Meltwater Pulse 1A from Antarctica as a Trigger of the Bølling-Allerød Warm Interval

• Main Authors: Andrew J, Jerry X. Mitrovica
• Other Authors: The Pennsylvania State University CiteSeerX Archives
• Format: Text
• Language: English
• Subjects: Antarctic; The Antarctic; Antarc*; Antarctica; Fennoscandian; Ice Sheet; NADW; North Atlantic Deep Water; North Atlantic
• Online Access: http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.571.6995; http://www.cccma.ec.gc.ca/papers/osaenko/PDF/mwp1a.pdf

Meltwater pulse 1A (mwp-1A) was a prominent feature of the last deglaciation, which led to a sea-level rise of 20 meters in less than 500 years. Concurrent with mwp-1A was the onset of the Bølling-Allerød interstadial event (14,600 years before the present), which marked the termination of the last glacial period. Previous studies have been unable to reconcile a warm Northern Hemi-sphere with mwp-1A originating from the Laurentide or Fennoscandian ice sheets. With the use of a climate model of intermediate complexity, we dem-onstrate that with mwp-1A originating from the Antarctic Ice Sheet, consistent with recent sea-level fingerprinting inferences, the strength of North Atlantic Deep Water (NADW) formation increases, thereby warming the North Atlantic region and providing an explanation for the onset of the Bølling-Allerød warm interval. The established mode of active NADW formation is then able to respond to subsequent freshwater forcing from the Laurentide and Fennoscan-dian ice sheets, setting the stage for the Younger Dryas cold period. The melting of continental ice sheets during the