What fraction of dry land is below sea level?
This question is intriguing. At the current rate of sea rise (about 3 mm per year), all of the Earth's dry land below sea level would be submerged in just a decade. There are an estimated 49 countries around the global with at least some real estate below -0- metres elevation, but the sum of all the potential volume (around 7,500 km^3) is insignificant compared to the volume of water generated by glacial and ice cap melt:  "A meter of sea level rise is a volume 50 times greater than all of the depressions that are below sea level in the world", according to this link: http://mountainmystery.com/2015/08/17/hiding-rising-seas-in-sunken-deserts/.