Alex Robel

In these conditions, and if the freshwater flow from melting ice is not too fast, seawater should be able to invade at least hundreds of feet past the grounding line, and probably miles, says Alexander Robel, head of the Ice and Climate Group at Georgia Tech and lead author of the new paper, published in the journal The Cryosphere. Yet, like tidal pumping, this phenomenon also isn’t represented in current models of glacial melt in Antarctica. “This is based on the prior assumption that basically there's a hydraulic barrier at the grounding line, and seawater never gets upstream,” says Robel.

What’s already obvious from the images is that, when the glacier hits the ocean, it immediately begins to change. Part of the excitement of the video is that it forces scientists to ask some basic questions, starting with “What is that?” Robel, the Georgia Institute of Technology glaciologist, told me that he expects to see many of its images in conference presentations for years to come, as scientists debate what is even happening in them.