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Reconstructing Summer Temperatures in Central Europe
Reference
Büntgen, U., Esper, J., Frank, D.C., Nicolussi, K. and Schmidhalter, M. 2005. A 1052-year tree-ring proxy for Alpine summer temperatures. Climate Dynamics 25: 141-153.

What was done
Using the regional curve standardization technique applied to ring-width measurements from both living trees and relict wood, the authors developed a 1052-year summer (June-August) temperature proxy from high-elevation Alpine environments in Switzerland and the western Austrian Alps (between 46°28' to 47°00'N and 7°49' to 11°30'E).

What was learned
The summer temperature reconstruction revealed the presence of warm conditions from the beginning of the record in AD 951 up to about AD 1350, which the authors associate with the Medieval Warm Period. Thereafter, temperatures declined and an extended cold period known as the Little Ice Age ensued, which persisted until approximately 1850 ... with one brief exception. For a few short decades in the mid- to late-1500s, there was an uncharacteristically warm episode, the temperatures of which were only exceeded at the beginning and end of the 1052-year record, i.e., during the Medieval and Current Warm Periods.

What it means
Regular readers of CO2 Science will recognize the significance we attach to documenting the existence of the Medieval Warm Period, Little Ice Age and Little Medieval Warm Period throughout the world, the reality of which periods of thermal extremes is typically denied by the world's climate alarmists. Strangely enough, however, evidence for these distinctive warm and cold periods continues to be discovered almost weekly, and at a variety of places around the globe, supporting our thesis that the Current Warm Period is more a product of planet-wide natural forces (which have been operating with regularity throughout the Holocene and beyond), than of accelerating CO2-induced global warming.

Reviewed 22 February 2006