All the melting going on the Arctic has some researchers wondering what the world's coastlines would look like if, say, all of Greenland's ice were to melt, or all of Antarctica's. No expert ...

But you probably don’t wonder how we know the elevation of the land. In many parts of the world a quick glance at Google Maps can tell you how many feet above sea level you are at any given time.

The National Oceanic and Atmospheric Administration (NOAA) has created an interactive map showing how the country's coastline could change under various sea level ... it were to all melt ...

He said the most vulnerable ice sheets were those in the Antarctic that are marine-based—that is, the bottom of the ice sheet sits on land that is below sea level ... If all the world's ice ...