Took 12 tree ring cores and ignoring 240 others to juice the data enough to try to hide the medieval warming period, where the Earth heated up without any modern industry. Warmists have long desired a way to hide or eliminate the tree ring data that showed there was this warm period.
Mann et al. had to make the Medieval Warm Period (about A.D. 800 to 1400) and the Little Ice Age (A.D. 1600 to 1850) statistically disappear.
The graph relied on data from trees on the Yamal Peninsula in Siberia. Here, too, the results were carefully selected. Just 12 trees from the 252 cores in the CRU's Yamal data set were used. A larger data set of 34 tree cores from the vicinity showed no dramatic recent warming, and warmer temperatures in the middle ages. They were not included.
