STEVEN GODDARD: An Entire Science Wrecked By Data Tampering.
In Briffa, 1998 – he reported that an apparent post-1960 divergence between tree ring density (thick solid line) and surface data (thin solid line) was likely due to some unknown anthropogenic effect like CO2 or acid rain. . . .
He was correct that it was a Mann-made problem, but it had nothing to do with the trees or the “ecology.” The problem was that the surface data had been altered. The temperature graph below is from the 1975 National Academy of Sciences, and shows a 0.5C drop in temperature after 1940, and a large drop from 1960 to 1965.
See the graphs at the link.