Read here. Is Mann just unlucky or incredibly incompetent? As his science research continues to be dissected by impartial, non-Mannian professionals, it becomes abundantly clear that the latter is closer to the truth than the former.
"In one case, when interpolating the climate model data onto a different grid, the data were rotated around the Earth 180 degrees, so that model data that should be located on the Greenwich Meridian were erroneously placed at 180 degrees longitude; in another case the data in the Western Hemisphere were spatially smoothed, while the data in the Eastern Hemisphere were not.....the implications are rather interesting, since Smerdon's findings imply that Mann's stress-testing must have been too weak to actually demonstrate what they purported to do. Fascinating stuff."