While the data you reference is interesting, I still question the
ability of *anybody* to be able to measure either the global average
temperature or ppm atmospheric CO2 before current measurement capabilities
were developed to anywhere near the precision that these findings indicate.



I've spent a fair amount of time sifting through papers based on the Vostok
ice core data. Basically the original research authors showed that it was
likely the temperature increase was out of phase (preceded) the CO2 increases
by about 4000 years +/- 6000 or so. Sorting through the statistics really
impresses me with two things. Statistics are a very powerful tool when
applied to well behaved processes and statistics are very useful to both
prove and disprove processes that are not well behaved.

Most interesting was the accuracy of the CO2 measurements.
The accuracy of the CO2 measurements was about 2ppm base on the equipment
used and calibration methodology.
These accurate measurements then needed to be correlated with the actual year
of entrapment in the ice as well as calibrated to the currently understood
conditions at the time (i.e. temperature, ice formation rates, etc.). The
accuracy of the CO2 measurements are fine, the accuracy of the information
derived from those measurements is very dependent on preconceived notions and
assumptions.
Watch for the original data and results to "evolve" as more is learned about
the calibration models and parameters used.