and 70’s, which were so bad that the Icelanders themselves christened them the “sea ice years”, as their Met Office reports:


The 20th century warm period that started in the 1920s ended very abruptly in 1965. It can be divided into three sub-periods, a very warm one to 1942, a colder interval during 1943 to 1952, but it was decisively warm during 1953 to 1964.

The cold period 1965 to 1995 also included a few sub-periods. The so called "sea ice years" 1965 to 1971, a slightly warmer period 1972 till 1978, a very cold interval during 1979 to 1986, but thereafter it became gradually warmer, the last cold year in the sequence being 1995. Since then it has been warm, the warmth culminating in 2002 to 2003. Generally the description above refers to the whole country, but there are slightly diverging details, depending on the source of the cold air.


Many subsequent studies have investigated the cause of the sudden drop in temperature during those years, which were known as “The Great Salinity Anomaly – 1968 to 1982”.

Quite clearly, then, this cold period existed and caused real problems. It was not a measurement error, or a station move, that needed to be “homogenised” out of existence.


However, Bill kept a record of the GHCN adjustment page for Reykjavik, as it was published in February 2014. He compares this with the January 17th and January 29th versions for this year.

The charts can be better viewed by clicking on the links. 



21st Feb 2014




17th January 2015



29th January 2015



If you compare the trend line of the middle graph, on the right (i.e the yellowy thing), there is more than 2C of warming over the full period since 1900. Yet last February there was a lot less than 2C.

The latest trend is even greater than the one GHCN came up with a fortnight ago! In particular, there has been a step up in the warming adjustment during the 1970’s. ( Last year’s version kept the same figure through from 1970.

What this boils down to is that GHCN are making things up as they go along.

They have adjusted historic temperatures, supposedly because they have found anomalies with them, which they assume are wrong. But worse than this is that having adjusted them once, they go back and adjust them again and again.

This makes a mockery of their claim that their homogenisation procedures produce accurate temperature assessments, if they keep having to alter their results.


Apparently, the latest defence of these adjustments from the likes of Kevin Cowton is that they are “calibrating data”. This choice of words is no doubt designed to persuade people that what they are doing is somehow legitimate and accurate. Oxford Dictionary gives this definition of “calibrate”:-

Correlate the readings of (an instrument) with those of a standard in order to check the instrument’s accuracy.

This, most decidedly, is what they are not doing, as they have no means of knowing what the “standard” is. All they are doing is changing the temperature records of places like Reykjavik, without any evidence that they are wrong, and making them match those of other places, maybe hundreds of miles away, on the assumption that:

a) There is any connection or correlation between them

b) That the other places have accurate records. 


The fact that they have now had three different versions of Reykjavik’s record in the last year clearly proves that their “calibration” has no accuracy, and therefore no value.


Meanwhile, the only people who can give a full and proper explanation of what they have done with the Paraguayan stations, and why, are NOAA themselves. I requested this information a week ago, but apart from a standard confirmation of receipt of my request, have had no further response.

I also did the same in 2012, with the Icelandic examples, chased many times, and received many assurances that my request would be answered. Unsurprisingly, NOAA never did come up with an answer.

I won’t be holding my breath this time either.




Bill Illis has kindly added a moving GIF of the three GHCN charts, which shows how they have changed. Concentrate on that middle graph.



  1. Mr_Twister permalink
    January 30, 2015 7:09 pm

    Hello Paul,
    Thanks for the work you do.
    Just wondering (if you view the comments) whether it is possible to incorporate the “Disqus” comments facility into your blog?

    It would send a lot more traffic here, and that would he good for us all, I think.
    Kind regards
    (And in awe) Mr_Twister.

  2. Retired Dave permalink
    January 30, 2015 7:49 pm

    It is just basic fraud – if you did it to some company’s accounts you would go to prison. I still wonder if it might end up that way for some in Climate Science – one can dream.

    I have tried to show some of these adjustments to believers that I know and they think I am some kind of denier person who gets these graphs from some Koch Bros funded trougher or lackey of big oil.

    To save myself some writing I will Cut & Paste from my comment earlier today – –

    “BUT even is worse are the gullible idiots who believe them – they are like the parishioners of that American preacher a couple of years back, who when he told them that the world would end on a certain date, not only believed him: but when it didn’t end on the due date he managed to convinced them that it was just his calculations that were at fault – perhaps he divided by zero somewhere?”

    The problem is that few politicians are interested in the truth – they are either on the Kool-aid, in the trough, or fear attack and loss of power and influence. I remain unsure of how we bring the anti-science mess to an end.

  3. Don permalink
    January 30, 2015 9:33 pm

    Great work guys.

    Smoking gun.

  4. January 30, 2015 10:11 pm

    Paul and Bill, great catch. Could not be a clearer example of continuous undocumented changes that always ‘make it worse’.

  5. Paul2 permalink
    January 30, 2015 10:50 pm

    At the risk of sounding like a stuck record Paul’s work has shown us all that in order to convince people about the scandalous goings on a stand has to be taken by all bloggers and commentators, especially those in the public eye, whereby the soft focus line about Man making some small difference to the climate is replaced with one which says that Man has absolutely no effect on the earth’s temperature.
    This is fundamental if we really want to change the perception of the fools, fraudsters and useful idiots in the mind of the public.
    It’s not for us to prove that there exists AGW but it’s for the scumbags to prove exactly where there has been a change which gives us a chance to dissect and destroy every single example they put forward.
    The line taken so far over the past few years has really, in the end, had very little effect. You only have to see government policy, listen to the cheers of the audience of the useful idiots in discussion programmes like Any Questions and read the garbage that is produced by every single mainstream media outlet.
    We are losing the battle.

