Master Betty wrote:

Accurate records of temperature over a sufficient number of sample
points on the planet do not go back very far at all. Further back you
have accurate temps from a few scattered points on the planet going
back perhaps 150 years, and prior to that you have only approximate
information. The ice and trees do not provide the detail to judge the
temperature at particular times to tenths of a degree F, more like
+/- 10.0 F.

Of course you're right. Errors are possible. When you put the whole
picture together, ice samples and tree rings, can verify hypothesis,
might be a better way to put it.

But....when you look at the "records" they have no other option but
to be accurate. I mean....how can you fake a tree rings from ancient
forests? Same for properly analyzed ice samples. Human error? Of
course.

Oh, it's easy. Tree rings are not discrete lines on a board but rather fuzz
from one to the other. Where one draws the line is important. Further, tree
rings are conditioned by a number of factors other than temperatu
rainfall, absolute temperature, length of the growing season, etc. Third,
the trees were selected to have their rings measured by those with a vested
interest, Fourth, the rings were actually measured by those with that same
vested interest.

The gold standard for experimental verification of a hypothesis is a
double-blind study. Not done here. If I were collecting the data, I'd get
tree cores from 100 different trees in one acre, take pictures of the cores,
and give the pictures to a bunch of graduate students in a completely
different discipline (say, cello or elementary education) to measure, then
take an average of all the measurements.