Rapid global ocean-atmosphere response to Southern Ocean freshening during the last glacial

Summary, in English

Contrasting Greenland and Antarctic temperatures during the last glacial period (115,000 to 11,650 years ago) are thought to have been driven by imbalances in the rates of formation of North Atlantic and Antarctic Deep Water (the 'bipolar seesaw'). Here we exploit a bidecadally resolved ¹⁴C data set obtained from New Zealand kauri (Agathis australis) to undertake high-precision alignment of key climate data sets spanning iceberg-rafted debris event Heinrich 3 and Greenland Interstadial (GI) 5.1 in the North Atlantic (~30,400 to 28,400 years ago). We observe no divergence between the kauri and Atlantic marine sediment ¹⁴C data sets, implying limited changes in deep water formation. However, a Southern Ocean (Atlantic-sector) iceberg rafted debris event appears to have occurred synchronously with GI-5.1 warming and decreased precipitation over the western equatorial Pacific and Atlantic. An ensemble of transient meltwater simulations shows that Antarctic-sourced salinity anomalies can generate climate changes that are propagated globally via an atmospheric Rossby wave train.

• Author: Chris S M Turney; Richard T. Jones; Steven J. Phipps; Zoë A. Thomas; Alan Hogg; A. Peter Kershaw; Christopher J. Fogwill; Jonathan Palmer; Christopher Bronk Ramsey; Florian Adolphi; Raimund Muscheler; Konrad A. Hughen; Richard A. Staff; Mark Grosvenor; Nicholas R. Golledge; Sune Olander Rasmussen; David K. Hutchinson; Simon Haberle; Andrew Lorrey; Gretel Boswijk; Alan Cooper
• Department/s: Quaternary Sciences; MERGE: ModElling the Regional and Global Earth system
• Publishing year: 2017-12-01
• Language: English
• Publication/Series: Nature Communications
• Volume: 8
• Issue: 1
• Links: http://dx.doi.org/10.1038/s41467-017-00577-6
• Document type: Journal article
• Publisher: Nature Publishing Group
• Topic: Geology; Climate Research
• Status: Published
• ISBN/ISSN/Other: ISSN: 2041-1723