May 12, 2014

Marine Ice Sheet Collapse Potentially Underway for the Thwaites Glacier Basin, West Antarctica

Ian Joughin, Benjamin E. Smith, Brooke Medley
  • States that, resting atop a deep marine basin, the West Antarctic Ice Sheet has long been considered prone to instability
  • Investigates the sensitivity of Thwaites Glacier to ocean melt and whether unstable retreat is already underway, using a numerical model 
  • The model reproduces observed losses when forced with ocean melt comparable to estimates
  • Finds that simulated losses are moderate (<0.25 mm per year sea level) over the 21st Century, but generally increase thereafter
  • Finds that, except possibly for the lowest-melt scenario, the simulations indicate early-stage collapse has begun
  • States that the timescale is less certain, with onset of rapid (> 1 mm per year of sea-level rise) collapse for the different simulations within the range of two to nine centuries