"You’re Not Allowed to Do This in Science"

TBear, youv;e got it wrong.
“Just to be clear about this.
Is the underlying point, by Briffa, that there has been a marginal temperature increase over the 20th Century, but the 20th Century up-trend is not off the charts, by comparison with previous centuries and, so, may well just be natural variability? As opposed to an increase that looks, when plotted, freaking scary and, hence, may be caused by the cardon dioxide monster”
The data that was erased was tree ring data. Theory says that tree rings respond somewhat linearly to temperature. So, they measure rings. Then they calibrate the rings against temperature in the instrument period. Then the “reconstruct” past temps from tree rings. From 1960 on for one region of the world Briffa found that after 1960 tree rings went in the Opposite direction from the temps in that region.
That left these choices.
1. the temp data was wrong
2. tree rings dont track temperature
3. Something happened to these trees, they diverge.
From our book.. sorry if the formating is effed up
“To get a sense of how Briffa treated the problem in the original source material, it’s instructive to review his early papers, those cited by Jones, papers all too familiar to the readers of CA. In 2006 McIntyre drew attention to Briffa’s discussion of the divergence problem and posted the following graphics from Briffa’s paper in 1998, 2000 and 2004. … tree ring width and maximum latewood density are shown to
diverge from the recorded temperature. …
So, part of Jones’ defense is correct. CRU, specifically, Briffa had displayed this divergence clearly in prior publications. And the underlying literature does discuss the problem in detail.
Briffa, 1998 writes:

During the second half of the twentieth century, the decadal-scale trends in wood
density and summer temperatures have increasingly diverged as wood density has
progressively fallen. The cause of this increasing insensitivity of wood density to
temperature changes is not known, but if it is not taken into account in
dendroclimatic reconstructions, past temperatures could be overestimated… In the areas where the growth data extend through to the warm late 1980s and early 1990s
(NEUR, WSIB, CSIB, ESIB), the divergence is at a maximum in the most recent
years. Over the hemisphere, the divergence between tree growth and mean summer
temperatures began perhaps as early as the 1930s; became clearly recognisable,
particularly in the north, after 1960; and has continued to increase up until the end
of the common record at around 1990.

It’s important to understand everything at play in Briffa’s argument because it will help illustrate why Jones’ graphic misleads readers. As Briffa and others had found, during the second half of the 20th century some tree measures had started to diverge from the temperature record. The underlying science holds that some trees are temperature sensitive. That is, their growth
properties follow temperature, amongst other things. By studying these measures over time the scientists can reconstruct past temperatures. Very simplistically, higher temperatures correlate with thick ring width for example. Temperature goes up, tree rings get wider. (We say simplistically because the width of tree rings is influenced by a lot of factors and it is not, well,
simple.) By looking at tree rings during the instrumented period and the widths seen in that period it is hoped that past temperatures can be reconstructed. The problem Briffa and others found was a divergence from this pattern. The tree ring series and the ring width series marched hand in hand from 1850 to the mid 20th century but then in some species and some locations this pattern changed. There are several ways to handle a problem like this. If tree rings and temperatures diverge, one
can question the accuracy of the temperatures, or question the tree rings, or question tree ring
science itself, or some combination of these. The precedent for questioning the temperature
record is established in the literature. As noted in previous chapters and on CA, Wilson and others
had on occasion compiled their own temperature records, specifically in Canada, when the
official record was at variance with tree rings. Briffa does not even explore this possibility with
these rings. In his mind, Jones’ instrument record is a fact. If the instrument record cannot be
questioned then Briffa is left with fewer choices. He could just use the data as it is. But if he does
this, then as he writes “past temperatures could be overestimated.” That is, if the data is merely
used “as is” then past temperatures will appear higher. It’s vital to note that he would see such an
estimation as an “over estimation.”
But to some the data is just the data. If tree rings or density reflect the temperature, then these
rings would indicate a warmer past than the present. To preserve a cooler past (which politically
he must do to show that current warming is unprecedented), Briffa must “do something” with this
data. He’s left with two choices. He could argue that these tree rings show that the basic science of reconstruction is flawed. The basic science operates on a theory that a tree that is temperature sensitive today will be temperature sensitive in the past. If that’s not true, if trees can sometimes function as “treemometers” and sometimes diverge from that, then the hopes of reconstructing past climate are dashed. Briffa cannot bring himself to even discuss this logical possibility. Briffa is left then with one choice: He cannot question Jones’ temperature record. He cannot use the data as is and create a large MWP, he cannot question the very science he carries out, so he must “adjust” the data. In his case the adjustment is a simple deletion. The data that diverges is simply disappeared. To be sure, that deletion is “discussed” but the discussion consists merely of pointing at possible reasons for the phenomena. In 2006 McIntyre canvasses the theories in the
following post:…..