The assessment of past temperature variations and the magnitude and characteristics of recent warmth relative to warm periods in pre-industrial times--for example, during the Medieval Warm Period (MWP)--have critical implications for understanding and quantifying the forcing of climate in natural and anthropogenic conditions. The desire to benchmark past climate variability of the northern hemisphere has resulted in four millennial-length temperature reconstructions with annual resolution. These records, however, provide different perspectives on the above issues. For example, the temperature amplitude reconstructed by Esper et al. <2002> is about 1¿C, approximately twice that of Mann et al. <1999> and Jones et al. <1998>. Additionally, Briffa <2000> and Esper et al. <2002> display a pronounced MWP followed by a significant 200-300-year-long cooling trend associated with the Little Ice Age. Such a trend is broadly absent in Mann et al. <1999> and Jones et al. <1998>.