To avert catastrophe in this way would be a massive undertaking: The curtain itself would need to be up to 500 feet tall and 50 miles long. But these local conditions are in such tentative balance—“on a knife’s edge,” David Holland, a climate scientist at NYU and a member of the Seabed Curtain Project, told me from the deck of the RV Araon—that Holland and some other scientists believe that an intervention could change the glacier’s fate. Of his colleagues on the boat, he may be the only one thinking along those lines right now, he said. “But everyone’s data is going to be used by people for years and years for that purpose.”