When water in the ocean evaporates, what happens to the salinity of the ocean?
The salinity increases, as it has been for that last several billion years. The ocean is always loosing water through evaporation, but fresh water (with a small amount of dissolved salt) is always flowing back in. As this process continues, the amount of water in the ocean barely changes, but the amount of salt is continuously increasing. This process will continue, until the amount of salt that is trapped in sediments equals the amount introduced from the “fresh” water sources. The ocean has not yet reached that point, and may not for another billion years. And as you may note, this change takes a LONG time.
