The “grounding line” of Thwaites Glacier in West Antarctica is, without hyperbole, one of the most important places on one of the most important objects in the natural world. And scientists now have video of it for the first time.
Earlier this week, researchers published the first images of the place where this behemoth glacier, which is both one of the world’s largest and most vulnerable, sits on the deep seafloor and bleeds water into the ocean. In other words, they have made a film of sea-level rise in progress, showing ice from the land becoming water in the ocean.
But this may understate the importance of these visuals. Thwaites is one of a handful of glaciers in the world that could really matter in our lifetime: If it collapses, it could do so rapidly, cataclysmically spiking global sea levels during the next few decades. The question of whether it will collapse depends almost entirely on its grounding line and the processes shown in this video.
One of the scientists who drove Icefin, the submersible robot that actually took the video, told me that it felt like a “walking on the moon” moment for glaciology. But it struck me as more like the first photo of a black hole, published last year—the picture’s a little dusty and shadowy, sure, but it shows something ancient, mysterious, and capable of tremendous destruction. The difference is that this shadowy place is not safely far away in space, but only 10,000 miles or so from where you’re sitting right now.