ACT Party leader Rodney Hide alleges state science company Niwa has misled cabinet ministers over New Zealand's official temperature measurements pertaining to global warming.
Mr Hide today opened the scabs on a grievance climate change sceptics have voiced over the scientific integrity of the nation's temperature record which, on average figures from 1931 to 2008 for a core group of 11 measurement sites, shows a trend for the temperature to have risen close 0.92degC over the 78 years.
But the Climate Science Coalition - a lobby critical of the research which shows human activity has caused global warming - has expressed doubt over the consistency of measurements by the National Institute of Water and Atmospheric Research (Niwa), and Mr Hide today alleged Niwa was in breach of statutory obligations to maintain full and accurate records.
"There are heads that should roll in Niwa," he told a Federated Farmers meeting in Hamilton.
He said raw data from a group of seven long-running stations showed no rising or falling temperature trend, except when the data was adjusted by researchers. Niwa has previously explained that its analysis of measured temperatures included internationally accepted adjustments such as for as movement of measurement sites.
In Wellington, early temperature measurements were made near sea level, but in 1928 the measurement site was moved from Thorndon (3m above sea level) to Kelburn (125m above sea level), a site which is on average 0.8degC cooler.
But Mr Hide said Niwa had not been able to supply a "schedule of adjustments" to raw data, had blocked reasonable requests for information, and performed with "reckless disregard" for basic scientific standards.
"They have misled ministers," he said.
Mr Hide's party is opposed to the Emissions Trading Scheme scheduled to take effect on July 1, and has said New Zealand will be the first, and only country to impose a comprehensive scheme on its productive sectors.
He said an official NZ temperature series based on seven measuring sites showed a warming trend of 0.9degC per century, but critics argued that the alarming trend only showed up once the raw data had been adjusted for changes to the environment around the sites.
"Niwa simply did not have a well-organised database, with an accessible or up-to-date or defensible schedule of adjustments," he said.
"These adjustments might be entirely reasonable.
"But we won't know, and can't know, until Niwa is able to publish an authoritative schedule of adjustments."
Mr Hide said Niwa was now conducting a full review of the temperature series, and had said it would publish a complete set of data and documented adjustments.
Niwa's chief climate scientist, David Wratt, was reported in November last year to have said he had no plans to release data backing up claims of different temperature adjustments between historical weather station sites.
