Answer:
If all the polar ice and glaciers melted, there would be a notorious rise in sea level, leaving thousands of cities located in lowlands, such as Miami or New Orleans, totally submerged under water.
Due to the melting of land ice, more water ends up in the oceans; for example, all the ice in Greenland spread across the oceans would account for seven meters of water; and a theoretical situation where all the ice in Antarctica would melt would result in an elevation of 61 meters.