A group of global warming sceptics has dropped a court challenge against the National Institute of Water and Atmospheric Research over national temperature records.

The New Zealand Climate Science Education Trust had taken the crown research institute to court after arguing that the way it collected records was unscientific and unreliable.

The dispute centred on readings from the seven-station series - stations in Auckland, Masterton, Wellington, Nelson, Hokitika, Lincoln and Dunedin - used by Niwa for temperature records.

The trust claimed unscientific methods used created an unrealistic indication of climate warming.


But last year, High Court Justice Geoffrey Venning ruled against the group and ordered it to repay court costs. The group decided to challenge the ruling in the Court of Appeal, but this week withdrew the appeal.

Barry Brill, who acted as solicitor for the trust, said his clients could not see a way forward after coming upon a procedural issue. The judges had noted two scientists involved in the reports were not cross-examined - something his clients were unaware could be done during the earlier court process. But the group's argument stood and it might find another forum to challenge the records.

Niwa chief executive John Morgan said he was pleased but not surprised by the outcome. "We never doubted the excellence and integrity of our science and our scientists," he said. "The methodology applied by Niwa was in accordance with internationally recognised ... methodology."

A decision on the costs related to an appeal hearing this week is still pending.

Climate scientist Dr Jim Salinger, closely involved in producing the disputed series, said judges had ruled against cases brought by climate sceptics in the past and believed such an appeal would have been "extremely unlikely" to succeed.