In a world where it's all water with zero land mass, could human beings still create civilizations?

I’m pretty sure they’d be adaptive to water. Evolution is inevitable for a species survival.

I wish.

Jack Vance thought so.

I highly doubt that.

Without land, we’d have adapted by evolving into fish-people eons ago, because there’d be no way to build a structure above the waterline.

There’s a lot of ifs in this scenario. If we could stop some of today’s machinery from sinking to the bottom before the giant flood, we could use things like air compressors, rubber, plastic and other tools/materials to build floating cities. The catch is that we would have to have them built, or at least started, before all the water came because we couldn’t build them from the water. Now, from there we’d have to have a way to get to the ocean floor to mine some material to continue to repair/build these cities.

Then, there’s the problem of food. Could we live off fish and seaweed our whole lives? I guess for survival we could but look at all the folk with seafood allergies. They’re pretty much screwed. We’d need some way to mine the mud from the ocean floor, dry it out and use a large space on our floating cities to lay it out and plant some food.

I see a lot of problems with the whole idea and really, as lazy and inept as most of us are these days, we’d die out like all the other land animals. I highly doubt we’d have time to evolve into fish-like creatures before we came to our doom.

No. That would be a civilization killer. Waterworld got it mostly right, mostly.

@Randy Not even floating, on pillars. The jetsons did it.

Without land, an industrial society will be very difficult to maintain. All natural resources will have to be retrieved underwater. I know we can drill for oil underwater, but what about digging for coal, which provides half our energy? What about mining for uranium? Or any other natural resource?

All of our floating platforms will probably depend mostly on resources that are difficult to get. It will be harder to get metals to make boats. But what about trees? There won’t be any. Nor any of the products we get from trees? Neither will there be any food crops. No corn, no wheat, no soy beans, no apples, no rubber, except as we can create floating platforms for. There won’t be nearly enough of those platforms to support billions of people. And where will the earth come from?

Even if we do have floating platforms, every storm will destroy some of them, and they won’t be replaceable. Maybe engineers will figure out how to use underwater biomass to create new platforms or other things we need, but that will require the development of a radical new set of technologies almost instantly.

Think about weather. With no land anywhere to stop the wind, the storms would probably go on endlessly, like the great red spot on Jupiter. The winds would howl constantly, I bet. It would be very difficult to work in those conditions. It would be hard to keep communities together.

No. I think human kind would die out pretty quickly under such a scenario. The only way “humans” could survive is if we evolved on such a planet, but then we wouldn’t be intelligent. It is doubtful we would have had opposable thumbs. So we couldn’t have wielded tools. In addition, we never would have developed industry because there would be no air to burn things. No foundries. No iron. No industry. No technology. We would be on the same level as dolphins.

Sorry. As a premise for an alternative universe it sucks, unless you assume a different physics where things can burn in water. Now that could be interesting. Think about it.

No. Life had 3.4 billion years trying to accomplish this. It didn’t happen. Fish did not turn into dolphins or australopithecines. No Eiffel tower on the ocean floor. Fish had to leave the water and find a land mass. That was about 400 million years ago.

Difficult to create fire underwater.

Impossible for exactly the reason @RocketGuy just said. We never would have learned to control fire. Without fire, even primitive medieval technology would never have happened.

Great! Underwater birthing process and there’s no other choices.