Just as when you’re pulling nickel out of the ground in Sudbury, when you use ocean water you’re mining asteroids. As I noted in my latest essay, the more we learn about the solar system, the more we discover that, as opposed to being what we long thought was “the water planet,” earth is a comparative desert. The water is mostly extraterrestrial.
To expand on Krafft Ehricke’s famous statement, if God had wanted us to become space faring, he’d have given us a moon. With water on it.
You tamper too much with those kinds of parameters (so that, e.g., the earth has a moon which is much like [our own] earth, with water and air), then earth will likely turn out to be a waterworld with no land surface at all.
*Peers out at the vast ocean*
“It came from asteroids huh?”
“Yup.”
“Great, I feel safe now…”
“Well, only half of it.”
“That’s much better…”
Well, I suspect more comets than asteroids. They are just big, harmless, fluffy snowballs.
Well, we’ve got something like four or seven times as much water in locked in the mantle (in pyroxene and olivine) than we have in the oceans. So it might be more accurate to say that these impactors not only provided the water for the oceans, but also much of the rock the oceans rest on.