entire Arctic Ocean during the coldest phases of the Ice Ages. A new study, now published in Science Advances , questions this idea. The research team found no evidence of such a permanent, pan-Arctic ice [...] ice shelf. Instead, the Arctic Ocean appears to have been covered by seasonal sea ice, allowing open water—and life—to persist even during the harshest glacial periods of the past 750,000 years. This discovery [...] discovery sheds new light on how the Arctic has responded to climate extremes in the past—and how it may evolve in the future.