High-resolution analyses of an early Holocene climate event may imply decreased solar forcing as an important climate trigger

• Main Authors: Björck, Svante, Muscheler, Raimund, Kromer, Bernd, Andresen, Camilla S., Heinemeier, Jan, Johnsen, Sigfus J., Conley, Daniel, Koç, Nalan, Spurk, Marco, Veski, Siim
• Format: Article in Journal/Newspaper
• Language: English
• Published: Geological Society of America 2001
• Subjects: Holocene; sub-Milankovitch cooling event; lake sediments; marine records; ice-core proxies; tree rings; Δ14C; 10Be; 14C modeling; solar forcing; Greenland; Greenland Ice Sheet Project; ice core; Ice Sheet
• Online Access: https://doi.org/10.1130/0091-7613(2001)029<1107:HRAOAE>2.0.CO;2

Early Holocene lacustrine, tree-ring, ice-core, and marine records reveal that the Northern Hemisphere underwent a short cooling event at 10300 calendar yr B.P. (9100 14 C yr B.P.). The records were compared on a common high-resolution time scale and show that the event lasted less than 200 yr, with a cooling peak of 50 yr, and the event coincides with a distinct Holocene thermohaline disturbance recognized in the North Adantic Ocean. In spite of well-known freshwater forcings at the time of the event, the negligible difference between the modeled Δ 14 C record, based on the GISP2 (Greenland Ice Sheet Project 2) 10 Be data, and the measured values, does not allow for detectable Δ 14 C changes related to global ocean ventilation. We can, however, show that the onset of the cooling coincides with the onset of one of the largest Holocene 10 Be flux peaks. This finding may imply that the climate system is more sensitive to solar-related changes than previously thought and that such changes may be an important underlying mechanism for sub-Milankovitch climate variability.