We need to remember what science is it is not a compilation of facts. Rather it is a set of processes used to gather relatively reliable information about the world we live in, our societies and ourselves. It is the formality of these processes that gives science its privilege and validity over other claims to knowledge about our world that can only come from belief, received wisdom, or anecdote. When this formality is broken whether by unsupported claims , hidden biases , lack of reproducibility , and inadequate peer review public trust in science is harmed and its privilege is undermined.
PROFESSOR SIR PETER GLUCKMAN, ONZ, KNZM, FRS, FMEDSCI, FRSNZ ARTHUR E MILLS MEMORIAL ORATION TO THE ROYAL AUSTRALASIAN COLLEGE OF PHYSICIANS, MAY 18TH 2014 P ETER GLUCKMAN is the Chief Scientific Advisor to the Government of New Zealand, and broadly supportive of the general line on "climate change”. His emphasis on the formality of scientific processes is not contentious, and his list of breaches in that formality and their harm to public trust is worth considering with respect to Michael E Mann and his work:
1) Unsupported claims In the Summary for Policy Makers of its Third Assessment Review, the Intergovernmental Panel on Climate Change made the single most dramatic assertion in the history of the global-warming movement: The increase in temperature in the 20th century is likely to have been the largest of any century during the past 1,000 years. It is also likely that, in the Northern Hemisphere, the 1990s was the warmest decade and 1998 the warmest year. The only evidence offered in support of this statement was Michael Mann’s hockey stick. Does it, indeed, support such a claim? Not according to many of the scientists in these pages. The Danish climatologist Bo Christiansen examined nine Mann “hockey sticks” and says it is “almost impossible to conclude” from any of them that “the present period is warmer than any period in the reconstructed period”. Professor David Legates writes that “one can have no confidence in the claim that the 1990s are the warmest decade of the last two millennia” (by then Mann had extended his flexi-shaft back another millennium.) Almost every other serious reconstruction shows much greater natural climate variability, and the 1990s within the bounds of that. And, as Professors McShane and Wyner point out, most of these reconstructions look nothing like hockey sticks. Indeed, it remains an open question whether what his oeuvre purports to divine a “global temperature” is in a scientific sense “supportable”. In the absence of reliable tropical data, says Dr David Rind, “we have no way of knowing how cold (or warm) the globe actually got”. So unsupported claims: yes.
2) Hidden biases Later in this book, Nobel Prize winner Ivar Giaever reminds us that “in pseudoscience you begin with a hypothesis which is very appealing to you, and then you only look for things which confirm the hypothesis”. Mann began with a hypothesis that the global temperature record had been pretty stable for 900 years and then in the 20th century it soared up and out the roof. And so he looked for “things which confirm the hypothesis”: As Mann put it, “one set of tree-ring records” was “of critical importance” in conjuring his stick .So his hypothesis that it looks like a hockey stick is confirmed only because a tree ring that produces a hockey-stick shape is given 390 times the weight of a tree ring that does not. That tells you nothing about what the temperature was in the 15th century, but a lot about Mann’s biases. He chose a statistical method that, as the US National Research Council noted rather primly, “tends to bias the shape of the reconstructions”. Furthermore, the scientists who actually collected the tree-ring data that Mann cannibalized insist they’re primarily an indicator of CO 2 fertilization, not temperature. At the IPCC level, he maintained his bias against anything that contradicted his hypothesis. As Professor John Christy testified to Congress, Mann “misrepresented the temperature record of the past thousand years by (a) promoting his own result as the best estimate, (b) neglecting studies that contradicted his, and (c) amputating another’s result so as to eliminate conflicting data”. Hidden biases: yes.
3) Lack of reproducibility Is Mann’s work “reproducible”? They gave it a go in Berlin. “She came to the conclusion that she cannot reproduce his diagram,” says Professor Ulrich Cubasch. “The real problem in this case, in my view, is that Michael Mann does not disclose his data.” Except for a small trusted coterie, Mann declined for years to release the elements needed to reproduce his stick. In evidence before the House of Commons in London, Professor Darrel Ince noted Mann’s refusal to cough up his computer code, and said that he would “regard any papers based on the software as null and void”. His stick could be neither proved nor disproved and, as Professor Vincent Courtillot reminded European climatologists, if “it’s not falsifiable, it’s not science”. Lack of reproducibility: yup. So three strikes, he’s out. No, wait, that’s another sport entirely.
For hockey, you need four.
4) Inadequate peer review “The hockey stick is an extraordinary claim which requires extraordinary evidence,” wrote Oxford physicist Jonathan Jones. Nature never asked for any and, when it fell to others to demonstrate the flaws of the stick, the journal declined to share their findings with its readers. Mann and a few close allies controlled the fora that mattered, and banished any dissidents. “It’s a completely rigged peer-review system,” concluded CalTech’s Dr David Rutledge. Fourth strike. The unsupported claims, hidden biases, lack of reproducibility and inadequate peer review of Mann have surely harmed “public trust in science”. What follows is one scientist and his science, by those who know both the work and the man.