There are other “sleight of hand” manipulations that they seem to use whenever potentially-contradictory evidence about temperatures during the MWP is cited. For example, a standard tool in their bag of tricks is to dismiss evidence of warmer temps during the MWP at near-Arctic locations such as Greenland by claiming that they were merely “regional” occurrances but not global phenomena. However that does not prevent them from extrapolating from other near-Arctic sources, such as tree ring data from Siberia, and claiming that (notwithstanding their claims to the contrary for evidence from Greenland) such data is indeed a suitable proxy for global phenomena.
(Interestingly, the veracity of the “peer-reviewed” Siberian tree ring data and its interpretation has come under increased scrutiny that threatens to derail such arguments, and in combination with the leaked emails, is beginning to shape up as a damning indictment of the “scientists” involved in formulating that interpretation).
It reminds me of Jim and Tammy Baker where they were raising funds on their TV show for "Kevin's House".
You couldn't be a good Christian unless you gave money for "Kevin's House" for this little crippled kid named Kevin.
This is in a world where the majority of people ~ in the billions ~ have inadequate housing!.
A handful of Siberian trees then became the data source for the entire world before the modern time.
That was their proxy, much as Kevin became the proxy for all the poor people in the world.
Why am I not surprised that Dr. Mann, et al, used a TV evangelists' scam as a model?