Crevasses near the grounding line of Pine Island Glacier in Antarctica. (Ian Joughin/University of Washington) Antarctica’s ice sheet is melting at a rapidly increasing rate, now pouring more than 200 billion tons of ice into the ocean annually and raising sea levels a half-millimeter every year, a team of 80 scientists reported Wednesday. The melt rate has tripled in the past decade, the study concluded. If the acceleration continues, some of scientists’ worst fears about rising oceans could be realized, leaving low-lying cities and communities with less time to prepare than they had hoped. The result also reinforces that nations have a short window — perhaps no more than a decade — to cut greenhouse-gas emissions if they hope to avert some of the worst consequences of climate change. Antarctica, the planet’s largest ice sheet, lost 219 billion tons of ice annually from 2012 through 2017 — approximately triple […]