More on the "hockey stick" scandal

Excerpt from Michael Crichton's Senate testimony in September 2005:

...Because any study where a single team plans the research, carries it out, supervises the analysis, and writes their own final report, carries a very high risk of undetected bias. That risk, for example, would automatically preclude the validity of the results of a similarly structured study that tested the efficacy of a drug.

By the same token, any verification of the study by investigators with whom the researcher had a professional relationship-people with whom, for example, he had published papers in the past, would not be accepted. That's peer review by pals, and it's unavoidably biased. Yet these issues are central to the now-familiar story of the "Hockeystick graph" and the debate surrounding it.

To summarize it briefly: in 1998-99 the American climate researcher Michael Mann and his co-workers published an estimate of global temperatures from the year 1000 to 1980. Mann's results appeared to show a spike in recent temperatures that was unprecedented in the last thousand years. His alarming report formed the centerpiece of the U.N.'s Third Assessment Report, in 2001.

Mann's work was immediately criticized because it didn't show the well-known Medieval Warm Period, when temperatures were warmer than they are today, or the Little Ice Age that began around 1500, when the climate was colder than today. But real fireworks began when two Canadian researchers, McIntyre and McKitrick, attempted to replicate Mann's study. They found grave errors in the work, which they detailed in 2003: calculation errors, data used twice, data filled in, and a computer program that generated a hockeystick out of any data fed to it-even random data. Mann's work has since been dismissed by scientists around the world who subscribe to global warning.

Why did the UN accept Mann's report so uncritically? Why didn't they catch the errors? Because the IPCC doesn't do independent verification. And perhaps because Mann himself was in charge of the section of the report that included his work.

The hockeystick controversy drags on. But I would direct the Committee's attention to three aspects of this story. First, six years passed between Mann's publication and the first detailed accounts of errors in his work. This is simply too long for policymakers to wait for validated results.

Second, the flaws in Mann's work were not caught by climate scientists, but rather by outsiders-in this case, an economist and a mathematician. They had to go to great lengths to obtain data from Mann's team, which obstructed them at every turn. When the Canadians sought help from the NSF, they were told that Mann was under no obligation to provide his data to other researchers for independent verification.

Third, this kind of stonewalling is not unique. The Canadians are now attempting to replicate other climate studies and are getting the same runaround from other researchers. One prominent scientist told them: "Why should I make the data available to you, when your aim is to try and find something wrong with it."

Even further, some scientists complain the task of archiving is so time-consuming as to prevent them from getting any work done. But this is nonsense.

Note that Michael Mann is one of the key people behind the realclimate web site.

A quote from Mann:

"We hope this site will serve as a resource that can challenge mis-representations or mis-understandings of the science as they occur in real time," said Michael Mann.

Mann's quote reminds me of Geoff Hill's here:

"We avoid anything that smacks of the lunatic fringe," he says. He doesn't want anyone thinking his desire to see the bird might color his science.

Update: Note that Mann's flawed algorithm produces a "hockey stick" even when fed solar data.