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A spatial description of climatic changes along circumpolar regions is presented based on larch tree-ring width (TRW) index, latewood density (MXD), δ13C, δ18O of whole wood and cellulose chronologies from eastern Taimyr (TAY) and north-eastern Yakutia (YAK), Russia, for the period 1900–2006, in comparison with a δ13C cellulose chronology from Finland (FIN) and a δ18O ice core record from Greenland (GISP2). Correlation analysis showed a strong positive relationships between TRW, MXD, stable isotope chronologies and June, July air temperatures for TAY and YAK, while the precipitation signal was reflected differently in tree-ring parameters and stable isotope data for the studied sites. Negative correlations were found between July, August precipitation from TAY and stable isotopes and MXD, while May, July precipitations are reflected in MXD and stable isotopes for the YAK. No significant relationships were found between TRW and precipitation for TAY and YAK. The areas of significant correlations between July gridded temperatures and TRW, MXD and stable isotopes show widespread dimension from east to west for YAK and from north to south for TAY. The climate signal is stronger expressed in whole wood than in cellulose for both Siberian regions. The comparison analysis between δ13C cellulose chronologies from FIN and TAY revealed a similar declining trend over recent decades, which could be explained by the physiological effect of the increasing atmospheric CO2. TRW, MXD and δ13C chronologies from TAY and YAK show a negative correlation with North Atlantic Oscillation index, while the δ18O chronologies show positive correlations, confirming recent warming trend at high latitudes. The strong correlation between GISP2 and δ18O of cellulose from YAK chronologies reflects the large-scale climatic signal connected by atmospheric circulation patterns expressed by precipitation. [ABSTRACT FROM AUTHOR]

A brief review is presented of the progress, to date, in constructing a long, continuous ring-width chronology from living and subfossil Siberian larch (Larix gmelinii) in the eastern part of the Taimyr peninsula. A near 2500-year chronology running up to the present has been assembled and several shorter, earlier series have been produced that are dated approximately on the basis of radiocarbon dates. A description is given of the production of separate early summer and annual mean temperature histories based on the recent chronology, spanning more than 2000 years. These two reconstructions are based on alternative methods of statistical processing of the measured tree-ring data. The early summer and annual reconstructions agree well in the long-term components of their variability, providing evidence for anomalous warmth in the third, tenth to twelfth, and twentieth centuries, and a prolonged cool period throughout the sixteenth and seventeenth, and in the early nineteenth centuries. The mean growth and other statistical parameters of the earlier chronologies also suggest that conditions for tree growth were very favourable in the earlier Holocene, particularly in the fourth millennium BC. This is strongly indicative of an early Holocene Climatic Optimum in Taimyr at that time. Other material in hand, and earlier published radiocarbon dates, demonstrate the feasibility of constructing continuous ring-width chronologies and temperature estimates extending throughout all of the last 8000 years. [ABSTRACT FROM AUTHOR]