Last Century Warming Over the Canadian Atlantic Shelves Linked to Weak Atlantic Meridional Overturning Circulation

TitleLast Century Warming Over the Canadian Atlantic Shelves Linked to Weak Atlantic Meridional Overturning Circulation
Publication TypeJournal Article
Year of Publication2018
AuthorsThibodeau, Benoit, Not Christelle, Zhu Jiang, Schmittner Andreas, Noone David, Tabor Clay, Zhang jiaxu, and Liu Zhengyu
JournalGeophysical Research Letters
Volume45
Number22
Pages12,376 - 12,385
Date Published11/2018
Abstract / Summary

The Atlantic meridional overturning circulation (AMOC) is a key component of the global climate system. Recent studies suggested a twentieth‐century weakening of the AMOC of unprecedented amplitude (~15%) over the last millennium. Here we present a record of δ18O in benthic foraminifera from sediment cores retrieved from the Laurentian Channel and demonstrate that the δ18O trend is linked to the strength of the AMOC. In this 100‐year record, the AMOC signal decreased steadily to reach its minimum value in the late 1970s, where the weakest AMOC signal then remains constant until 2000. We also present a longer δ18O record of 1,500 years and highlight the uniqueness of the last century δ18O trend. Moreover, the Little Ice Age period is characterized by statistically heavier δ18O, suggesting a relatively weak AMOC. Implications for understanding the mechanisms driving the intensity of AMOC under global warming and high‐latitude freshwater input are discussed.

URLhttps://doi.org/10.1029/2018GL080083
DOI10.1029/2018GL080083
Journal: Geophysical Research Letters
Year of Publication: 2018
Volume: 45
Number: 22
Pages: 12,376 - 12,385
Date Published: 11/2018

The Atlantic meridional overturning circulation (AMOC) is a key component of the global climate system. Recent studies suggested a twentieth‐century weakening of the AMOC of unprecedented amplitude (~15%) over the last millennium. Here we present a record of δ18O in benthic foraminifera from sediment cores retrieved from the Laurentian Channel and demonstrate that the δ18O trend is linked to the strength of the AMOC. In this 100‐year record, the AMOC signal decreased steadily to reach its minimum value in the late 1970s, where the weakest AMOC signal then remains constant until 2000. We also present a longer δ18O record of 1,500 years and highlight the uniqueness of the last century δ18O trend. Moreover, the Little Ice Age period is characterized by statistically heavier δ18O, suggesting a relatively weak AMOC. Implications for understanding the mechanisms driving the intensity of AMOC under global warming and high‐latitude freshwater input are discussed.

DOI: 10.1029/2018GL080083
Citation:
Thibodeau, B, C Not, J Zhu, A Schmittner, D Noone, C Tabor, J Zhang, and Z Liu.  2018.  "Last Century Warming Over the Canadian Atlantic Shelves Linked to Weak Atlantic Meridional Overturning Circulation."  Geophysical Research Letters 45(22): 12376 - 12385.  https://doi.org/10.1029/2018GL080083.