Jennifer Marohasy

Individual temperature proxies — tree rings, lake sediments, ice cores and the rest that can take us back one thousand years and more — they never ever look like a hockey stick; that requires their complete remodelling. The distinctive shape suggesting catastrophic human-caused global warming emerges only after the data are combined through particular choices of standardisation, principal-component analysis and weighting, and on it goes etcetera, etcetera.

A clear illustration is the long bristlecone-pine ring-width series from the White Mountains of California. The same region supplied chronologies that formed part of the multi-proxy network used in the original Mann et al. reconstructions that underpin official understandings of climate change.

When the raw data are plotted as twenty-year averages (as Hubert Lamb himself published them in Climate, History and the Modern World, 1982), they show large multi-century swings, not a flat shaft ending in a sharp modern blade.

Those who want to deny this, worse those who I would like to discuss this with, in position of influence and authority, but deny me their time of day. Well, shame on you. I will not be silenced, or shamed, not going forward, not ever

Tim adds:

Michael Mann used just three trees at Yamal to help him plot out his hockey stick graph because only those three trees showed the temperature rise he was seeking. The others did not. This is what the Climategate e-mails mean about "hide the decline"; Mann was trying to hide the decline in a warming trend he was trying to create.

That is why Mann spliced temperature station measurements onto his proxy data sets. Mike's Nature trick.

Tim Kinnan also makes a great comment:

Ah yes - good discussion of the hockey stick graph, which Al Gore used to scare the naive in his stupid climate movie. Here is a discussion of the origins of Michael Mann’s infamous hockey stick, provided by Rupert Darwall:

The "Hockey Stick Graph” was Michael Mann’s attempt to reconstruct global temperature over the previous millennium. The graph shows global temperatures purportedly falling for centuries and suddenly shooting upwards with the advent of the Industrial Revolution. Mann’s hockey stick representation was derived principally from selected tree ring data. The results that Mann produced are also sensitive to decisions on and application of statistical techniques.

In 2001, the hockey stick was given star billing in the Intergovernmental Panel on Climate Change’s (IPCC) Third Assessment Report, where it appeared twice in the synthesis report, twice more in a diagram combining past and future temperature change, and again on the third page of the Working Group I Summary for Policy Makers. Gerald North, a leading atmospheric physicist at Texas A&M University and one of the most cited authors in the geosciences, had no doubt as to the significance of the hockey stick. "The planet has been cooling slowly until one hundred and twenty years ago, when, bam! It jumps up,” North told Science in 2000. For Mann, the hockey stick was his ticket to climate super-stardom.

Mann’s hockey stick aroused criticism from its first appearance. In response, Mann engaged in efforts to suppress all criticism of the hockey stick and discussion of rival temperature reconstructions that might raise awkward questions about its scientific validity. A rival reconstruction by fellow paleo-climatologist Keith Briffa, for example, derived from tree ring data obtained from northern Canada and Siberia, showed a noticeable decline in temperatures over the latter part of the 20th century – opening up a divergence with the instrumental record. If tree rings suggested declining temperatures when temperatures were actually rising, then how could climate scientists put any confidence in tree rings as thermometers? Up could really mean down.

Briffa then wrote a paper for Science comparing the rival reconstructions. As we know from the Climategate emails leaked in 2009, Mann contacted the editor of Science. "Better that nothing appear, than something unacceptable to us,” he wrote, copying in one of his co-authors, Raymond Bradley. After Science published Briffa’s paper, Mann tried to patch things up. "Thanks for all the hard work,” he emailed colleagues. The sentiment didn’t go down well with Bradley. "Excuse me while I puke,” Bradley emailed Briffa.

