I'm wondering why the melting and break-up of the sea level ice shelves indicates a "rapiid" warming of the seas. Antarctic seas are now about .6 degree C. Sea water freezes about 1.8 degrees C. depending on the salinity. If the sea temperature a few hundred years ago was near the freezing temperature of sea water, a slow and uniform warming would bring us to the current temperature. The .6 degree C. temperature is above the melting temperature of fresh water ice and the floating ice shelves are now melting and breaking up.