Sep 24, 2018

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

by
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