| Summary: | A pollen-based quantitative climate reconstruction from a lake-sediment core on the Norwegian Barents Sea coast provides insights about climatic change over the Greenland stadial 1 (GS-1) to early-Holocene transition. GS-1 was characterized by low July mean temperatures (c. 6.0degreesC) and dry conditions probably resembling modern arctic deserts. The increase in July mean temperatures to the Holocene level (10.0-12.0degreesC) took place in a two-step pattern interrupted by a short cool period with July mean temperatures of c. 8.0degreesC during the early Preboreal at c. 11450-11200 cal. yr BP. The reconstruction also suggests two other early-Holocene coolings of c. 1.5degreesC, dating to 10900-10800 cal. yr BP and 10400-10200 cal. yr BP, synchronously with short-term decreases in delta(18)O values in the Greenland ice cores. These results reflect the highly unstable nature of the early-Holocene climate in northernmost Fennoscandia. Apart from the cooling at 10900-10800 cal. yr BP, the reconstructed cold events correlate with fluxes of fresh water to the North Atlantic and related reductions of North Atlantic deep-water formation, suggesting that the rapid climate changes resulted from the dynamics of the North Atlantic thermohaline circulation and oceanic energy transport during the GS-1 to early-Holocene transition.
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