[A-OS13] Exploring Variability and Changes in Ocean Biogeochemical Cycles

[AOS13-12] Asymmetries in the Southern Ocean and northern ocean contributions to global heat and carbon uptake

*Richard G Williams¹, Andrew J.S. Meijers², Vassil Roussenov¹, Anna Katavouta³, Paulo Ceppi⁴, Jonathan Rosser², Pietro Salvi⁵ (1.Department of Earth, Ocean & Ecological Sciences, University of Liverpool, Liverpool, UK, 2.British Antarctic Survey, Polar Oceans, Cambridge, UK, 3.National Oceanography Centre, Liverpool, UK, 4.Department of Physics, Imperial College London, London, UK, 5.Institute for Atmospheric and Climate Science, ETH Zurich, Zurich, Switzerland.)

Keywords:Ocean heat uptake, Ocean anthropogenic carbon uptake, Aerosols, Future projections, Southern Ocean, Historical climate model experiments

The Southern Ocean provides dominant contributions to global ocean heat and carbon uptake, which is widely interpreted as being a consequence of its unique upwelling and circulation. Here we show that there is an asymmetry in these contributions over the historical period in state-of-the-art climate models: the Southern Ocean providing a much larger contribution towards global ocean heat uptake than global ocean carbon uptake. We explore the reasons for this asymmetry in heat and carbon uptake by diagnosing single radiative forcing experiments over the historical period revealing that there can be suppressed heat uptake over the northern oceans. In future projections, such as SSP2-4.5, the Southern Ocean contributions to global heat and carbon uptake reach similar proportions. Hence, the past is not a reliable indicator of the future with the northern oceans becoming important for heat uptake, while the Southern Ocean becomes of comparable important for heat and carbon.