Tree-ring data provide critical information regarding two fundamental questions as to the role of the polar regions in global change 1 what is the nature of climatic variability and 2 what is the response of vegetation to climatic variability Treering-based climatic reconstructions document the variability of the climate system on time scales of years to centuries. Dendroclimatic reconstructions indicate that the climatic episodes defined on the basis of documentary evidence in western Europe i.e., Medieval Warm Episode, ca. A.D. 1000-1300 Little Ice Age, ca. A.D. 15501850 can be observed at some high-latitude sites ex., Polar Urals. Spatial variation in long-term temperature trends ex., northern Fennoscandia vs. Polar Urals demonstrates the importance of regional-scale climatic controls. When collated into global networks, proxy-based climatic reconstructions can be used to test hypotheses as to the relative importance of external forcing vs. internal variation in governing climatic variation. Specifically, such a global network would allow the quantification of the climatic response to various permutations of factors thought to be important in governing decadal- to centennial-scale climatic variation i.e., solar insolation, volcanic activity, trace gas concentrations
This article is from 'Proceedings of the International Conference on the Role of the Polar Regions in Global Change Held in Fairbanks, Alaska on 11-15 June 1990. Volume 2', AD-A253 028, p565-569. See also Volume 1, AD-A253 027.