Rapid climatic changes during the Greenland stadial 1 (Younger Dryas) to early Holocene transition on the Norwegian Barents Sea coast

• Published in: Boreas Vol. 31; no. 3; pp. 215 - 225
• Main Authors: Seppä, Heikki, Birks, Hilary H., Birks, H. J. B.
• Format: Journal Article
• Language: English
• Published: 01.09.2002
• Subjects: PNE, Barents Sea; Fennoscandia; ANE, Norwegian Sea; ASW, North Atlantic
• ISSN: 0300-9483
• DOI: 10.1080/030094802760260337

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. 6.0 degree C) and dry conditions probably resembling modern arctic deserts. The increase in July mean temperatures to the Holocene level (10.0-12.0 degree C) took place in a two-step pattern interrupted by a short cool period with July mean temperatures of c. 8.0 degree C during the early Preboreal at c. 11450-11200 cal. yr BP. The reconstruction also suggests two other early-Holocene coolings of c. 1.5 degree C dating to 10900-10800 cal. yr BP and 10400-10200 cal. yr BP, synchronously with short-term decreases in delta super(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.