MWP and LIA in Yukon Territory: Peer Reviewed Paper

CO2 Science report on a paper in Quaternary Research 77: 355-367.

Bunbury, J. and Gajewski, K. 2012. Temperatures of the past 2000 years inferred from lake sediments, southwest Yukon Territory, Canada. Quaternary Research 77: 355-367. 


Lake sediments from four sites in the southwest Yukon Territory, Canada, provided paleotemperature records for the past 2000 yr. An alpine and a forest site from the southeastern portion of the study area, near Kluane Lake, and another alpine-forest pair of lakes from the Donjek River area located to the northwest yielded chironomid records that were used to provide quantitative estimates of mean July air temperature. Prior to AD 800, the southwest Yukon was relatively cool whereas after AD 800 temperatures were more variable, with warmer conditions between ~ AD 1100 and 1400, cooler conditions during the Little Ice Age (~ AD 1400 to 1850), and warming thereafter. These records compare well with other paleoclimate evidence from the region.

What was learned
The two researchers state that their chironomid-inferred temperature estimates from the two lakes "compare well with one another and also with other paleoclimate evidence from the region," noting that their data suggest "relatively warm conditions during medieval times, centered on AD 1200, followed by a cool Little Ice Age, and warming temperatures over the past 100 years." More specifically, we estimate from the graphical representations of their data that the Medieval Warm Period at both lake sites extended from about AD 1100 to 1350. And we estimate that the most recent (AD 1990) of their temperature determinations were about 0.8°C cooler than the peak warmth of the Medieval Warm Period at Jenny Lake and approximately 0.5°C cooler at Upper Fly Lake.

What it means
These results now join the many other similar results, from all around the world, which we have archived in the databases of our Medieval Warm Period Project, where it can be seen that the Medieval Warm Period was not only a global phenomenon, but that its peak warmth was very likely greater than that of the Current Warm Period: see here and here.