The role of the Southern Ocean in the global climate response to carbon emissions

Williams, Richard G ORCID: 0000-0002-3180-7558, Ceppi, Paulo, Roussenov, Vassil ORCID: 0000-0003-4128-9712, Katavouta, Anna and Meijers, Andrew JS
(2023) The role of the Southern Ocean in the global climate response to carbon emissions. PHILOSOPHICAL TRANSACTIONS OF THE ROYAL SOCIETY A-MATHEMATICAL PHYSICAL AND ENGINEERING SCIENCES, 381 (2249). 20220062-.

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The effect of the Southern Ocean on global climate change is assessed using Earth system model projections following an idealized 1% annual rise in atmospheric CO<sub>2</sub>. For this scenario, the Southern Ocean plays a significant role in sequestering heat and anthropogenic carbon, accounting for 40% ± 5% of heat uptake and 44% ± 2% of anthropogenic carbon uptake over the global ocean (with the Southern Ocean defined as south of 36°S). This Southern Ocean fraction of global heat uptake is however less than in historical scenarios with marked hemispheric contrasts in radiative forcing. For this idealized scenario, inter-model differences in global and Southern Ocean heat uptake are strongly affected by physical feedbacks, especially cloud feedbacks over the globe and surface albedo feedbacks from sea-ice loss in high latitudes, through the top-of-the-atmosphere energy balance. The ocean carbon response is similar in most models with carbon storage increasing from rising atmospheric CO<sub>2</sub>, but weakly decreasing from climate change with competing ventilation and biological contributions over the Southern Ocean. The Southern Ocean affects a global climate metric, the transient climate response to emissions, accounting for 28% of its thermal contribution through its physical climate feedbacks and heat uptake, and so affects inter-model differences in meeting warming targets. This article is part of a discussion meeting issue 'Heat and carbon uptake in the Southern Ocean: the state of the art and future priorities'.

Item Type: Article
Uncontrolled Keywords: heat uptake, carbon uptake, climate feedback, carbon feedback, transient climate response to carbon emissions, climate projections
Divisions: Faculty of Science and Engineering > School of Environmental Sciences
Depositing User: Symplectic Admin
Date Deposited: 18 Apr 2023 07:33
Last Modified: 31 May 2023 18:01
DOI: 10.1098/rsta.2022.0062
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