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

• Published in: Nature communications Vol. 8; no. 1; pp. 520 - 9
• Main Authors: Turney, Chris S. M., Jones, Richard T., Phipps, Steven J., Thomas, Zoë, Hogg, Alan, Kershaw, A. Peter, Fogwill, Christopher J., Palmer, Jonathan, Bronk Ramsey, Christopher, Adolphi, Florian, Muscheler, Raimund, Hughen, Konrad A., Staff, Richard A., Grosvenor, Mark, Golledge, Nicholas R., Rasmussen, Sune Olander, Hutchinson, David K., Haberle, Simon, Lorrey, Andrew, Boswijk, Gretel, Cooper, Alan
• Format: Journal Article
• Language: English
• Published: London Nature Publishing Group UK 12.09.2017; Nature Publishing Group; Nature Portfolio
• Subjects: 704/106/2738; 704/106/413; Alignment; Anomalies; Atmospheric models; Climate; Climate change; Climate models; Climate Research; Computer simulation; Datasets; Debris; Deep water; Divergence; Earth and Related Environmental Sciences; Equatorial regions; Geologi; Geology; Geovetenskap och miljövetenskap; Glacial periods; Humanities and Social Sciences; Klimatforskning; Marine sediments; Meltwater; multidisciplinary; Natural Sciences; Naturvetenskap; Planetary waves; Polar environments; Precipitation; Rainfall; Science; Science (multidisciplinary); Terrestrial environments; Wave propagation; Southern Ocean
• ISSN: 2041-1723; 2041-1723
• DOI: 10.1038/s41467-017-00577-6

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 14 C 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 14 C 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. A challenge for testing mechanisms of past climate change is the precise correlation of palaeoclimate records. Here, through climate modelling and the alignment of terrestrial, ice and marine 14 C and 10 Be records, the authors show that Southern Ocean freshwater hosing can trigger global change.