Figure above shows comparison of decadally smoothed Northern Hemisphere mean and annual temperature records for the past millennium (1000-1993), based on reconstructions of Mann et al. (Mn) (11) and CL (12). The latter record has been spliced into the 11-point smoothed instrumental record (16) in the interval in which they overlap. CL2 refers to a new splice that gives a slightly better fit than the original (12). The autocorrelation of the raw Mann et al. time series has been used to adjust (adj) the standard deviation units for the reduction in variance on decadal scales. See Causes of Climate Change Over the Past 1000 Years