NBC: The consequences of the warming planet are being quantified in a new report from ice researchers in the Antarctic. They say the collapse of the massive West Antarctic Ice Sheet has already begun, and the melting of this ice sheet into the ocean could raise sea levels by as much as 15 feet in the coming centuries. wo teams of scientists say the long-feared collapse of the West Antarctic Ice Sheet has begun, kicking off what they say will be a centuries-long, unstoppable process that could raise...