I thought this short (20 minute) video, given me by Paul Homewood of Not a Lot of People Know That, was worthy of featuring here on the blog even as it is a few years old. One, it clearly shows the chicanery Michael Mann used in constructing his famous Hockey Stick, and two, it ties in well with a private (and now one-way) conversation I was having via email.
The major players in this video are Mann, Keith Briffa, Phil Jones, Steve McIntyre, a Canadian mining engineer who would later, along with Ross McKitrick publish a paper, Hockey sticks, principal components, and spurious significance.
I have the paper in front of me. At five pages (including citations), it is both readable and digestible. McIntyre and McKitrick tested Mann’s data used in constructing the Hockey Stick, and found it lacked statistical significance. Further, they found that any data used with Mann’s methodology would produce a hockey stick, more or less a predetermined outcome. It was rigged.
Here is how it played out: Mann produced his hockey stick paper in April of 1998, called mbh98, initials being Mann’s and two other colleagues who assembled it. Unknown and not revealed, Mann had cheated by using bristlecone pine tree rings to construct the temperature line of the North American continent from 1400 forward. However, Mann switched to actual temperature measurements at the beginning of the 20th century.
He had a reason for doing this: Actual records recorded higher temperatures than did the tree rings, which actually showed a temperature decline. Shown to the left here, we can easily see that Mann records show no Minoan, Roman or Medieval Warm Periods, and no Little Ice Age. It instead shows a 900 year cooling trend that then took off in a heat wave in the 20th century. This was the intended outcome of Mann’s science. He was, in my view, obviously a hire used to engage in false science and create the illusion that we had entered a period of dangerous warming. Up until the time of Climategate, Mann’s hockey stick was a worldwide sensation.
A colleague of Mann’s at East Anglia University in Norwich, England, Keith Briffa, had done a similar study. However, Briffa’s timeline showed no spike. There was no hockey stick. This is the origin of Mann’s need to “hide the decline.” Briffa showed declining temperatures well into the 20th century using tree rings. This was at odds with Mann, who took unusual measures to hide these facts, including undermining Briffa’s work. (Fact #1: Tree rings are not necessarily a reliable proxy for historical temperatures.)
Prof Phil Jones commented on the matter in a 1999 email exposed in the Climategate scandal:
“I’ve just completed Mike’s Nature trick of adding in the real temps to each series for the last 20 years (ie from 1981 onwards) and from 1961 for Keith’s to hide the decline.”
Shown below is work from the GISP2, (Greenland Ice Sheet Project) a different proxy project that uses Greenland Ice Cores and oxygen isotopes to measure past temperatures.
“Oxygen isotopes” sounds complicated and is in actual practice, but can be understood: Certain elements have the same atomic weight but different number of neutrons. These isotopes appear in certain temperature ranges, and for that reason, GISP2 data from ice cores can tie ice cores to past temperatures.
As I understand it. Do not go by me, but rather do your own probing, as the following sentence has stifled my grasp:
The glacial δ 18 O oscillations of the GISP2 core, with their very fast onsets, are templates of a prototype oscillation of variable duration with an amplitude of 3.9‰.
From this they are able to calculate past temperatures. At a certain point I have to step off the boat and say “If you say so,” but I do have more confidence in this work than in tree rings. The latter have scientific merit, but not in the hands of Michael Mann.
We can clearly see that our current interglacial period, known as the Holocene, has had wide fluctuations in temperature. The GISP2 data was first published in 1997, a few months before Mann’s work, so that he maybe could have accessed the data. It was on the public record. But it directly conflicted with Mann’s work, and so was ignored.Mann reluctantly agreed to include Briffa’s data in the 2001 IPCC report, but truncated it. He ended it at the beginning of the 20th century, and inserted actual measured mechanical temperatures for that period. That made Briffa’s data line up with Mann’s, much to Briffa’s dismay. In the screen cap below, you can see how it affected the data.A slight downward temperature trend was upended, and replaced by a wild 20th century spike.
The red arrow points at the Briffa data in blue, with a dashed line where Mann truncated it to hide the decline. Note that Briffa’s data points at a much flatter line, showing only slight warming well into the 20th century. By the way, Briffa’s data had disappeared, and had to be recovered by Steve McIntyre, who inserted it in the above graph.
Two phrases, “hide the decline” and “Mike’s nature trick” are used in Climategate emails to describe what he did. These phrases, which are derogatory towards Mann, came from other scientists, and not from climate skeptics, or “deniers” as the propaganda defines us.
So why is this important? First, of course, Mann’s Hockey Stick is a work of fiction wherein he deliberately altered and eliminated data that did not agree with pre-ordained conclusions. That’s enough to remove him from his prestigious position at the University of Pennsylvania, but in climate science, it does not work like that. After the Climategate fiasco, the University actually whitewashed the whole ugly episode. In climate science, much like virology, the only way to fail is upward.
The obvious conclusion was that tree ring data did not pick up 20th Century warming. Therefore, it might be suspected that it missed other warm periods too, such as those uncovered by GISP2. This would throw all of mbh98 in a bad light, and cast doubt on all of its conclusions. That is how real science works – if you screw up the data, the data has to be discarded.
Instead, if we use a search engine, any one of them, to search for refutations of the Hockey Stick, they are very difficult to find. They exist, as does the McIntyre/McKitrick paper, but one has to know about them and specifically look for them. Otherwise, they remain buried. There are tons of “debunking” papers validating Mann and his work, asserting that he is still right even when proven wrong. I hate that word. “debunking,” roughly translated to mean “We own the truth, so STFU you pain-in-the-ass skeptics.”
So another branch of science found to be corrupted by political agendas. Why am I not surprised?
3 thoughts on “Hide the decline”
Mann, hockey stick, smfh.
I’ll try again.
1960’s- Oil gone in 10 years.
1970’s-Another Ice Age in 10 years.
1980’s-Acid rain will destroy all crops in 10 years.
1990’s-The Ozone layer will be gone in 10 years.
2000’s- Ice caps will be gone in 10 years.
None Happened: But all resulted in more taxes.