How different would the world be if the sea was fresh water?

Massively, I expect. In so many ways. In fact I doubt many species including us would have evolved to the states we're currently in. Maybe on average further advanced species, maybe less.

But I like to think about it as a fun exercise given our state in the last few thousand years. If the sea was fresh water, and still had the mixture of life in it that it has had for that period. How green would our land masses be and how well fed would humans be after we perfected irrigation? How many of us would be actually living at sea on islands and even artificial floating islands due to wars and other stupid pointless crap humans get up to? Stuff like that.




...then whoa, differences...