OS13A-2012
Increased Climate Variability in the Southern Ocean During the Late Twentieth Century
Monday, 14 December 2015
Poster Hall (Moscone South)
Zoe Thomas1, Chris SM Turney1, Christopher Joseph Fogwill2, Jonathan Gray Palmer1, Erik van Sebille3, Matt McGlone4, Sarah Richardson4, Janet Wilmshurst4,5, Pavla Fenwick6, Violette Zunz7, Hugues Goosse8, Kerry-Jayne Wilson9, Lionel Carter10, Mathew Lipson1, Richard T Jones11, Melanie Harsch12, Graeme Clark1, Ezequiel Marzinelli1,13, Tracey Rogers1, Eleanor Rainsley14, Laura Ciasto15, Stephanie Waterman16 and Australasian Antarctic Expedition 2013-2014 Members, (1)University of New South Wales, Sydney, Australia, (2)University of New South Wales, Sydney, NSW, Australia, (3)Imperial College London, Grantham Institute, London, United Kingdom, (4)Landcare Research, Hamilton, New Zealand, (5)University of Auckland, Auckland, New Zealand, (6)Gondwana Tree-Ring Laboratory, Canterbury, New Zealand, (7)UCL, Louvain-La-Neuve, Belgium, (8)Université Catholique de Louvain, Louvain-La-Neuve, Belgium, (9)West Coast Penguin Trust, Charleston, New Zealand, (10)Victoria University of Wellington, Antarctic Research Centre, Wellington, New Zealand, (11)University of Exeter, Exeter, United Kingdom, (12)University of Washington Seattle Campus, Seattle, WA, United States, (13)Sydney Institute of Marine Science, Mosman, Australia, (14)University of Wollongong, Wollongong, Australia, (15)Geophysical Institute, Bergen, Norway, (16)University of New South Wales, Climate Change Research Centre & ARC Centre of Excellence for Climate System Science, Sydney, Australia
Abstract:
The Southern Ocean plays a fundamental role in the global ocean-climate system. Increasing temperatures in the Antarctic Circumpolar Current have been observed over recent decades, but as a result of sparse historical sampling, the onset of warming and mechanism(s) remain uncertain. Here we integrate ocean and atmospheric observations with climate-sensitive tree growth on subantarctic islands to produce a unique temperature record across 4˚ of latitude in the southwest Pacific. We demonstrate a dramatic increase in climate variability across the second half of the Twentieth Century that is unprecedented over the last 140 years (coincident with an order of magnitude decline in the populations of many marine species). Reanalysis and climate modelling suggests this increased variability is a result of increasing westerly wind strength and Southern Ocean warming. Projected increases in westerly wind strength are likely to continue to have significant impacts on biota.
