Rise in ocean level increases the surface area of the ocean, because most coastlines are not vertical cliffs.  What is the average slope of dry land between 0m and 10m above sea level?<p>Reviewing the math, I concede that I may have been off by a factor of 4.  But not 6.6!<p>The estimate for the amount of water needed to cover all land but the summit of Everest is easier, since the upper limit is an ellipsoidal shell 8848m thick.  That&#x27;s about 4.5x10^9 km^3, which is 3.4 times the current ocean volume.  Then it&#x27;s just a matter of estimating how much of that volume is already full of solid matter, and reducing the amount of water needed by the rock that is already there.