From the "A goat ate my homework" excuse book:

More major embarrassment for New Zealand's 'leading' climate research unit NIWA tonight, with admissions that it "does not hold copies" of the original reports documenting adjustments to New Zealand's weather stations.

The drama hit the headlines worldwide in late November when serious questions were raised about the "adjustments" NIWA had made to weather records. The adjusted data shows a strong warming trend over the past century, whereas unadjusted records had nowhere near as much warming.

NIWA promised to make its data and corrections fully available, but responding to an Official Information Act request their legal counsel has now admitted it cannot provide copies of the original adjustment records.

Now, a news release from the Climate Science Coalition is blowing the NIWA climate scientists out of the water.

The National Institute of Water and Atmospheric Research (NIWA) has been urged by the New Zealand Climate Science Coalition (NZCSC) to abandon all of its in-house adjustments to temperature records. This follows an admission by NIWA that it no longer holds the records that would support its in-house manipulation of official temperature readings. In December, NZCSC issued a formal request for the schedule of adjustments under the Official Information Act 1982, specifically seeking copies of “the original worksheets and/or computer records used for the calculations”. On 29 January, NIWA responded that they no longer held any internal records, and merely referred to the scientific literature. “The only inference that can be drawn from this is that NIWA has casually altered its temperature series from time to time, without ever taking the trouble to maintain a continuous record. The result is that the official temperature record has been adjusted on unknown dates for unknown reasons, so that its probative value is little above that of guesswork. In such a case, the only appropriate action would be reversion to the raw data record, perhaps accompanied by a statement of any known issues,” said Terry Dunleavy, secretary of NZCSC. “NIWA’s website carries the raw data collected from representative temperature stations, which disclose no measurable change in average temperature over a period of 150 years. But elsewhere on the same website, NIWA displays a graph of the same 150-year period showing a sharp warming trend. The difference between these two official records is a series of undisclosed NIWA-created ‘adjustments’. “Late last year our coalition published a paper entitled ‘Are We Feeling Warmer Yet?’ and asked NIWA to disclose the schedule detailing the dates and reasons for the adjustments. The expressed purpose of NZCSC was to replicate the calculations, in the best traditions of peer-reviewed science. “When NIWA did not respond, Hon Rodney Hide asked Oral and Written Questions in Parliament, and attended a meeting with NIWA scientists. All to no avail, and the schedule of adjustments remained a secret. We now know why NIWA was being so evasive - the requested schedule did not exist. “Well qualified climate scientist members of our coalition believe that NIWA has forfeited confidence in the credibility of its temperature recording procedures, and that it cannot be trusted to try to cover up its own ineptitude by in-house adjustments. What is needed is open access in the public domain to all of the known reasons for post-reading adjustments to enable independent climate analysts to make their own comparative assessments of temperature variations throughout New Zealand since the middle of the 19th century,” said Mr Dunleavy.

I kid you not, you could write a book about these shenanigans. ;) If you are interested in reading about the quality of NZ's (and probably the rest of the world's) temperature stations, you could do worse than to read this study by meteorologist Jim Hessell from back in a time before the politics of global warming had encouraged scientists to hide the data.