Science Source

Recent Southern Ocean warming and freshening driven by greenhouse gas emissions and ozone depletion

States that the Southern Ocean has, on average, warmed and freshened over the past several decades, but the drivers of these changes are poorly understood
Constructs an observational synthesis to quantify the temperature and salinity changes over the Southern Ocean and combine this with an ensemble of co-sampled climate model simulations
Uses a detection and attribution analysis to show that the observed changes are inconsistent with the internal variability or the response to natural forcing alone
Finds that:
- The observed changes are primarily attributable to human-induced greenhouse gas increases, with a secondary role for stratospheric ozone depletion
- Physically, the simulated changes are primarily driven by surface fluxes of heat and freshwater