    • January 31, 2015 12:34 am

      With all due respect, NO.

      That approach opens you to the Sky Dragon/Principia counter attack.
      Assert that, and the CAGW Consensus will correctly say you understand nothing of radiative physics and are a flat earther. Like Obummer already has said anout all sceptics.

      CO2 is a ‘greenhouse’ gas. Fact, alrhoughmdoes not work physically like a greenhouse. But because of Earth’s feedbacks, we have no idea how much impact it mightl have against a background of strong natural variation. Hence the consensus percautionary primciple. Against which, All the newer energy budget sensitivity evidence says no C . Maybe just a little AGw . Lots od time to figure it out before doing more stupid things. You might benefit from some of the essays in my new ebook on this. Foreward is from Dr. Judith Curry herself.

      • Paul2 permalink
        January 31, 2015 7:46 am

        Yeah well Rud, carry on writing those books for all the good they will do and the minds they will change. We don’t live on Venus – we live on Earth where radiative physics do not apply when it comes to carbon dioxide. Your position is the same as an atheist who tries to convince the gullible as to the existence of God by saying that he believes in God but just a little bit.
        If there is no measurable effect on the Earth’s temperature by rising CO2 levels then there is no Man-made global warming.

      • January 31, 2015 8:52 am

        Surely you still don’t believe in the “greenhouse effect” being the way the atmosphere traps some of the energy we receive from the Sun (infrared radiation or heat, ultraviolet and visible light) and stops it being transmitted back out into space?

      • Paul2 permalink
        January 31, 2015 10:22 am

        @phillipbratby – the greenhouse effect is virtually unaffected by trace gases in the atmosphere. Oceans and land absorb nearly all of the heat from the sun. Ask yourself why scientists are unable to reproduce the effect of carbon dioxide and other “greenhouse gases” in a laboratory unless they pump the chambers they use to demonstrate the effect with so much gas it would be more useful in badger culls than anything else.
        Nope, the greenhouse effect as is understood by most people is a myth.

      • A C Osborn permalink
        January 31, 2015 5:15 pm

        Rud, you need to read this.

        It syas there is an error in the IPCC Feedback for CO2.

      • February 11, 2015 8:49 pm

        AC, I agree. In fact two large errors. Wrote about both in the climate chapter of last book, vetted by Lindzen. Wrote about them again in three essays in new book. Water vapor feedback is too high by roughly and any positive cloud feedback. Both related to an inherent inability to model tropical convection cells owing to grid size computational limits, hence missing Lindzen’s adaptive IR iris. Observational supports from the modeled hot spot that does not exist, and the model underestimate of precipitation by half.

  6. Bill Illis permalink
    January 31, 2015 12:12 am

    I made a Gif animation of the changes.

    Just note the top right panel is the actual quality controlled temperatures from Iceland Met which they insist does not require any further adjustment. The middle panel is what the NCDC reports to the public and the bottom right panel is the adjustments they apply.

    There is no stopping these people without a new law, forensic auditors and a prosecutor.

  7. Bill Illis permalink
    January 31, 2015 12:13 am

    Try again, first time you know.

    • January 31, 2015 12:39 am

      Wish I has been able to put this in the new book. Great smoking gun example. You would have gotten at least footnote recognition like any other paper author. High Regards.

  8. Bloke down the pub permalink
    January 31, 2015 11:28 am

    What this boils down to is that GHCN are making things up as they go along.

    And they’re not the Messiah, they’re very naughty boys.

    • A C Osborn permalink
      January 31, 2015 5:19 pm

      Not just GHCN, NCDC, GISS, BOM, NIWA and HADCRUT as well.

  9. Adam Gallon permalink
    January 31, 2015 6:26 pm

    The “Reykjavik History Problem” has been highlighted several times by Steve Goddard over at Real Science.

  10. William permalink
    February 1, 2015 1:24 am

    Hey Paul, nice work. I’m curious what the numbers at the end of the links mean, for example you have the “after”

    and the “before” (I assume) has the same link but a 1 instead of 12 at the end. I tried a few other numbers and some work. Is there a definition of these number on the NASA site? And did you figure this out yourself or is there a page where you can select before/after/other data?

    • February 1, 2015 11:25 am

      The original GHCN V2 data (which you can access by clicking on it here )gives 3 options:

      Combining sources

      They get suffixes of 0,1 and 2.

      All my graphs are the combined set.

      GHCN v2 only gives data to 2011.

      The current GISS again offers 3 options:

      GHCN Adj
      After removing suspicious records
      Homogenised (this is their adj for UHI)

      My graphs use GHCN Adj

      They get suffixes of 12, 13 and 14

      • William permalink
        February 1, 2015 1:10 pm

        Thanks Paul. I’d seen the page before but somehow I didn’t notice the “Data Set” option 😦

  11. Phil permalink
    February 1, 2015 7:33 am

    Using the new HadISD database, I plotted the temps for Reykjavik for 1973 to 2013. Using the @slope function in Quattro Pro X5, I calculated the slope of a simple linear regression without interpolation as 0.000010049779498.

    Here is the plot:


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