NZ temperature record — it’s worse than we thought

Thanks to those who advised me of this amazing email from the Climategate 2 collection, either through comments here or private email. It concerns the pre-1930 cooling of the New Zealand temperature record, and makes food for thought, especially for those supporting NIWA, Salinger and the increasingly shaky AGW story. Although it’s more of a novel, and a bad one at that, with gaping holes in the plot and evidence so carelessly thrown together it fools nobody. Now, as many of us feared was the case, comes evidence that the NZ temperature record has been applied to far more places than where it was observed. We now know it was stretched over far-flung places it was never intended to go. This is the worst result possible.

date: Mon, 7 Sep 2009 00:13:56 +0100 (BST)
from: “Tim Osborn”
subject: New Zealand summer temps

Hi Phil,

just a quick Q before I go to bed!

I’ve just updated the IPCC paleo chapter Southern Hemisphere plot where we
showed, amongst other things, Ed Cook’s New Zealand TRW reconstruction,
with CRUTEM2v Jan-Mar smoothed temperatures.

For my update I’ve used CRUTEM3v, expecting them to be rather similar but
with a few more years on the end.

But the pre-1930 temperatures are now very different, being much cooler
(by > 0.5 degC for a 25-year low-pass mean) in CRUTEM3v than CRUTEM2v.
Previously they had been, on average, near or even above the 1961-1990
mean, now they’re at -0.5 degC.

Is this a result of some homogenization work on New Zealand summer temp
data? Or just some random artefact of minor changes somewhere?



— Dr. Tim Osborn RCUK Academic Fellow Climatic Research Unit School of Environmental Sciences University of East Anglia Norwich NR4 7TJ, UK

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11 Thoughts on “NZ temperature record — it’s worse than we thought

  1. Australis on 01/02/2012 at 7:55 pm said:

    CRU staff noticed that somebody had tampered with New Zealand’s temperature record, by reducing the early 20th-century levels by more than 0.5 deg.

    This tampering introduced a major bias into the trend – also more than 0.5 deg.

    Presumably, the only person with the authority to make this change would be Phil Jones himself. Yet he was also responsible for CRUTEM2v which was based on Ed Cook’s published reconstruction of NZ temperatures. And for the IPCC graphs based on CRUTEM2.

    It must have taken a strong case to change Phil’s mind on something this important. Who made that case? Where is it recorded? Did he respond to Osborn’s email?

  2. Huub Bakker on 02/02/2012 at 5:32 am said:

    I had a quick look through the Climategate 2 emails and found this one, 0279, written a few days later. Where did yours come from Richard, Climategate 1?

    There are obviously several missing in between; maybe in the encrypted annex to Climategate 2?

    date: Mon, 14 Sep 2009 16:14:30 +0100 (BST)
    subject: Re: new zealand temps: crutem2 to crutem3
    to: “Tim Osborn”

    Maybe you should see David if he can recall making any changes to land
    stations over NZ – and if so when? There might have been changes
    immedaiately after Jones and Moberg (2003) that Harry wasn’t aware of.
    Another thought is to check whether your programs work with CRUTEM2 as
    of now. CRUTEM2 data are on the CRU site, go to the temp page and they
    are near the bottom.


    > Phil, I had a look at figure 1 of Brohan et al. showing land station
    > coverage and coloured dots for new/deleted/edited stations. All in
    > New Zealand are black, implying no change from CRUTEM2! I’ll check
    > with programs again in case I screwed up, but fairly confident I
    > didn’t — so its rather confusing as to why CRUTEM2 and 3 are so
    > different over New Z. in summer. Tim
    > At 21:27 11/09/2009, you wrote:
    >> Tim,
    >> This one would be good enough. I don’t know if it is the right one.
    >> We also got some additional NZ stations as well.
    >> It is more about exposures in Australia – that cause the pre-1910 data
    >> to be less good.

    >> For NZ, it is more work on the early NZ data. Exposures would be a
    >> problem, but before about 1880. There was a gap in much NZ data during
    >> the 1870s. It may be that we had only a couple of sites for V2, but got
    >> several more for V3.
    >> Cheers
    >> Phil
    >> > Hi Phil,
    >> >
    >> > I’m wondering how best to explain the cause of the change in New Zealand
    >> > summer temps from crutem2 to crutem3. I could just say that crutem3 uses
    >> > differently (or better?) homogenised stations records from some locations
    >> > (could I say that the homogenisation adjusted for 19th century exposures
    >> > being different?), with a pers. comm. to you. But if there’s a reference
    >> > for homogenised New Zealand data, that would be better. I saw this one,
    >> > by Jim Salinger that mentions “newly homogenised SW Pacific data” and
    >> > includes New Zealand. Would this be what you now use?
    >> >
    >> > Salinger MJ (1995)
    >> > Southwest Pacific temperatures: trends in maximum and minimum temperatures
    >> > Atmospheric Research
    >> > Volume 37, Issues 1-3, July 1995, Pages 87-99
    >> > Minimax Workshop
    >> >
    >> > doi:10.1016/0169-8095(94)00071-K
    >> >
    >> >
    >> >
    >> > Though I can’t download the PDF from home to see what it says.
    >> >
    >> > Tim
    >> >
    >> > —
    >> > Dr. Tim Osborn
    >> > RCUK Academic Fellow
    >> > Climatic Research Unit
    >> > School of Environmental Sciences
    >> > University of East Anglia
    >> > Norwich NR4 7TJ, UK
    >> >
    >> >
    >> >
    >> >
    >> >
    > Dr Timothy J Osborn, Academic Fellow
    > Climatic Research Unit
    > School of Environmental Sciences
    > University of East Anglia
    > Norwich NR4 7TJ, UK
    > e-mail:
    > phone: +44 1603 592089
    > fax: +44 1603 507784
    > web:
    > sunclock:

