Paleoclimate is currently used to support confidence in this science and there are important questions to answer about whether this was done correctly. It does matter.

It seems to me that with respect to tree rings in particular, there are literally dozens of variables which one would expect to have a direct impact on tree ring width and density. Even when the samples all come from remote areas at high elevations, it is incredulous to presume that all environmental factors in these regions were static for 500-2000 years.

So again, if there is little reliability and therefore little value to the science of projecting past temperatures based on seemingly conflicting proxies, why does funding continue to gush forth to those scientists, their universities and other governmental organizations dedicated to studying and defending such an unreliable and suspect line of inquiry? Please consider this a rhetorical question if it appears I’m beating a dead horse.

I’ve deleted a number of responses.

I’ll put my aberrant view. On the question of reliability and accuracy, I don’t know. But I don’t believe any fundamental policy decisions should depend on them.

The logic of AGW is: we are putting lots of CO2 in the atmosphere. This will hinder heat loss through IR radiation and lead to warming. We have observed warming which is consistent with this effect. If we keep putting CO2 in the air, and there is a lot of C available, then it will get a whole lot warmer.

It would be nice to know that the observed warming is absolutely due to CO2, so we look to the past (proxies) to see if anything similar has happened. But this should not affect policy. The fact that something else may have caused warming then (if true) does not alter the consequence of putting CO2 in the air.

A: No.

Q: Are the margins of error in these proxy studies actually may times the magnitude of the temperature variations considered to be caused by CO2 concentrations?

A: Yes.

Q: Is there reliability and scientific value in projecting past temperatures using proxy developed data, and if so, which proxies are reliable to what degree of accuracy?

A: No.

It occurs to me that whenever any of the independent proxies which are researched and promoted by various climate scientists as reliable temperature signals are compared to the actual instrument measured temperature record, there is a generally a sizable lack of correlation. In fact it seems that the proxy data must always be artificially manipulated to create even the appearance of correlation with instrument measured data (and that, despite the companion problem of whether instrument recorded temperature data was manipulated, cherry-picked regionally, or just “value added” by its gatekeepers). It also appears to me anyway, that these proxy manipulations are considered closely guarded secrets, generally omitted from overt disclosure or discussion, but instead buried in the minutia of peer reviewed articles and appendices of IPCC reports, if available at all. This lack of transparency and data manipulation seems so routine and common that I am inclined to believe that any actual convergence between proxy developed temperatures data and instrument recorded temperatures are likely mere coincidence.

My question is this: Are any of the temperature chronologies based on proxy data actually reliable enough to determine temperatures data over the past 500, 1000, 2000 years, with the degree of accuracy necessary to make fundamental policy decision concerning “climate change”? Are the margins of error in these proxy studies actually may times the magnitude of the temperature variations considered to be caused by CO2 concentrations (yes I know, an entirely different subject)?

In summary, is there reliability and scientific value in projecting past temperatures using proxy developed data, and if so, which proxies are reliable to what degree of accuracy?

Unfortunately, that means that anyone using the 1997/truncated version of the series in their data has used invalid data.