Scientists have estimated how much the sea level would rise, but the exact amount of land lost would require a very complicated worldwide coastal survey.
Perhaps only the military knows.
Melting the East Antarctic Ice Sheet would raise sea levels about 60 meters worldwide, or about 200 feet, while melting the West Antarctic Ice Sheet would raise the level about 6 meters, or just under 20 feet.
Greenland would also make a contribution, though its ice is viewed as being more stable than either of the halves of Antarctica.
The official estimates for the effect of a Greenland melt off are between 7.1 meters and 7.4 meters, something less than 24 feet.
The potential total would thus be approximately 244 feet.
If the ice at the North role melted, it would not affect sea levels much at all, because it is frozen sea water itself, a giant ice cube of ocean that occupies just a few meters on the top.
The concern is fresh water ice, which comes from precipitation on the continents; if it melted, it could create a pulse of fresh water into the ocean.
A wild guess of acreage lost would be based on figuring out how much of the ever-changing coastline, with an estimated slope of one foot in a thousand, would be below the new sea level.
Scientists would also have to account for continental rebound after the load from the Antarctic ice mass went away.
The weight has kept the continent below sea level, and if the load were removed, the mantle of the earth would move up to compensate.
Scandinavia is actually still rising from the ice load that left it about ten thousand years ago.
