[cogitator]

I think the borehole measurements give the direction and relative amplitude of the temperature variations. The actual amplitude of the variations is calibrated using the nearby surface observations. If these nearby surface observations are wrong, the borehole reconstruction will have the wrong amplitude.

OK. Comment on the following with respect to your position (i.e., do the following articles lend support or not to your arguments):

Borehole temperatures and past climates

Brief Introduction to the Geothermal Approach of Climate Reconstruction

Boreholes - Summary

Yes, It Has Warmed Over the Past Five Centuries

(And don't forget to note the source of the last two articles.)

[ancient_geezer]

(And don't forget to note the source of the last two articles.)

What does an increase in global temperature returning to interglacial norms from the little ice age:

Climate of the last 2400 years

Climate of the last 12,000 years

have to do with the IPCC storylines pushing the anthropogenic CO2 theory for warming at this time?

The point of the two articles from CO2 Science was that global increases in temperature are not caused by CO2 increase, read:

CO2-Temperature Correlations

From the same source.

Yes global temperatures have, and can change, the issue is more about whether or not a substantive or dangerous trend is currently in place and if one is, what if anything other than adaptation is the appropriate response. The evidence dose not support the conclusion of a critical or even marginally non-beneficial trend.