Centennial-scale trends in the Southern Annular Mode revealed by hemisphere-wide fire and hydroclimatic trends over the past 2400 years

Millennial-scale latitudinal shifts in the southern westerly winds (SWW) drive changes in Southern Ocean upwelling, leading to changes in atmospheric CO2 levels, thereby affecting the global climate and carbon cycle. Our aim here is to understand whether century-scale shifts in the SWW also drive ch...

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Published in:Geology
Main Authors: Fletcher, MS, Benson, A, Bowman, DMJS, Gadd, PS, Heijnis, H, Mariani, M, Saunders, KM, Wolfe, BB, Zawadzki, A
Format: Article in Journal/Newspaper
Language:unknown
Published: Geological Soc America 2018
Subjects:
Online Access:https://eprints.utas.edu.au/28815/
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spelling ftunivtasmania:oai:eprints.utas.edu.au:28815 2023-05-15T13:31:53+02:00 Centennial-scale trends in the Southern Annular Mode revealed by hemisphere-wide fire and hydroclimatic trends over the past 2400 years Fletcher, MS Benson, A Bowman, DMJS Gadd, PS Heijnis, H Mariani, M Saunders, KM Wolfe, BB Zawadzki, A 2018 https://eprints.utas.edu.au/28815/ unknown Geological Soc America Fletcher, MS, Benson, A, Bowman, DMJS orcid:0000-0003-2215-7685 , Gadd, PS, Heijnis, H, Mariani, M, Saunders, KM, Wolfe, BB and Zawadzki, A 2018 , 'Centennial-scale trends in the Southern Annular Mode revealed by hemisphere-wide fire and hydroclimatic trends over the past 2400 years' , Geology, vol. 46, no. 4 , pp. 363-366 , doi:10.1130/G39661.1 <http://dx.doi.org/10.1130/G39661.1>. atmospheric CO2 Southern Ocean lake sediment Tasmania Article PeerReviewed 2018 ftunivtasmania https://doi.org/10.1130/G39661.1 2021-09-20T22:17:01Z Millennial-scale latitudinal shifts in the southern westerly winds (SWW) drive changes in Southern Ocean upwelling, leading to changes in atmospheric CO2 levels, thereby affecting the global climate and carbon cycle. Our aim here is to understand whether century-scale shifts in the SWW also drive changes in atmospheric CO2 content. We report new multiproxy lake sediment data from southwest Tasmania, Australia, that show centennial-scale changes in vegetation and fire activity over the past 2400 yr. We compare our results with existing data from southern South America and reveal synchronous and in-phase centennial-scale trends in vegetation and fire activity between southwest Tasmania and southern South America over the past 2400 yr. Interannual to centennial-scale rainfall anomalies and fire activity in both these regions are significantly correlated with shifts in the SWW associated with the Southern Annular Mode (SAM; atmospheric variability of the Southern Hemisphere). Thus, we interpret the centennial-scale trends we have identified as reflecting century-scale SAM-like shifts in the SWW over the past 2400 yr. We identify covariance between our inferred century-scale shifts in the SWW and Antarctic ice core CO2 values, demonstrating that the SWW-CO2 relationship operating at a millennial scale also operates at a centennial scale through the past 2400 yr. Our results indicate a possible westerly-driven modulation of recent increases in global atmospheric CO2 content that could potentially exacerbate current greenhouse gas–related warming. Article in Journal/Newspaper Antarc* Antarctic ice core Southern Ocean University of Tasmania: UTas ePrints Antarctic Southern Ocean Geology 46 4 363 366
institution Open Polar
collection University of Tasmania: UTas ePrints
op_collection_id ftunivtasmania
language unknown
topic atmospheric CO2
Southern Ocean
lake sediment
Tasmania
spellingShingle atmospheric CO2
Southern Ocean
lake sediment
Tasmania
Fletcher, MS
Benson, A
Bowman, DMJS
Gadd, PS
Heijnis, H
Mariani, M
Saunders, KM
Wolfe, BB
