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GISS Make The Past Colder In Reykjavik

January 24, 2012
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By Paul Homewood




Yesterday while finishing off my post “NOAA Don’t Believe The Iceland Met Office”, by chance, I took another look at the latest GISS graph for Reykjavik, which is shown above. It showed, just as it had last week, that the temperature in 2003 was much higher than 1939 and 1941, which as we now know from the Iceland Met Office is not true. However something else looked wrong, that I could not put my finger on.

Fortunately, however, I had kept a printout of last week’s dataset and eventually I realised something else had changed. Effectively the scale had been shifted down, so that every singly year became about a degree cooler.



One can ponder on the reasons for this change, but the consequence is abundantly clear – GISS temperatures for recent years, including 2003, now match the actual temperatures recorded by the Iceland Met Office. (Last week we discovered that GISS/GHCN had adjusted temperatures upwards by about a degree since 1970 – for full story see here). However, as the shape of the graph has not altered, this means that years prior to 1970 are shown as much cooler than they really were.

The changes can be seen by comparing the latest graph with the one below from last week.




Just to put some numbers to this, here is a selection :-

Year Last Week This Week Diff
1911 5.31 4.21 1.1
1941 5.28 4.09 1.19
1971 5.85 4.65 1.2
1991 6.12 4.92 1.2
2011 5.58 5.58 0


GISS no longer have a link to last weeks dataset (not that I can find, anyway), and I have asked for their comments.



I have contacted the Iceland Met Office to get their view on the GHCN adjustments. Their reply could not be clearer :-

a) They were not aware these adjustments were being made.

b) They do not know why they have been made, but are asking!

c) They do not accept the “corrections” and have no intention of amending their own records.

  1. kim2ooo permalink
    January 24, 2012 2:27 pm

    Good Catch!

    OT All my email links to real-science are showing “502 Bad Gateway

    And also from search engines Google – Bing…????

  2. Paul Matthews permalink
    January 24, 2012 3:56 pm

    Ths is getting complicated, with both GHCN and GISS making large undocumented changes.

    I have checked last week’s (20120117) and this week’s (20120123) GHCN adjusted data for Reykjavik, and they are the same. So the change you report here must have been done by GISS, as you say.

  3. Kramer permalink
    January 25, 2012 12:50 am

    It would be nice if the author would use those blinking gifs that show you the before and after every second or so…

  4. SOYLENT GREEN permalink
    January 25, 2012 11:26 pm

    Nice work on the phone call/email to the Met Office.

    That’s priceless.

  5. Dodgy Geezer permalink
    January 26, 2012 2:28 pm

    And quite a nice result. This will make the ‘divergence problem’ much worse…..

  6. Keith Gordon permalink
    January 27, 2012 12:13 am

    Hi Paul, Thanks for your reply to my question on WUWT concerning the adjusted Iceland data.
    Keep up the good work

    Keith Gordon


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