HARI SREENIVASAN, PBS NEWSHOUR WEEKEND ANCHOR:

Scientists are predicting a 110-mile sheet of ice — a chunk the size of the state of Delaware — will break off Antarctica in the coming days or weeks. The cause is warming ocean waters, and the ice melt has implications for sea level rise well beyond the South Pole region.

"The National Geographic" July issue cover story is called "Antarctica is Melting, and Giant Ice Cracks are Just the Start".

Joining me now from Birmingham, Alabama, to discuss this is Robert Kunzig, the senior environmental editor for "National Geographic."

Thanks for joining us.

First of all, a chunk of ice the size of Delaware seems almost impossible to, you know, put our heads around, but that's actually a small piece when you think of the size of Antarctica.