CORRECTION TO: A 2000-YEAR GLOBAL TEMPERATURE
RECONSTRUCTION BASED ON NON-TREE RING PROXIES

"A climatic reconstruction published in E&E (Loehle, 2007) is here corrected for various errors and data issues....
Standard errors and 95% confidence intervals are added.
...
In addition, the present note treats the 18 series on a more uniform basis than in the original study. Data in each series have different degrees of temporal coverage. For example, the pollen-based reconstruction of Viau et al. (2006) has data at 100-year intervals, which is now assumed to represent 100 year intervals (rather than points, as in Loehle, 2007). Other sites had data at irregular intervals. This data is now
interpolated to put all data on the same annual basis. In Loehle (2007), interpolation was not done, but some of the data had already been interpolated before they were obtained, making the data coverage inconsistent.
...
The corrected data continue to show the Medieval Warm Period (MWP) and Little Ice Age (LIA) quite clearly. The confidence intervals in Figure 2 indicate that the
MWP was significantly warmer than the bimillennial average during most of approximately 820 – 1040 AD, at the 5% level (2-tailed). Likewise, the LIA was significantly cooler than the bimillennial average during most of approximately 1440-1740 AD.
....
While instrumental data are not strictly comparable, the rise in 29 year-smoothed global data from NASA GISS (http://data.giss.nasa.gov/gistemp) from 1935 to 1992 (with data from 1978 to 2006) is 0.34 Deg C. Even adding this rise to the 1935 reconstructed value, the MWP peak remains 0.07 Deg C above the end of the 20th Century values, though the difference is not significant."

[same reference given above]

So, rather than .3 C higher; as far as can accurately measured with this data and in this manner, the Medieval Warm Period was about same global temperature as end of 20th Century. And one should keep in mind that one can't assume this is accurate in such timescales as years or even period as short as a decade.

Craig Loehle acknowledges:
"Eric Swanson, Gavin Schmidt, Steve McIntyre and the visitors to Climate Audit (climateaudit.org) who helped uncover errors in data handling."