Secular Trends in High Northern Latitude Temperature Reconstructions Based on Tree-Rings

Boreal tree-ring records from high latitude North America, Scandinavia and Russia provide baseline data reflecting long-term trends in Arctic annual temperature. Reconstructions from 1682-1968 indicate the latter part and termination of the Little Ice Age and that the northern regions are now warmer by comparison. The resulting high-resolution, extended temperature time series allows examination of underlying causes of climatic change not possible using only the instrumental record. The recent recorded data for the Arctic show recovery from the cooling in the 1950's-1960's. The overall evaluation confirms that the high northern latitudes are now in an anomalously warm state relative to the past three centuries.