Overview
- Researchers from the University of Victoria and GEOMAR report model results in AGU Advances showing a potential Southern Ocean heat release under negative emissions scenarios.
- The mechanism involves deep convection triggered as surface waters densify during sustained cooling, bringing warm deep water upward and venting heat to the air.
- The simulations indicate a multidecadal to centennial temperature increase of several tenths of a degree, with stronger impacts projected for the Southern Hemisphere.
- Heat can escape quickly while most dissolved carbon remains in the ocean, complicating the assumed tight link between cumulative CO2 and near‑term global temperature.
- Given that the Southern Ocean has absorbed about 50% of excess ocean heat since 2005 and roughly 40% of anthropogenic CO2, the authors urge testing across other climate models and caution that carbon budgets and negative‑emissions plans may need reevaluation.