[katana]

It's possible that (like hydrocarbons) there is an unknown quantity of subsurface ice on our planet which is imperceptibly rising to the surface over time but I would still maintain that whatever quantity of water we see and can measure (liquid, solid, and vapor) has remained roughly the same over time (certainly over the geologic blink of the eye that ten thousand years represents) but that the proportions among the three states it can assume have been in constant flux.

Supposedly there's evidence that at one time the entire surface of the earth was covered in a kilometer thick ice sheet (super ice age about 750 million years ago, see web page: http://millennium-debate.org/ind10ap035.htm). As far as I understand, besides temperature (at least partly a function of what the sun is up to) the only other variable affecting sea levels would be the amount of volcanic and tectonic upthrust (and decline) which the seafloor and land masses have undergone.

[Havoc]

Subsurface Ice? You mean like subsurface where all the magma rotates around and bubbles up.. Or are we mixing our theories? Water at the subsurface level would be under great pressure which would tend to have it hot, not cold.

I would argue that we've likely lost water rather than gaining it. But, I also would argue against plate techtonics. It isn't a given, it isn't observeable nor do the physics seem to work. But that's another story. cubic miles of ice and water don't just get out of the way and hide in places that can't support them or don't make sense. Ice doesn't stay ice in warm climate just because a mountain top seems like a reasonable place for a mile of extra ice to hide. That isn't the way it works. 70 percent of the earth is covered by water. Remove the volume down to the tributaries extending toward the ocean floor then tell me where you can hide that volume of water without it being problematic. I can; but, can you.