Snowfall in coastal West Antarctica much greater than previously assumed

A new Antarctic accumulation distribution, based on regional model output calibrated with 1900 in‐situ observations, is used to re‐assess accumulation in 24 Antarctic ice drainage basins. When compared to the previous compilation, good agreement is found for 19 of the 24 basins, representing 93% of the ice sheet that is reasonably well covered with observations. In contrast, the Amundsen Sea sector of West Antarctica and the western Antarctic Peninsula, both data sparse regions, are found to receive 80–96% more accumulation than previously assumed. For the Pine Island and Thwaites Glaciers (West Antarctica), which have recently undergone rapid acceleration and thinning, this means a downward adjustment of their contribution to global sea level rise from 0.24 to 0.14 mm per year. Model time series do not show a significant change in Antarctic accumulation over the period 1980–2004.