Eleven thousand years ago, the world's temperatures suddenly rose drastically, creating a climate shift within a human lifetime that is nearly unimaginable. Miles deep, the frigid expanse holds 70 percent of the world's fresh water in a deep freeze cold enough to shatter steel. Recently things have been heating up. In 1995, an iceberg the size of Rhode Island broke off from the Larsen ice shelf along the Antarctic coast, hinting at a potential meltdown....