Since 2018, a team of scientists forming the International Thwaites Glacier Collaboration, has been studying Thwaites — often dubbed the “Doomsday Glacier” — up close to better understand how and when it might collapse. Their findings, set out across a collection of studies, provide the clearest picture yet of this complex, ever-changing glacier. The outlook is “grim,” the scientists said in a report published Thursday, revealing the key conclusions of their six years of research.