Such shenanigans are small beer compared to the surgery undertaken on the graphs of proxy reconstructions showcased in the IPCC’s Third Assessment Report. To deal with Briffa’s question-inducing temperature decline, Mann, as lead chapter author, and a tight-knit team resorted to the simple expedient of truncating adverse data that could serve as a "potential distraction/detraction,” Mann explained to his colleagues, and thereby hiding the temperature decline shown by Briffa’s proxies when temperatures were rising. The gambit also involved using actual temperature data to smooth the proxy curves in what became known as "Mike’s Nature trick,” something Mann had done previously in a paper submitted to that journal.

There was a more fundamental problem with the construction of the hockey stick. Analysis conducted by Canadians Steve McIntyre, a former mining engineer with a strong grounding in mathematics, and environmental economist Ross McKitrick using an algorithm based on a fragment of Mann’s computer code, found that running statistically trendless "red noise” produced hockey stick shapes 99 percent of the time. In other words, you could get hockey sticks from random junk data if you had enough of it.

Mann included in his proxy data set a series of bristlecone and foxtail pines from the western United States that had been selected by researcher Donald Graybill to study the possible effects of carbon dioxide fertilization on tree growth. To get the hockey stick from the data, Mann needed both the algorithm and Graybill’s tree ring data. Did Mann know what he was doing? Inside his directory of North American proxy data, Mann had a folder which he had labelled BACKTO_1400-CENSORED containing the North American data except all sixteen of the Graybill series. When the numbers from the CENSORED folder were run, the blade of the hockey stick disappeared.

There were other issues with the chart. What previous generations of climatologists called the Medieval Warm Period had disappeared.

In written congressional testimony in 2011, the climate scientist John Christy recalled discussions on the preparation of the Third Assessment Report when he pressed for inclusion of the findings of a 1998 paper in which Greenland ice-borehole temperatures provide a 20,000-year reconstruction. "Their result indicated a clear 500-year period of temperatures, warmer than the present, centered about 900 AD,” Christy testified. Despite – or, perhaps, because – of the importance of the paper in contradicting the hockey stick, the Third Assessment Report ignored the paper altogether.

Mann went further in a 2008 paper that presented a 2,000-year temperature reconstruction. In this reconstruction, it was obvious that warming became cooling and cooling became warming. Was this done on purpose or by mistake? "It has been turned upside down twice in Science, and now I doubt if it can be a mistake any more,” Saarnisto said, adding that the authors belong to a group "skeptical about this Medieval Warm Period and have tried to hide it.”

***

In response to questions about his methods, Mann sued two reporters for defamation. He claimed that Simberg and Steyn describing Mann’s hockey stick as fraudulent, which they did. A jury imposed just $1,000 in punitive damages on Simberg but $1 million – one thousand times more – on Steyn. (The jury awarded Mann a dollar each from Simberg and Steyn to compensate him for damage to his reputation.) The massive differential in punishments the jury meted out to the two defendants can only be explained by the jury’s political bias. Steyn has a high profile as one of the most accomplished of conservative commentators. Evidently, the DC jury decided to make an example of Steyn and discourage any public questioning of today’s consensus of human-caused climate change.

In his opening statement, Steyn argued that it is not for the courts to adjudicate science. "A scientific theorem that requires validation by a courtroom verdict is not science at all,” Steyn argued. In principle, a court should be able to assess whether evidence used to make a scientific claim has been knowingly distorted, omitted, concealed or, in some other way, manipulated to produce a desired result. After all, fraud is not limited to theft but includes the tort of fraudulent misrepresentation.

Mann’s lawsuit demonstrates that the courts – at least, a court in the nation’s capital with politically biased jurors – are not capable of objective evaluation. Such cases also involve federal rules on the admissibility of evidence proffered by expert witnesses and the Daubert standard for scientific evidence. In a 39-page report, climate scientist Judith Curry gave her opinion that it is "reasonable” to have referred to the hockey stick in 2012 as "fraudulent” in the sense that "aspects of it are deceptive and misleading.” Since then, a Superior Court judge reversed the ruling, and ordered Mann to pay over half a million dollars in legal fees.

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