dryriver writes: Phys.org reports: A key glacier in Antarctica is breaking apart from the inside out, suggesting that the ocean is weakening ice on the edges of the continent. The Pine Island Glacier, part of the ice shelf that bounds the West Antarctic Ice Sheet, is one of two glaciers that researchers believe are most likely to undergo rapid retreat, bringing more ice from the interior of the ice sheet to the ocean, where its melting would flood coastlines around the world. A nearly 225-square-mile iceberg broke off from the glacier in 2015, but it wasn't until Ohio State University researchers were testing some new image-processing software that they noticed something strange in satellite images taken before the event. "It's generally accepted that it's no longer a question of whether the West Antarctic Ice Sheet will melt, it's a question of when," said study leader Ian Howat, associate professor of earth sciences at Ohio State. "This kind of rifting behavior provides another mechanism for rapid retreat of these glaciers, adding to the probability that we may see significant collapse of West Antarctica in our lifetimes."