The same amount of water on this planet is the same as a billion years ago, it just gets displaced, gas, liquid, solid. If the Ocean is rising in one spot , it's getting lower somewhere else, look at all the cities that are now underwater , been that way for thousands of years, Volcano's will erupt creating more land, more water displacement.
Magnetic North moves a few inches each year, the poles are moving on one side it's getting warmer and melting on the other side it's getting colder and freezing.
Millions of years ago, Michigan was covered by the ocean, we know this because of the salt mines , fossils, petosky stones are salt water fossils, then we were swamp, we know this because of the coal then the ice age came and buried Michigan under a mile or more of ice, the ice shelf melted and recided, we know this because of the great Lakes.

The water came from comets, icy comets????