There’s actually relatively little ice on land. (Primarily Antarctica and Greenland) enough to raise sea levels by a couple of feet but certainly not the hundreds the alarmists like to predict.
There’s roughly 33 million cubic kilometes of ice on the polar ice caps, most of it in Antarctica. The world’s oceans cover 361 million square kilometers. If all the ice on the polar caps melted it would increase sea level by something like 361/33 = 0.09 kilometers ~ 300 feet, to one significant figure.
The polar ice caps are not going to completely melt, regardless of what you read in the Washington Post. There is plenty of potential for disaster, but most serious oceanographers admit that there is only potential, actual evidence of imminent disaster is lacking. (And who, really, would count it as a disaster if Washington, Boston, ... okay, don’t go there.)