It’s been called the most important glacier in the world. The Thwaites glacier in Antarctica is the size of Florida, and contains enough water to raise sea levels by over half a metre. Over the past 30 years it has been melting at an increasing pace, and currently contributes 4% of annual global sea level rise. Ian Sample speaks to marine geophysicist Dr Rob Larter about a new research mission to the Thwaites glacier, the role of Boaty McBoatface and what it’s like to see a region melt away before your eyes. Help support our independent journalism at theguardian.com/sciencepod