AGW law: New Zealand judgement day

A court challenge to the validity of the New Zealand temperature record [NZTR] has concluded. The Judgement refused all 3 parts of the challenge to the NZTR.

The challenge had been initiated by a group of climate researchers called The New Zealand Climate 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 7 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:

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.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 100F.

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.