A court challenge to the validity of the New Zealand temperature record [NZTR] has concluded. The Judgement refused all three parts of the challenge to the NZTR.
The challenge had been initiated by a group of climate researchers called The New Zealand Climate Science Education Trust [the Trust] against the government funded scientific body which prepared the NZTR, the National Institute of Water and Atmospheric Research LTD [NIWA].
The Trust issued a Statement of Claim [SOC] seeking:
A declaration that the New Zealand Temperature Record is not a full
and accurate record of changes in the average surface temperatures
recorded in New Zealand since 1900.
The Trust supported this claim on the basis of a pronounced difference in the temperature trend from the raw temperature data at the seven sites used to produce the NZTR and the trend after adjustment by NIWA. When enquiries were made to NIWA for an explanation the Trust was referred to a 1993 paper by Rhoades and Salinger [RS93], a leading statistician and climate researcher respectively, which provided criteria for adjusting raw temperature data.
When the Trust applied the criteria for adjusting temperature from RS93 they found the adjusted trend was still much less than the trend used by NIWA:
|Rhoades & Salinger method||0.34|
It should be noted that there are cogent reasons for adjusting raw temperature data. In an entertaining paper by Torak some of the reasons for adjusting were compiled and can be viewed at Table 2.2; they included the involvement of beer in the data collection process, unruly birds and other wildlife, inferior readings by women and a suspicion that readings were exaggerated because extra rations were given if the temperature went over 100°F.
However, the challenge against the NZTR was not about the need for adjusting the temperature record but that the official criteria for adjusting the temperature was not followed by NIWA.
The Defence filed by NIWA asserted that the NZTR was not a public or official record. The NZTR was only for research purposes. The Defence distinguished between the data from the official temperature sites which it admitted was a public resource and the NZTR record which it claimed was not a public resource.
In response to the Defence an amended SOC was filed. The amended SOC considered the 2010 review by NIWA of the then 7 official temperature sites and the replacement of those by a new 11-site-based temperature record in 2009. The amended SOC noted at paragraph 41:
The data and calculations used in the Review Report, in particular
the adjustments made to the raw temperature data, differ markedly
from those utilised in producing the 7SS. Notwithstanding these
significant changes the NZT7 shows a coincidental, and for the
reasons set out below a scientifically untenable, century-long
warming trend similar to that shown in the 7SS.
In effect NIWA had replaced the old temperature network and employed a new and/or revised adjustment process and criteria and still found approximately the same temperature trend.
In his Judgement Venning, J. allowed the challenge in principle because NIWA was a Crown research Institute [CRI] and no other method of challenging it was available. In effect while Venning, J. agreed the NZTR was not a public record [paragraph 38] the Public had a right to challenge actions of NIWA such as producing a NZTR.
However Venning, J. dismissed that right to challenge on the basis of criteria outlined at paragraph 47 of his Judgement:
I consider that unless the Trust can point to some defect in NIWA’s decision-making process or show that the decision was clearly wrong in principle or in law, this Court will not intervene. This Court should not seek to determine or resolve scientific questions demanding the evaluation of contentious expert opinion.
The error “in principle or in law” which the Trust tried to establish was that NIWA did not adjust temperature according to its own criteria as described in RS93.
NIWA’s own expert witnesses admitted that they did not follow the RS93 criteria in a 2010 “Review” of the NZTR [paragraph 147] but had done so in forming the original NZTR which had been changed in 2009 from a 7-site network into an 11-site network which in turn was reviewed on the basis of other unspecified criteria for adjusting the raw data.
NIWA’s expert witnesses stated it did not matter what criteria they used to adjust the raw temperature data or what sites they adjusted the data from because the temperature trend results were the same as the trend produced by the RS93 adjustment criteria [paragraphs 148-149].
To double-check that the alternative method[s] of adjusting the raw temperature data produced the same temperature trend as the RS93 criteria for adjusting would have done if used in the 2010 “Review” NIWA’s experts did apply RS93 to the 2010 Review of the NZTR sites [paragraph 144]. The NIWA experts concluded that the Trust expert witnesses had been incorrect when they applied RS93 to the raw data and found a lesser trend than found by NIWA when it applied both RS93 and the other adjustment criteria.
This thoroughness by NIWA in checking its own adjustment procedures was approved by Venning, J. who concluded at paragraph 157:
I accept that NIWA could have recalculated the temperature adjustments in a different way yet still have arrived at a similar result which would strengthen the robustness and validity of the previous results.
Venning, J. could do nothing other than accept the statements of the NIWA experts because earlier he had dismissed the expertise of the Trust witnesses [paragraphs 49-54].
However, in accepting that NIWA could produce the official trend of 0.91°C from different adjustment methods Venning, J. provided legal interpretation of two principles of the AGW debate.
The first is that experts working for government or ‘official’ scientific institutions [CRIs] are given greater evidentiary weight than witnesses not working for CRIs. On this basis the authority of the AGW science has been judicially endorsed.
Secondly, at paragraph 80, Venning J. elaborates on the issue of “officially recognised scientific opinion.” Venning J. recognises NIWA’s expert opinion that in respect of temperature adjusting and climate matters generally, there is no one “immutable” standard and indeed could not be.
NIWA’s adjustments of temperature are, therefore, essentially subjective in nature, and, like the definition of “excellence” which the Trust claimed was the standard to which NIWA should be held accountable, not “readily susceptible to judicial assessment” [paragraph 74]. What the courts will do, as Venning J’s judgement shows, is give considerable discretion to CRIs in their preparation of temperature networks and trends by adjusting raw data.
This discretion extends to subjective aspects of temperature adjustment where the institution can choose the method to adjust temperature data regardless of other methods and criteria; and in matters of fact where the institution has used or not used a method of adjustment of temperature data the institution is the preferred authority for concluding the fact of what it has done. On this basis the AGW science has been judicially settled.
New Zealand case law is not binding on other Commonwealth jurisdictions like Australia, but still persuasive.
In Australia the Bureau of Meteorology [BOM] compiles the Australian temperature network in a similar fashion to NIWA, by adjusting raw data. BOM has just replaced its old High Quality temperature network [HQ] with a new network, ACORN. BOM did this because it recognised problems with the HQ network which possibly made it inaccurate. ACORN has supposedly rectified those inaccuracies but has still produced a similar temperature trend to the HQ network. ACORN was peer-reviewed by a panel of climate experts including NIWA representatives.
However, based on the New Zealand temperature case, any questions raised from outside the government scientific institution, BOM, especially from sources which the court does not recognise as being “officially recognised scientific opinion”, are unlikely to have much credence given to them by judicial appraisal.