Thanks again jshore for your links. I was aware of the sea surface temperature measurements, in fact they were what clinched it for me.
Re the hockey stick, what I would really like to see is a graph of tree ring width, in mm or mils or whatever, vs time, for individual old trees. Just the data, no “reconstructed temperatures”, no PCA trendlines, no mixing of the data with trees from all over the place and “normalising”, no tacking thermometer measurements on the end. And big high-resolution digital images of the core drill samples on the Internet, in non-distorted photographs (or overlapping flatbed scans) that include calibrated scale markers. As raw data as you can get. Probably won’t happen, but it would at least cut the crap about methodology somewhat.
I shall cease this highjack now. No doubt it’ll come up in GD again.