Nathaniel B. Palmer, a 308-foot-long icebreaker operated by the National Science Foundation. I had dubbed the Florida-sized slab of ice its nickname in an article I’d written a few years earlier, and the name stuck. Nevertheless, I was unprepared for how spooky it would be to actually confront the 100-foot-tall wall of ice from the deck of a ship. Locked up here in the West Antarctic ice sheet was enough water to raise global sea levels nearly 10 feet. As I wrote in a dispatch from Antarctica on the day we encountered Thwaites, it was both terrifying and thrilling to know that our future is written in this craggy, luminous continent of ice.