In fact, Thwaites Glacier is melting but not due to global warming. Western Antarctica is heated by magma upwelling from the earth below. If or when the glacier melts completely, there would be a substantial rise in mean sea level (MSL). And, yes, a short distance from the seacoasts of America there would be flooding of beachfront and waterfront properties that are less than six feet above MSL, about two blocks inland.
John N. White 