Collapsing ice shelves and calving of large icebergs in Greenland and Antarctica have recently become major drivers of sea level rise. The rapidity of these changes has come as a surprise, revealing major gaps in our understanding of how ice sheets respond to a changing climate. To a large extent, these gaps are due to the lack of measurements from the marine edge of glaciers - the Achilles' heel of glaciers. For over a decade, since the glaciers in Greenland began their retreat, Fiammetta Straneo and her group at Scripps Institution of Oceanography have been probing the edge of massive calving glaciers in iceberg-choked fjords in Greenland using helicopters, icebreakers, fishing vessels, and autonomous vehicles. The understanding gained through these measurements is being used in models aimed at improving sea-level rise predictions. Series: "Jeffrey B. Graham Perspectives on Ocean Science Lecture Series" [Science] [Show ID: 34572]