glacier can begin collapsing. i would really important to note about the way -- it's different than a glacier in the world is that it's not melting like a popsicle on a sidewalk on a hot summer day. because of warmer weather. it's melting because the changes in the ocean current temperature, are just water two degrees, that warmer waters are getting underneath the ice shelf. it's getting underneath the glacier self. and the concern is that by melting from below it will destabilize a lot of the glacier. most of the glacier! and the whole thing equivalent phone to the sea, curling dumping a whole bag of ice into the water at once. and that is a catastrophe. >> right steve gutters i shelf, this cracking, and that's what's cooking about that is it's a key protector for the glacier. it's a buffer zone, if the shield, it's the thing that stands between in the water. to the extended that goes away that reduces the protection of