    • It comes, according to my impeccable academic source, from Climategate II.

      I regret I can scarcely keep up with my inbox at the moment, much less research anything, so I must leave this to others for now.

      But I note: “This one would be good enough. I don’t know if it is the right one.”

      A cavalier attitude to science, indeed.

    • Richard C (NZ) on 02/02/2012 at 2:17 pm said:

      Salinger 1995 has this:-

      “Fig. 3. New Zealand temperature response areas and stations used in this study (after Salinger, 1979).”

      That’s for the T3 region, so the data up to 1979 would not have changed between 1979 and 1995 presumably.

      What date was the CRUTEM2 to CRUTEM3 changeover?

  3. Alexander K on 02/02/2012 at 8:04 am said:

    Richard T
    When one is searching for pre-determined measurements to support a particular scenario, knowing whether anything is ‘the right one’ is irrelevant.
    ‘Cavalier’ is too mild a description for this chicanery: ‘totally dishonest’ is nearer the mark for me.

    • Andy on 02/02/2012 at 10:10 am said:

      Reading the Climategate emails, I get the impression of a bunch of guys preparing material for a marketing presentation rather than engaging in what we know as science.

  4. Gidday Kiwis – great post.
    I reported this in May 2007 – so it took Tim Osborn 2 yrs to wake up.
    See my blog post – “Hadley Centre inserts more warming into New Zealand climate history”
    Some answers to questions above – the Jones et al CRUT2 ended in 2005 and used pretty much raw NZ data.
    The higher warming CRUT3 is a creature of the UK Met Office – Hadley Centre – and has inhaled versions more NIWA friendly. Jones was listed as the last author on that paper Brohan et al 2006.
    I wonder who the David is – ref the 14 Sep 2009 email above from Phil Jones – possibly Parker I suppose.

  5. I should have added that CRUT3 is a misleading term IMHO – should have been HadT3 or UKMOT3

  6. Richard C (NZ) on 08/02/2012 at 6:44 pm said:

    Clive Best on CRUTEM3:-

    Can empty grid points similarly affect the anomalies? The argument against this, as discussed above, is that we measure just the changes in temperature and these should be independent of any location bias i.e. CO2 concentrations rise the same everywhere ! However it is still possible that the monthly averaging itself introduces biases. To look into this I calculated a new set of monthly normals and then recalculated all the global anomalies. The new monthly normals are calculated by taking the monthly averages of all the stations within the same (lat,lon) grid point. These represent the local means of monthly temperatures over the full period, and each station then contributes to its near neighbours. The anomalies are area-weighted and averaged in the same way as before. The new results are shown below and compared to the standard CRUTEM3 result.

    Fig5: Comparison of standard CRUTEM3 anomalies(BLACK) and anomalies calculated using monthly normals averaged per grid point rather than averaged per station (BLUE).

    The anomalies are significantly warmer for early years (before about 1920), changing the apparent trend. Therefore systematic errors due to the normalisation method for temperature anomalies are of the order of 0.4 degrees in the 19th century. The origin of these errors is due to the poor geographic coverage in early station data and the method used to normalise the monthly dependences. Using monthly normals averaged per lat,lon grid point instead of per station causes the resultant temperature anomalies to be warmer before 1920. Early stations are concentrated in Europe and North America, with poor coverage in Africa and the tropics. After about 1920 these systematic effects disappear. My conclusion is that anomaly measurements before 1920 are unreliable, while those after 1920 are reliable and independent of normalisation method. This reduces evidence of AGW since 1850 from a quoted 0.8 +- 0.1 degrees to about 0.4 +- 0.2 degrees

  7. I have not yet digested the Clive Best article – however seeing the question “Can empty grid points similarly affect the anomalies?”
    I was reminded of my report into bogus warming claims in the “Northern Siberia, Taymir Peninsular Region”.
    there I found that empty 5 degree grid cells can certainly be assigned more warming than you would expect from surrounding stations.
    Or as I put it then;
    [2] Interpolations of data to grid cells devoid of stations ends up with higher warming trends than the parent data ???

    At the time I emailed Phil Jones about this – he wriggled out of an explanation by saying there was a new paper coming out which explained all. For the IPCC Glitterati there is always a new paper coming out. Other standard Phil fend-offs were, “just arrived back from somewhere” – and “just rushing off to somewhere”.

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