Synopsis: In 2002, an immense, 200-meter-thick ice shelf the size of Manhattan collapsed into the ocean off the Antarctic Peninsula, shocking scientists and raising the alarming possibility that we may be heading toward an ice-free Antarctica, last seen a million years ago. That would raise world sea levels so high that New York City would be flooded up to the level of the Statue of Liberty's shoulders. But could this really happen? Is Antarctica's surprising past a reliable guide to what may happen.