NIWA’s new NZ temperature series: plus ça change…


Earlier this afternoon NIWA released its recalculated NZ temperature record [full report], and as expected the changes from the “old” seven station series are more or less negligible. The trend over the last 100 years is identical, 0.91ºC per century, as the graph above shows. There are minor differences in some years, and larger ones at some stations, but the net effect to is confirm what we already knew: New Zealand warmed significantly over the last century. Commenting on the new report, NIWA CEO John Morgan said:

“I am not surprised that this internationally peer reviewed 2010 report of the seven station temperature series has confirmed that NIWA’s science was sound. It adds to the scientific knowledge that shows that New Zealand’s temperature has risen by about 0.9 degrees over the past 100 years”.

I’m not surprised either. But I confidently predict that the NZ Climate “Science” Coalition and Richard Treadgold will still find something to whinge about. After all, they’re trying to sue NIWA to have the original seven station series declared invalid. Now it’s been replaced — by something that looks rather similar. Which just confirms how shonky their original complaint and their subsequent silly suit really were. (More on this later, when I’ve had a chance to read the report in detail).

47 thoughts on “NIWA’s new NZ temperature series: plus ça change…”

  1. What a massive surprise!

    I’ll agree with your confident predictions re the local denialists (I keep having this vision of turkeys when I bring them to mind, for some reason…)

  2. Hi Gareth: Thanks for posting this. A good day for real science and confirmation of what many expected. Perhaps we should ask the same reviewers to look at the Treadgold posting? Of course, the usual claptrap about the corrupted peer review process will now get trotted out!

    1. Tenney
      The only reference I found on a quick look was at the bottom of this page.

      “Extensive rehabilitation work has been undertaken on these data to ensure they have not been compromised by changes in site location, urbanisation, exposure or instrumentation over time. These high-quality data series can be accessed at:

    2. I can’t really improve on Adelady’s links, Tenney. The cranks on the other side of the Tasman have been trying hard to pick holes in the BOM record, but don’t seem to have got much mileage out of it. The NZ affair would probably also have died a death if it hadn’t been picked up by the libertarian ACT Party, who are in NZ’s governing coalition.

  3. This received some coverage in today’s DomPost, in a little article tucked away on page A2: “Independent study finds NIWA using sound science on weather”. They don’t seem to have uploaded it to their website. I’d like to see this report used to whack Rodney Hide over the head with at Question Time, metaphorically speaking of course 🙂

    1. Unfortunately, the DomPost has then partially undone the work in the B section, with a piece attributed to “The Times” which they have headlined “Polar bears’ demise reversible, study finds”. In the text of the story you find that “The new projections suggest that if carbon emissions are curbed quickly, enough ice is likely to remain to sustain the current population of polar bears during the next century”.

      At the moment, it doesn’t seem very likely that carbon emissions are going to be curbed quickly (if at all).

  4. Thanks for the post Gareth. Of course no surprise – exactly what I would have expected. Some variation due to the subjective components of working our adjustments but no change to the conclusions.

    But really the media should be giving this far more coverage. No doubt the deniers start producing their press releases claiming a “whitewash” – this may get some coverage then.

    1. They’ve been letting their conspiratorial leanings show — Treadgold seems very taken with Monckton’s fantasies about climate change ushering in world government. Tin foil hat time, to be sure.

      I’d guess that Treadgold is waiting for one of the senior C”S”C cranks to come up with a plausible-sounding complaint about the new series. Good luck with that, all they’ve ever had was the implausible and unreasonable…

  5. Gareth’s “forecast” of further westerly whinging is 100%.
    This time it is Bryan Leyland outrageously and of course without evidence claiming that the seven station series is still statistically invalid. His reason: the Aussie Bureau of Meteorology only did a limited “review” and not a full “re-analysis”. I am guessing Leyland defines a “review” as agreement with the warming trend and a “re-analysis” as disagreement with the warming trend.
    He calls for Minister of Science Wayne Mapp to dismiss the Chair of NIWA, John Morgan. He repeats the “meme” that NIWA have lost the original raw data.
    In other words, the usual, fact-free repetition of denier zombie memes.
    Voxy Call On NIWA To Admit Latest Temperature Review Not Valid
    Scoop Call on NIWA to admit latest temperature review not valid

    And here is the great Treadgold himself. First he interprets NIWA’s confirmation of its temperature record as the exact opposite. According to Treadgold, NIWA has “abandoned” its temperature record. Further – he has been vindicated!
    Climate Science Coalition Vindicated

    I can’t wait for Treadgold and Leyland to publish their paper “While the World warms, NZ temperature has cooled since late 19th Century”

      1. Not like the AGW Team, eh? Dissent has no place among that clutch of snouts! Got to keep that carbon gravy train moving. Never mind the Scientific Method blow torch.

