The Medieval Warm Period in Greenland Vinther, B.M., Jones,
P.D., Briffa, K.R., Clausen, H.B., Andersen, K.K., Dahl-Jensen,
D. and Johnsen, S.J. 2010. Climatic signals in multiple highly
resolved stable isotope records from Greenland. Quaternary
Science Reviews 29: 522-538. Working with 20 ice core records
from 14 different sites, all of which stretched at least 200
years back in time, as well as near-surface air temperature data
from 13 locations along the southern and western coasts of
Greenland that covered approximately the same time interval
(1784-2005), plus a similar temperature data set from northwest
Iceland (said by the authors to be employed "in order to have
some data indicative of climate east of the Greenland ice
sheet"), Vinther et al. proceeded to demonstrate that winter
δ18O was "the best proxy for Greenland temperatures." Then,
based on that determination and working with three longer ice
core δ18O records (DYE-3, Crete and GRIP), they developed a
temperature history that extended more than