Sep 24, 2018

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

Neil C. Swart, Sarah T. Gille, John C. Fyfe, Nathan P. Gillett
Nature Geoscience
  • 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