  6. I suppose NIWA wanted to get this out before year’s end. But the interesting parts of the project are yet to come:

    1. The calculations of uncertainty about each adjustment, so the statistical significance (if any) of the new series can be assessed.
    2. The promised NIWA paper describing the rather novel methodology used in the NZT7 for selecting reference sites and assessing them for suitability. Most reference sites are different from those used for the 7SS, so maybe the approach was borrowed from BOM?
    3. The impact (if any) of a new series on a court case asking for the old series to be thrown out.

  7. Yes, aren’t Treadgold and his mates going to look really stupid when this case goes before the court. With the figure above!

    It would be safest for them to cut their losses, withdraw now, and present it as a “victory”!

    1. “Are you guys nuts or what”
      That’s one excuse. There are others.

      “whats happened between 1960 and today”
      Well whadaya know. We’re back down to 1960 levels and heading on down. But you won’t hear that from nutters and scammers.

  8. Interesting to see there has been no warming since approximately 1950. NIWA’s claim that NZ has warmed over the last century is very misleading – warming stopped mid century. As a trend is considered 30 odd yrs, it’s interesting that NIWA omits this point. Another point of interest is that if you look at the old 7SS here:

    NIWA conveniently takes the temperature trend from the lowest point of the record, a record that has approx. 60 years worth of temperature data prior to their starting point. This pre 1910 data also seems to have mysteriously disappeared from the new 7SS. At a rough guess looking at the graph from 1850 onwards, I’d estimate the warming at approx 0.5C, not NIWA’s 0.91C. I wonder if they’ll take their next trend starting point from the peak in 1998’s El Nino? No? I wonder why?

    The new 7 Station Series raises another interesting question – if the 7SS is correct, then how come it doesn’t agree with NIWA’s 11 Station Series with regard to last half of last century. After all, NIWA reassures us that the 11 Station Series must be correct due to none of it’s stations being moved and, as a result, none of it’s data being adjusted.

    One of these series is wrong, is it the 11SS or the 7SS, or both?

    When NIWA submits it work for peer-review via a publication, will they include the full temperature record starting from 1850?

    1. JW-
      There is no mystery to what happened to the pre-1900 data. Read the report. On p. 6 it states: ” The early temperature records are less reliable, and there are very few comparison sites pre-1910 to confidently determine site adjustments. We have not used data prior to 1900, and produced the seven-station average from 1909 onwards.”

      So how is it that you feel justified in making pronouncements about a report you clearly have not read?

      1. Hi Mike,

        This is a 9♣ “Nit Pick

        With nit picking, the denialist finds one problem with a fact asserted or the proposal for reform, and then harps on the problem incessantly.

        Merry Christmas!

  9. JW on what do you base your claim “there has been no warming since approximately 1950”? Are you referring to this latest figure? Have you analyzed the data? Or is that a subjective assessment?

    1. From the report, page 3 (Key Points)

      The variations in time of New Zealand temperature are consistent with completely independent measurements of regional sea temperatures. There is also a strong correlation between variations in New Zealand temperature and prevailing wind flow, which relates closely to the abrupt warming in the mid 20th century, and the slower rate of warming since about 1960.

      So it is not correct that there has been no warming since 1960, but the rate is much less than prior to this date.

        1. So when you wrote “there has been no warming since approximately 1950″ you lied.

          I never made that comment. I believe the exact quote can be attributed to JW here:

          In fact, I went to the effort of (a) asking for the data, (b) plotting it in Excel, and (c) broadly concurring with the rates of temperature rises in first and second half of the 20th Century.

          Never mind, it’s Christmas

          Maybe some more Gammel Dansk is in order?

          1. JW and JD
            Learn to read a graph please.
            Look at the vertical axis… Its the anomalies of temperature year by year.
            “Meteorology . the amount of deviation of a meteorological quantity from the accepted normal value of that quantity.”

            1. Yes, macro, I understand what a temperature anomaly is. How does this affect what I stated previously?
              in fact, how does it affect anything, unless like our driveby friend Lars you intend to be gratuitously offensive. It seems to get the votes so you must be onto something.

  10. “So it is not correct that there has been no warming since 1960, but the rate is much less than prior to this date”.

    Isn’t that rather strange? The IPCC says that greenhouse gas concentrations only became a dominant factor from the late 1970s. So most (maybe all) of New Zealand’s warming was pre-1960 and presumably came from natural forces.

    If the warming pattern of the last 50 years continues on for the next 50, perhaps NZ will entirely escape the effects of global climate change?

  11. Wish they’d take that seriously annoying line out of the graph as it distracts from the data. Looks to me like a step change of about 0.5 degrees in the 1950’s. What happened in the 1950’s? The start of civil aviation perhaps? Tarmac on airport runways?

  12. Ian H, the line displays the regression and is perfectly normal and expected.

    If you read the report you will see a discussion of the temperature increase in 1940-1960. Due to regional wind effects I think.

  13. I know the line is a linear regression. You have some reason to expect the climate to go in a straight line? It never has in the past. So why are you fitting a straight line to it. The line is annoying because it makes it hard to see the real shape of the data.

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