Obvious questions about the hockey stick graph

This guy doesn't question the underlying temperature measurements, just how different data sets were combined.

A key piece of evidence in climate change science was slammed as “exaggerated” on Wednesday by the UK’s leading statistician, in a vindication of claims that global warming sceptics have been making for years.

Professor David Hand, president of the Royal Statistical Society, said that a graph shaped like an ice hockey stick that has been used to represent the recent rise in global temperatures had been compiled using “inappropriate” methods.

“It used a particular statistical technique that exaggerated the effect [of recent warming],” he said.

The criticism came as part of a report published on Wednesday that found the scientists behind the “Climategate” e-mail scandal had behaved “honestly and fairly” and showed “no evidence of any deliberate scientific malpractice”.

The e-mails were hacked last autumn from the Climatic Research Unit at the University of East Anglia. They caused a storm, as they appeared to show scientists manipulating and concealing data.

Although Wednesday’s report – commissioned by UEA with advice from the Royal Society, the UK’s prestigious national science academy – exonerated the unit’s scientists, it criticised climate experts for failures in handling statistics.

“It is very surprising that research in an area that depends so heavily on statistical methods has not been carried out in close collaboration with professional statisticians,” the report concluded.

The hockey stick graph was a key part of the scandal. In the e-mails, UEA’s Professor Phil Jones referred to a “trick” to “hide the decline” in temperatures suggested by certain sources of data. A similar trick was used in the hockey stick graph.

The UEA scientists said that “trick” merely referred to a scientific technique – an explanation accepted by some sceptics, including Lord Lawson, former Tory chancellor. . . .