New Zealand’s climate change deniers’ distortions exposed.

I am pleased to see that the attempt to promote a New Zealand version of “climategate” has more or less foundered. Sure the ACT party and some more extreme opponents of the findings of climate scientists are still campaigning (see for example Auckland Public Meeting: Climategate, NIWA and the ETS). And well know local climate change denier Ian Wishart managed to get international reporting of his slanderous press release (BREAKING: NZ’s NIWA accused of CRU-style temperature faking) in several more conservative and extreme international blogs and papers (for example BREAKING: NZ’s NIWA Accused of CRU-Style Temperature Faking, Climategate Scandal Spreads to New Zealand as MSM Continues Ostrich Act, Oops! Now New Zealand NIWA Accused Of Faking Data, New Zealand’s NIWA Gets Busted “Tricking” Their Climate Data and New Zealand Climate Data Shows Clear Evidence Of Fraud). But the New Zealand media has, in general, been more balanced in its reporting. The information from climate scientists at NIWA has been getting through.

Temperature trends for raw data

For example, NIWA’s information on the temperature trends shown by raw data from 11 local  met stations (Temperature trends from raw data) has been picked up (Niwa publishes climate data to answer critics). NIWA released this because of the distorted information distributed by the NZ Climate Science Coalition, the Climate Conversation Group and Ian Wishart (Climate change deniers live in glass buildings ).

Some local bloggers picked up and reproduced this misinformation. In the process they have been slandering our local climate scientists and other bloggers who have attempted to correct the misinformation. My personal concern in this is not so much the facts of climate change, but the willingenss of some ideologically driven people to unjustly attack the integrity of honest scientists. And their willingness to distort information with this end in mind.

So it’s worth reproducing some of the latest information released by NIWA.  This uses publicly -accessible information (from the National Climate Database). The data used is from the period after 1930 when there were no significant site changes. Consequently the raw data could be used without adjustments to determine temperatures at the individual sites. (You will recall that the climate change denier’s report and press release claimed that NIWA’s adjustment of data to accommodate met station site changes was fraudulent. And that they (the deniers) went ahead to combine data without adjustments and produced a misleading graphic suggesting temperature was unchanged over time. The current data should avoid all issues of adjustments).

NIWA’s information says in part:

We have analysed raw data from these sites directly, with absolutely no adjustments to the numbers from the NIWA climate database. Taking all sites together and averaging the annual mean temperatures (difference from 1961–90 mean at each site) results in Figure 1 below.

Graph of 11-site temperature record for NZ

Figure 1: Temperature departures from the 1961–90 normal, averaged over the eleven sites listed in Table 1. For years where not all sites are available, the average is over those that do have records.

Note that not all stations have annual mean temperature values for all years in 1931–2008. It is common practice to in-fill isolated missing months, but we have deliberately not in-filled missing data here to keep this analysis as non-contentious as possible. For each year, the available station values have been averaged. In the title of the Figure, the “p-value” comes from a statistical test, and indicates the probability that the indicated trend could have arisen by chance.

If the two outlying Island records (Raoul and Campbell Islands) are left out, and the remaining nine records averaged, the result is as shown in Figure 2. In either case, the trend over the 78 year period is close to 1°C.

NZ temperature trend using raw data from 9 stations

Figure 2: Temperature departures from the 1961–90 normal, averaged over the nine sites listed in Table 1 that are located on the main islands of New Zealand (i.e., all but Raoul and Campbell Islands). For years where not all sites are available, the average is over those that do have records.

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45 responses to “New Zealand’s climate change deniers’ distortions exposed.

  1. Hopeless Perrot, absolutely hopeless. Can you personally explain the legitimate statistical justification for attributing airport temps to Thorndon?

    No, thought not. I suspect your direct knowledge of climate science could be encapsulated on the back of a postage stamp.

    In the absence of a proper study of two sites, any adjustment between the two made by NIWA was merely guesswork, and not educated guesswork.

    Yet NIWA stated this was international best practice. This statement staggered many scientists overseas, and points to a bigger problem in the surface temperature records – if climate “scientists” think that torturing data in this way is legitimate, then we are in big trouble.

    NIWA’s press release in its defence was a bigger scandal than the initial climate science coalition document. That’s why the world reacted to it.

    And here’s something else for you to explain: NIWA is on the official record as saying NZ will experience a smaller temp rise because the large ocean expanse cools us more effectively. So how on earth has NIWA come up with a 0.92C warming trend that is 50% higher than that found by the UNIPCC?

    Hadn’t considered that one either, had you.


  2. This statement staggered many scientists overseas, and points to a bigger problem in the surface temperature records.

    Bat guano.
    Get your facts straight.
    The scientific community fully supports the efforts of NIWA.
    You have nothing.

    If the deniers have anything to say they should grow a pair and enter the scientific arena.
    Deniers hardly ever do any actual work.
    They are lazy and intellectually dishonest.
    They just sit around and fart on their no-name blogs while real scientists do the heavy lifting.


    “There’s been a whole lot of work behind this in terms of things like having overlaps between particular stations when they’ve moved. There’s a whole methodology, internationally accepted, where you actually work out how to correct for these sorts of site changes and so on.”

    “But you’ll be providing all that shortly?”

    “Well, we’re not going to run around in circles just because somebody has put out a press release. We will continue to put out what is reasonable to provide.”

    “Wouldn’t it be important –“


    “…for people to see the comparison studies between both sites?”

    “Look, we’re talking about scientific studies here. I’ve told you we’ll put out information about Wellington. Basically it’s not up to us to justify ourselves to a whole lot of people that come out with truly unfounded allegations. We work through the scientific process, we publish stuff through the literature, that’s the way that we deal with this stuff and I can’t have my staff running around in circles over something which is not a justified allegation. The fact that the Climate Science Coalition are making allegations about my staff who have the utmost integrity really really pisses me off.

    “That’s all I’ve got to say to you now – [click]”

    Dr David Wratt sounds like he doesn’t suffer fools gladly.


  3. Calm down Ian. You didn’t read this post, did you. It’s referring to raw data without combination of data from separate stations. No adjustment factors.

    So your argument is even more irrelevant here than I’m your comments on the fraudulent combination of seperate stations in your press release.


  4. Pingback: Brad Heap » Blog » Climategate. Yeah Right.

  5. Pingback: New Zealand’s climate change deniers’ distortions exposed. | Open Parachute

  6. The only bat guano around here is what passes for Ken’s posts, and your analysis Cedric.

    Ken, if you were bright enough to understand my point you wouldn’t have made your statement above. The raw data is irrelevant to the point I was making: NIWA got caught making dodgy adjustments to the Kelburn/Thorndon mix.

    I am extremely interested in the logic and methodology behind the adjustments they DO make, more so in fact than I am in the size of the warming trend they claim.

    If the process is correct, we can trust the data and the people behind the data. If the process is invalid, as it was in the NIWA Wellington release, and that invalidity is repeated elsewhere because of bad methodology, the story becomes bigger again.

    As for NIWA’s Kelburn trend, UHI would appear to be a culprit based on the photos of the Kelburn site.

    Incidentally, you failed to answer my challenge as I knew you would. Didn’t have the right postage stamp immediately to hand?