Punctuated Shutdown of Atlantic Meridional Overturning Circulation during Greenland Stadial 1 ...

• Main Authors: Hogg, Alan, Southon, John, Turney, Chris, Palmer, Jonathan, Ramsey, Christopher B., Fenwick, Pavla, Boswijk, Gretel, Friedrich, Michael, Helle, Gerhard, Hughen, Konrad, Jones, Richard, Kromer, Bernd, Noronha, Alexandra, Reynard, Linda, Staff, Richard, Wacker, Lukas
• Format: Article in Journal/Newspaper
• Language: English
• Published: ETH Zurich 2016
• Subjects: Palaeoclimate; Palaeoceanography; Greenland; North Atlantic; Southern Ocean
• Online Access: https://dx.doi.org/10.3929/ethz-b-000121987; http://hdl.handle.net/20.500.11850/121987

The Greenland Stadial 1 (GS-1; ~12.9 to 11.65 kyr cal BP) was a period of North Atlantic cooling, thought to have been initiated by North America fresh water runoff that caused a sustained reduction of North Atlantic Meridional Overturning Circulation (AMOC), resulting in an antiphase temperature response between the hemispheres (the ‘bipolar seesaw’). Here we exploit sub-fossil New Zealand kauri trees to report the first securely dated, decadally-resolved atmospheric radiocarbon (14C) record spanning GS-1. By precisely aligning Southern and Northern Hemisphere tree-ring 14C records with marine 14C sequences we document two relatively short periods of AMOC collapse during the stadial, at ~12,920-12,640 cal BP and 12,050-11,900 cal BP. In addition, our data show that the interhemispheric atmospheric 14C offset was close to zero prior to GS-1, before reaching ‘near-modern’ values at ~12,660 cal BP, consistent with synchronous recovery of overturning in both hemispheres and increased Southern Ocean ventilation. ... : Scientific Reports, 6 ...