This argument is based on the work of Don Easterbrook who relies on temperatures at the top of the Greenland ice sheet as
a proxy for global temperatures.
Using SW US drought as
a proxy for global temperature, we therefore must conclude that it is already warmer than at any time during the MWP.
C: Datasets suggesting a drying environment at 2.5 Ma, shown by λ 18O from benthic foraminifera,
a proxy for global temperature, smoothed with a Gaussian window of 200 ky; eustatic sea level; and magnetic susceptibility, a proxy for ice rafted debris and Northern Hemisphere glaciation.
If that is not enough, RealClimate has a remarkably in - depth review of the history of wine in Great Britain, and how reliable it is as
a proxy for global temperatures.
Also, many scientists believe that CET, being calculated from a number of widely spread locations, in combination with the geographical location of Britain, is demonstrated to be a reasonable - but by no means perfect -
proxy for global temperatures, and more notably that of the Northern Hemisphere.
# 73 Near surface anomolies were chosen as
a proxy for global temperature.
Given that Briffa used a few trees from Russia as
a proxy for global temperatures, that made up a huge portion of the «hockey stick», isn't that sort of like «calling the kettle black»?