Read here. Climategate scientists used every conceivable bogus methodology to eliminate the Medieval warming from their favored proxy records. Despite these IPCC encouraged techniques, new paleoclimate evidence continues to be presented providing the empirical evidence that the Medieval warming did occur, both in the Northern and Southern Hemispheres. (click on image to enlarge)
"The authors analyzed decadally-averaged δ18O records...they produced "a low latitude δ18O history for the last millennium" that they use as a surrogate for air temperature. For the Quelccaya Ice Cap, this work revealed that peak temperatures of the MWP were warmer than those of the last few decades of the 20th century.""....[C3 note: the dark blue curve is a 3-decade running mean]
More historical charts here. Other climate history postings here. Modern temperature charts.
