Coherent deglacial changes in western Atlantic Ocean circulation

Hong Chin Ng*, Laura F. Robinson, Jerry F. McManus, Kais J. Mohamed, Allison W. Jacobel, Ruza F. Ivanovic, Lauren J. Gregoire, Tianyu Chen

*Corresponding author for this work

Research output: Contribution to journalArticle (Academic Journal)peer-review

39 Citations (Scopus)
322 Downloads (Pure)

Abstract

Abrupt climate changes in the past have been attributed to variations in Atlantic Meridional Overturning Circulation (AMOC) strength. However, the exact timing and magnitude of past AMOC shifts remain elusive, which continues to limit our understanding of the driving mechanisms of such climate variability. Here we show a consistent signal of the 231Pa/230Th proxy that reveals a spatially coherent picture of western Atlantic circulation changes over the last deglaciation, during abrupt millennial-scale climate transitions. At the onset of deglaciation, we observe an early slowdown of circulation in the western Atlantic from around 19 to 16.5 thousand years ago (ka), consistent with the timing of accelerated Eurasian ice melting. The subsequent weakened AMOC state persists for over a millennium (~16.5–15 ka), during which time there is substantial ice rafting from the Laurentide ice sheet. This timing indicates a role for melting ice in driving a two-step AMOC slowdown, with a positive feedback sustaining continued iceberg calving and climate change during Heinrich Stadial 1.

Original languageEnglish
Article number2947
Number of pages10
JournalNature Communications
Volume9
Issue number1
DOIs
Publication statusPublished - 27 Jul 2018

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