Also, note that one plot goes to 1980 (the end-point of Stahle data) while the other goes to 2007 (end of available temp and rain data).

Re: #38

Why do the temperature time-histories in your two graphs appear to be so different?

This one looks at Stahle and Texas temperature during May thru August. The mild negative correlation of growth with temperature is evident.

The second is Texas temperature and rainfall in May thru August, which may help explain the first time series. My conjecture is that wet years (lots of rain) are also (relatively) cool years (more clouds, rain-cooled landscape) in this region of North America and that tree growth is moisture-limited, not temperature-limited.

The r-squared for Stahle vs global temperature is 0.007

r-squared for this = -0.09

The analysis of this posting shows that PCs are not representative of different climate fields (if such things exist) but of the geographic distribution of the proxies. Mann’s conjecture of being able to detect climate fields with PCA is thus incorrect.

As a “layman” myself, and thus not one who understands the issues in the way you asked for, that’s about what I get out of Steve’s amazing analysis. Except that Mann’s conjecture still could be correct – but would have to be astronomically lucky to be so, even as a mere correlation – especially since Mann appears to have not offered any proof whatsoever that his conjecture is correct, but has apparently relied only upon begging the question, which is about all I’ve seen the ipcc AGW “science” do so far, anyway.