National Review Unkind to Global Warming Maven Mann

Anthony Watts writes for the blog Wattsupwiththat.com, a leading alternative site to the malignant global warming mass hysteria (or religion/cult if one prefers).  Watts’ piece carried the original title:  “National Review gives Michael Mann the ****stick”  and Watts begins with: 

Not just a Hockeystick, but borrowing from official CNN language last week, this appears to be the legal equivalent of a f***stick. It is quite a read.

McIntrye, McKittrick, Christy, and Andrew Montford among others are referenced.

Excerpts: 

Critics of the hockey-stick graph have focused on what they believe to be four serious flaws in its underlying methodology.

First, they have questioned the reliability of the graph’s underlying data. Because there are no thermometer records before the middle of the 19th century, the bulk of the hockey stick is composed of so-called “proxy” data, such as ancient tree rings, sedimentary pollen levels, and oxygen isotopes frozen in polar ice caps. Dr. Mann argues that these proxy data can be interpreted to provide an accurate record of global temperatures going back more than a thousand years. Some critics disagree. They argue, for example, that tree-ring formations cannot provide an accurate measure of global historical temperature trends — in part because temperatures fluctuate unevenly in different parts of the world, and in part because the relevant tree-ring characteristics are influenced not only by temperature changes but also by variable growth factors such as sunlight, water, and soil nutrients. In the eyes of critics, any statistical model that uses such data to reconstruct centuries of historical temperature trends is fundamentally flawed and misleading.

Second, critics have argued that the hockey stick relies on flawed statistical techniques, including a skewed Principal Components Analysis (“PCA”), producing an erroneous and misleading interpretation of the underlying data. For example, according to Professor David Hand, the former President of the Royal Statistical Society in Great Britain, “The particular technique [used by Dr. Mann and his co-authors] exaggerated the size of the blade at the end of the hockey stick. Had they used an appropriate technique the size of the blade of the hockey stick would have been smaller.”

(Ed comment.  The article continues after this brief interruption:  GGR comment.  The National Review legal brief linked at the very end is a “must-read” for thoughtful, unbrainwashed or non-”Al -Gored” people that want to know more than the pablum fed them by the GW zombies.  Please feel free to link to it here liberally.  And, if you have taken the anthropogenic global warming bait hook line and sinker and feel the need to “convert” me to the GW cause, talk to the hand instead and spare yourself the trouble.  I was around for the Global Cooling fiasco of the 1970s and it’s the same power hungry homo sapien haters pushing GW as it was GC.  That’s my last word on the subject.)  (More…)

Watts continues:  If one uses a better statistical method, “[t]he change in temperature is not as great over the 20th century compared to the past as suggested by the Mann paper.” Id.

Third, critics have argued that the hockey stick is misleading because it splices together two different types of data without highlighting the change: For roughly the first nine centuries after the year 1000 A.D., the graph shows temperature levels that have been inferred solely from tree-ring samples and other “proxy” data. But from about 1900 onward, the graph relies on readings from modern instruments such as thermometers. In the words of one review conducted by a panel of independent scientists, many consider it “regrettable” that temperature reconstructions “by the IPCC and others” neglected to emphasize “the discrepancy between instrumental and tree-based proxy reconstructions of temperature during the late 20th century.” J.A. 370.

Fourth, critics have contended that the hockey stick is misleading because it omits certain tree-ring data after the year 1960 that show a decline in global temperatures, and instead relies more heavily on thermometer readings that show an increase in temperatures during that period. The omission of these data gained widespread public attention after the leak of multiple e-mails from the University of East Anglia’s Climate Research Unit (“CRU”), prompting an uproar popularly known as “Climategate.” In one particularly controversial e-mail, CRU scientist Phil Jones wrote to Dr. Mann and two other scientists: “I’ve just completed Mike’s [i.e., Dr. Mann’s] Nature trick of adding in the real temps to each series for the last 20 years (i.e. from 1981 onwards) [and] from 1961 for Keith’s to hide the decline.”

Dr. Mann himself has not denied the omission of certain proxy data after the year 1960, but has argued that the omission is legitimate: “[T]hese data should not be used to represent temperatures after 1960,” he explains, because “the density of wood exhibits an enigmatic decline in response to temperature after about 1960.”

In other words, because temperature measurements from modern instruments show that these data points are not reliable, Mann contends that it is legitimate “not to show those data during the unreliable post-1960 period.” Id.

Critics disagree, arguing that the hockey stick should have included the post-1960 proxy data to give a more full and accurate picture: since modern instruments have shown tree-ring proxies to be inaccurate after 1960, they say, this also calls into question the reliability of the proxy data from earlier years, where no thermometer readings are available to provide an independent check.

Based on these four separate criticisms, Dr. Mann and his detractors have engaged in a long-running public debate over the validity of the hockey stick and its underlying methodology. Dr. Mann and his defenders characterize the hockey stick as methodologically sound, contending that it gives an accurate picture of the dire threat global warming poses. Critics of the hockey stick characterize it as badly flawed, contending that its reliance on questionable statistical techniques and its method of data presentation render it false and misleading.

In testimony before the United States Congress, Professor John Christy summarized the critical view by stating that “evidence now indicates . . . that an IPCC Lead Author working with a small cohort of scientists, misrepresented the temperature record of the past 1000 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 and limit any serious attempt to expose the real uncertainties of these data.”

…

The tone of the debate

Given the strong differences of opinion, the tone of the hockey-stick debate has been intense and at times vituperative, with both sides indulging in caustic rhetoric. Dr. Mann himselfhas harshly condemned his critics, branding them as “climate deniers,” and denouncing them as liarsand frauds. In 2005, for example, Dr. Mann wrote an e-mail to a New York Times reporter asserting that “[t]he McIntyre and McKitrick paper is pure scientific fraud,” and that “[a]number of us are . . .very surprised that Nature is publishing it.”