Description
Using new tree-ring data from the Columbia Icefield area of the Canadian Rockies (~52.13°N, 117.13°W), Luckman and Wilson present a significant update to a millennial temperature reconstruction published for this region in 1997. The new update produced two composite summer (May-August) maximum temperature reconstructions, one based on Regional Curve Standardization of maximum latewood density (MXD RCS) and another based on standardized ring widths (RW STD).

Results of the MXD RCS chronology revealed warm intervals "comparable to twentieth century values" during the MWP (~ AD 950-1200). In contrast, from the authors' Figure 4, we calculate the peak warmth of the MWP in the RW STD chronology to be about 0.20°C above that of the CWP, which warmth is further supported by the inclusion of a "critical" snag sample of Larixlyallii in the RW STD composite that was located approximately 30 km north of the present range limit of this species.