Abstract

The northern hemisphere experienced an abrupt cold event ~ 8200 years ago (the 8.2 ka event) that was triggered by the release of meltwater into the Labrador Sea, and resulting in a weakening of the poleward oceanic heat transport. Although this event has been considered a possible analogue for future ocean circulation changes due to the projected Greenland Ice Sheet (GIS) melting, large uncertainties in the amount and rate of freshwater released during the 8.2 ka event make such a comparison difficult. In this study, we compare sea surface temperatures and oxygen isotope ratios from 28 isotope-enabled model simulations with 35 paleoproxy records to constrain the meltwater released during the 8.2 ka event. Our results suggest that a combination of 5.3 m of meltwater in sea level rise equivalent (SLR) released over a thousand years, with a short intensification over ~ 130 years (an additional 2.2 m of equivalent SLR) due to routing of the Canadian river discharge, best reproduces the proxy anomalies. Our estimate is of the same order of magnitude as projected future GIS melting rates under the high emission scenario RCP8.5.

Details

Title
Magnitude of the 8.2 ka event freshwater forcing based on stable isotope modelling and comparison to future Greenland melting
Author
Aguiar Wilton 1 ; Meissner, Katrin J 2 ; Montenegro Alvaro 3 ; Prado Luciana 4 ; Wainer Ilana 5 ; Carlson, Anders E 6 ; Mata, Mauricio M 1 

 Universidade Federal do Rio Grande–FURG, Laboratório de Estudos dos Oceanos e Clima, Instituto de Oceanografia, Rio Grande, Brazil (GRID:grid.411598.0) (ISNI:0000 0000 8540 6536) 
 University of New South Wales, Climate Change Research Center and ARC Centre of Excellence for Climate Extremes, Sydney, Australia (GRID:grid.1005.4) (ISNI:0000 0004 4902 0432) 
 The Ohio State University, Department of Geography, Columbus, USA (GRID:grid.261331.4) (ISNI:0000 0001 2285 7943) 
 Universidade de São Paulo, Instituto Oceanográfico, São Paulo, Brazil (GRID:grid.11899.38) (ISNI:0000 0004 1937 0722); Universidade de Brasília, Instituto de Geociências, Brasília, Brazil (GRID:grid.7632.0) (ISNI:0000 0001 2238 5157) 
 Universidade de São Paulo, Instituto Oceanográfico, São Paulo, Brazil (GRID:grid.11899.38) (ISNI:0000 0004 1937 0722) 
 Oregon Glaciers Institute, Corvallis, USA (GRID:grid.11899.38) 
Publication year
2021
Publication date
2021
Publisher
Nature Publishing Group
e-ISSN
20452322
Source type
Scholarly Journal
Language of publication
English
ProQuest document ID
2499223008
Copyright
© The Author(s) 2021. This work is published under http://creativecommons.org/licenses/by/4.0/ (the “License”). Notwithstanding the ProQuest Terms and Conditions, you may use this content in accordance with the terms of the License.