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In this study, we compare observed Southern Ocean temperature and salinity changes with the historical simulations from 13 models the Coupled Model Intercomparison Project version 5 (CMIP5), using an optimal fingerprinting framework. We show that there is an unequivocal greenhouse gas-forced warming in the Southern Ocean. This warming is strongest in the Sub-Antarctic Mode Waters, but is also detectable in denser watermasses which has not been shown in previous studies. We also find greenhouse gas-forced salinity changes, most notably a freshening of Antarctic Intermediate Waters. Our analysis also shows that non-greenhouse gas anthropogenic forcings - anthropogenic aerosols and stratospheric ozone depletion – have played an important role in mitigating the Southern Ocean’s warming. However, the detectability of these responses using optimal fingerprinting is model-dependent, and this result is therefore not as robust as for the greenhouse gas response.

Item Type:	Refereed Article
Keywords:	Southern Ocean, attribution, climate change, coupled models, model comparison
Research Division:	Earth Sciences
Research Group:	Oceanography
Research Field:	Physical oceanography
Objective Division:	Environmental Policy, Climate Change and Natural Hazards
Objective Group:	Understanding climate change
Objective Field:	Effects of climate change on Antarctic and sub-Antarctic environments (excl. social impacts)
UTAS Author:	Hobbs, WR (Dr Will Hobbs)
UTAS Author:	Bindoff, N (Professor Nathan Bindoff)
ID Code:	141607
Year Published:	2020
Deposited By:	Oceans and Cryosphere
Deposited On:	2020-11-03
Last Modified:	2021-03-23
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