Michael Mann is one of the most partisan advocates for the catastrophic anthropogenic global warming theory. He is controversial for several reasons: he invented the “hockey stick” graph, which was intended to show that recent warming trends were unprecedented, and has since been exposed as a hoax that misrepresents historic temperatures. He has fought bitterly to prevent his own emails from being discovered in litigation, even though he is a public employee whose research is lavishly funded by taxpayers. He has participated in some of the dishonest “tricks”–their word–by which climate alarmists have kept billions of dollars in government money flowing their way.

Along with his other faults, Mann is litigious. He has sued National Review, the Competitive Enterprise Institute and Mark Steyn for criticizing him, a case he inevitably will lose.

It is generally believed in the scientific community, I think, that Michael Mann is a fraud and a liar, as well as a bully. To understand why, check out Steve McIntyre’s post at Climate Audit on Mann’s effort, along with others in the alarmist community, to bury the post-1960 tree ring data that contradicted Mann’s hockey stick.

Over the years, climate scientists have used tree rings–i.e., the width of tree rings in certain locations and in certain years–to reconstruct historic climates. Reliance on tree ring data is controversial, for obvious reasons: can we really determine temperatures 1,000 years ago by measuring rings in a particular tree, or group of trees, in a random location? Many are skeptical, but alarmists needed tree ring data to negate the overwhelming evidence of temperature variation in the past, e.g., the Medieval Warm Period. The problem was that the same tree ring data that the alarmists needed to smooth out past ups and downs in the Earth’s climate showed cooling, not warming, after 1960.

John Christy was a Lead Author of the Third Intergovernmental Panel on Climate Change, whose report was published in 2001. In Congressional testimony, he explained how a politically-motivated desire to promote the hockey stick caused Michael Mann and others to falsify data:

The Hockey Stick curve depicts a slightly meandering Northern Hemisphere cooling trend from 1000 A.D. through 1900, which then suddenly swings upward in the last 80 years to temperatures warmer than any of the millennium when smoothed. To many, this appeared to be a “smoking gun” of temperature change proving that the 20th century warming was unprecedented and therefore likely to be the result of human emissions of greenhouse gases. … We were appointed L.A.s in 1998. The Hockey Stick was prominently featured during IPCC meetings from 1999 onward. I can assure the committee that those not familiar with issues regarding reconstructions of this type (and even many who should have been) were truly enamored by its depiction of temperature and sincerely wanted to believe it was truth. Skepticism was virtually non-existent. Indeed it was described as a “clear favourite” for the overall Policy Makers Summary (Folland, 0938031546.txt). In our Sept. 1999 meeting (Arusha, Tanzania) we were shown a plot containing more temperature curves than just the Hockey Stick including one from K. Briffa that diverged significantly from the others, showing a sharp cooling trend after 1960. It raised the obvious problem that if tree rings were not detecting the modern warming trend, they might also have missed comparable warming episodes in the past. In other words, absence of the Medieval warming in the Hockey Stick graph might simply mean tree ring proxies are unreliable, not that the climate really was relatively cooler. The Briffa curve created disappointment for those who wanted “a nice tidy story” (Briffa 0938031546.txt). The L.A. [Michael Mann] remarked in emails that he did not want to cast “doubt on our ability to understand factors that influence these estimates” and thus, “undermine faith in paleoestimates” which would provide “fodder” to “skeptics” (Mann 0938018124.txt). One may interpret this to imply that being open and honest about uncertainties was not the purpose of this IPCC section. Between this email (22 Sep 1999) and the next draft sent out (Nov 1999, Fig. 2.25 Expert Review) two things happened: (a) the email referring to a “trick” to “hide the decline” for the preparation of report by the World Meteorological Organization was sent (Jones 0942777075.txt, “trick” is apparently referring to a splicing technique used by the L.A. [Michael Mann] in which non-paleo data were merged to massage away a cooling dip at the last decades of the original Hockey Stick) and (b) the cooling portion of Briffa’s curve had been truncated for the IPCC report (it is unclear as to who performed the truncation.) … When we met in February 2000 in Auckland NZ, the one disagreeable curve, as noted, was not the same anymore because it had been modified and truncated around 1960.

In other words, Michael Mann and his co-conspirators simply deleted the data that didn’t fit their theory, without disclosing that they had done so.

In the graphic below, the figure on the left is a blow-up of the far-right portion of the dramatic hockey stick diagram as it was featured in the IPCC’s Third Assessment Report. It purports to show steeply rising temperatures in the latter portion of the 20th century. The green line represents Keith Briffa’s tree ring data. Note how it discreetly disappears behind the other lines. The graphic on the right shows Briffa’s data as it actually existed. The later decades of Briffa’s data, showing a sharp decline in temperature after 1960, were simply cut out in the diagram as published by the IPCC:

As discussed in the Climategate emails, this is how Mann and his fellow alarmists “hi[d] the decline” in Briffa’s data. It is hard to imagine a worse case of scientific fraud, but the history of alarmist “climate science” is rife with this kind of misconduct. In my opinion, the systematic alteration of data by government agencies to make the past look cooler is just as bad. This is what happens when governments offer billions of dollars to scientists, but only if they come up with ever more alarming predictions of what will happen if we don’t give the political class more money and power.