Featured Science Paper
Observations beneath Pine Island Glacier in West Antarctica and implications for its retreat
Thinning ice in West Antarctica is currently contributing a substantial and increasing volume to global sea-level rise, and scientists have identified Pine Island Glacier (PIG), in the Amundsen Sea, as a major source. As part of a series of investigations to better understand the impact of melting ice on sea level, an exciting new discovery has been made. Using Autosub (an autonomous underwater vehicle) to dive deep and travel far beneath the PIG’s floating ice shelf, scientists working on the research vessel Nathaniel B. Palmer made ocean and sea-floor measurements revealing a submarine ridge rising 300m above the surrounding sea floor.
Pine Island Glacier was once scraping across this underwater ridge, which slowed its flow. However, in recent decades it has thinned and disconnected from the ridge, allowing the glacier to move ice more rapidly from the land into the sea. This also permitted relatively warm seawater to flow over the ridge and into a widening inner cavity, more than doubling the ice shelf area exposed to the corrosive ocean. As the melting increases the glacier accelerates, drawing down the inland ice and moving its vulnerable grounding line (where the ice begins to float) deeper into the interior of the West Antarctic Ice Sheet.
Jenkins, A., Dutrieux, P., Jacobs, S.S., McPhail, S.D., Perrett, J.R., Webb, A.T., White, D. 2010
Nature Geoscience, 3, No.7, 468-472