Onset and termination of Heinrich Stadial 4 and the underlying climate dynamics

Ashish Sinha,Francisco W Cruz,Haiwei Zhang,Xue Jia,Xiyu Dong,Dianbing Liu,Hai Cheng,Hanying Li,Baoyun Zong,Jingyao Zhao,Jonathan Baker,R Lawrence Edwards,Yao Xu,Zhengyu Liu,Sonu Jaglan,Augusto S Auler,Anil K Gupta,Christoph Spötl,Yao Cai ,Raj K Singh ,Nicolás Misailidis Stríkis ,Xianfeng Wang,Som Dutt,Gayatri Kathayat,Wenjing Du

doi:10.1038/s43247-021-00304-6

Abstract

Heinrich Stadial 4 during the last glacial period was marked by severe cooling at northern high latitudes along with the attendant changes in Asian Monsoon (Chinese Stadial 4) and South American Monsoon (South American Stadial 4). Here we present improved constraints on timings of Heinrich/Chinese/South American Stadial 4 onset and termination at sub-centennial precision based on speleothem records. We show that their initial onsets were essentially synchronous (40.20 ± 0.08 thousand years ago) and led the Antarctic warming by ~300 years. The Heinrich/Chinese Stadial 4 termination commenced at 38.34 ± 0.07 thousand years ago following a centennial-scale reduction in the Amazon River runoff and a poleward shift of the Southern Westerly wind belt. These two precursor events may have contributed to a reduced Amazon Plume Region and an enhanced Agulhas salt/heat leakage that led to an abrupt resumption of the Atlantic Meridional Ocean Circulation eventually triggering the Heinrich/Chinese Stadial 4 termination.

Highlights

Heinrich Stadial 4 during the last glacial period was marked by severe cooling at northern high latitudes along with the attendant changes in Asian Monsoon (Chinese Stadial 4) and South American Monsoon (South American Stadial 4)
We argue that the aforementioned Southern Hemisphere (SH) changes were one of the important factors that contributed to the gradual recovery of the Atlantic Meridional Ocean Circulation (AMOC), which warrants further testing by model simulations
The temporal constraints of CS4/SAS4 datasets presented here are characterized mostly by sub-centennial age precision, which together with a correlation strategy based on breakpoints, provides an improved chronological and interpretive framework to explain the dynamics of global ocean-atmosphere teleconnections associated with the signal propagations during HS4

Summary

Introduction

Heinrich Stadial 4 during the last glacial period was marked by severe cooling at northern high latitudes along with the attendant changes in Asian Monsoon (Chinese Stadial 4) and South American Monsoon (South American Stadial 4). On the basis of precisely dated speleothem δ18O records, combined with polar icecore records, the evolution of SH or tropical Pacific temperature/ hydroclimate likely played an active role in DO variability/ Greenland climate dynamics[23], as hypothesized previously in a number of studies but were based mostly on numerical models or low-resolution data with loosely constrained chronologies[32,33,34,35,36] These developments, warrant further investigation of the phase relationship of millennial-scale events between different climate systems during the glacial period and their underlying mechanisms[23,37]. The long-term reproducibility for δ18O measurements at both laboratories is typically ~0.1‰ (1σ) (see “Methods” section)

Objectives

Methods

Results

Conclusion