Antarctic Shelf Ocean Warming and Sea Ice Melt Affected by Projected El Niño Changes
Subsurface ocean warming over the Antarctic shelf affects melt of ice shelf/sheets with implications for ice sheet stability and future sea level rise. A projected increase in El Niño variability is found to slow future mid-latitude Southern Ocean warming but its impact on Antarctic shelf ocean is unknown
We examine outputs from 31 climate models that participated in Phase 6 of the Coupled Model Intercomparison Project(CMIP6), in which oceanic temperatures and other circulation fields are available. These models are subject to historical forcings before 2014 and a high-emission scenario (SSP5-8.5) for future climate. Crucially, to demonstrate model credibility, these models simulate the observed feature of the high-latitude southern ocean temperature structure, with warmer ocean temperatures below 200m than that of the surface ocean
We show that a projected increase in El Niño variability slows sea ice reduction but accelerates Antarctic shelf ocean warming, thus hastening ice shelf/sheet melt, with profound implications for contributing to ice sheet instability and possibly accelerating the rate of future sea level rise