Sensitivity of 21st century sea level to ocean‐induced thinning of Pine Island Glacier, Antarctica

Abstract

Pine Island Glacier (PIG), Antarctica, is rapidly losing mass, supporting arguments that it may play a major role in 21st century sea‐level rise. Yet this glacier's quantitative contribution to sea level based on theoretical and computational models is poorly known. We have developed a basin‐scale glaciological model to examine the sensitivity of PIG to a range of environmental forcings. While oceanic melt likely played the leading role in recent thinning and retreat, we find that the particular grounding‐line geometry with an extended ice plain in the 1990s made it susceptible to such forcing. Our model further indicates that while the rate of grounding‐line retreat should diminish soon, the glacier's mass loss may continue at rates similar to, or moderately elevated from, the present. While substantial, our model‐derived maximum rate of 2.7 cm/century is considerably smaller than previous heuristically‐derived bounds on the sea‐level contribution.