Zawadzki, A
Centennial-scale trends in the Southern Annular Mode revealed by hemisphere-wide fire and hydroclimatic trends over the past 2400 years
topic_facet atmospheric CO2
Southern Ocean
lake sediment
Tasmania
description Millennial-scale latitudinal shifts in the southern westerly winds (SWW) drive changes in Southern Ocean upwelling, leading to changes in atmospheric CO2 levels, thereby affecting the global climate and carbon cycle. Our aim here is to understand whether century-scale shifts in the SWW also drive changes in atmospheric CO2 content. We report new multiproxy lake sediment data from southwest Tasmania, Australia, that show centennial-scale changes in vegetation and fire activity over the past 2400 yr. We compare our results with existing data from southern South America and reveal synchronous and in-phase centennial-scale trends in vegetation and fire activity between southwest Tasmania and southern South America over the past 2400 yr. Interannual to centennial-scale rainfall anomalies and fire activity in both these regions are significantly correlated with shifts in the SWW associated with the Southern Annular Mode (SAM; atmospheric variability of the Southern Hemisphere). Thus, we interpret the centennial-scale trends we have identified as reflecting century-scale SAM-like shifts in the SWW over the past 2400 yr. We identify covariance between our inferred century-scale shifts in the SWW and Antarctic ice core CO2 values, demonstrating that the SWW-CO2 relationship operating at a millennial scale also operates at a centennial scale through the past 2400 yr. Our results indicate a possible westerly-driven modulation of recent increases in global atmospheric CO2 content that could potentially exacerbate current greenhouse gas–related warming.
format Article in Journal/Newspaper
author Fletcher, MS
Benson, A
Bowman, DMJS
Gadd, PS
Heijnis, H
Mariani, M
Saunders, KM
Wolfe, BB
Zawadzki, A
author_facet Fletcher, MS
Benson, A
Bowman, DMJS
Gadd, PS
Heijnis, H
Mariani, M
Saunders, KM
Wolfe, BB
Zawadzki, A
author_sort Fletcher, MS
title Centennial-scale trends in the Southern Annular Mode revealed by hemisphere-wide fire and hydroclimatic trends over the past 2400 years
title_short Centennial-scale trends in the Southern Annular Mode revealed by hemisphere-wide fire and hydroclimatic trends over the past 2400 years
title_full Centennial-scale trends in the Southern Annular Mode revealed by hemisphere-wide fire and hydroclimatic trends over the past 2400 years
title_fullStr Centennial-scale trends in the Southern Annular Mode revealed by hemisphere-wide fire and hydroclimatic trends over the past 2400 years
title_full_unstemmed Centennial-scale trends in the Southern Annular Mode revealed by hemisphere-wide fire and hydroclimatic trends over the past 2400 years
title_sort centennial-scale trends in the southern annular mode revealed by hemisphere-wide fire and hydroclimatic trends over the past 2400 years
publisher Geological Soc America
publishDate 2018
url https://eprints.utas.edu.au/28815/
geographic Antarctic
Southern Ocean
geographic_facet Antarctic
Southern Ocean
genre Antarc*
Antarctic
ice core
Southern Ocean
genre_facet Antarc*
Antarctic
ice core
Southern Ocean
op_relation Fletcher, MS, Benson, A, Bowman, DMJS orcid:0000-0003-2215-7685 , Gadd, PS, Heijnis, H, Mariani, M, Saunders, KM, Wolfe, BB and Zawadzki, A 2018 , 'Centennial-scale trends in the Southern Annular Mode revealed by hemisphere-wide fire and hydroclimatic trends over the past 2400 years' , Geology, vol. 46, no. 4 , pp. 363-366 , doi:10.1130/G39661.1 <http://dx.doi.org/10.1130/G39661.1>.
op_doi https://doi.org/10.1130/G39661.1
container_title Geology
container_volume 46
container_issue 4
container_start_page 363
op_container_end_page 366
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