1. I would be excited to see all three of these in the future, if I am even alive when they come into existence. There is limited land, which is being depleted of resources. If floating cities were to become a thing, that would give the land time to regenerate. The oceans in the world are, basically, "available. I would be hesitant about what it might do to the creatures living in the ocean. However, It's not like we are not harming them now with our pollution and overfishing. Plus, floating cities could potentially be a solution for population density because of loss of land/metropolises due to rising sea levels.

2. I dunno about refrigeration gel but sounds neato. lol

3. Bioluminescent trees actually does not sound too far fetched to me. I mean, there ARE bioluminescent mushrooms. Mycelium is a big factor in the ecosystem as far as forests go. I view mycelium as the nervous system of the planet, if that makes sense. I might understand it wrong, but that is how it seems since these mycelium spans hundreds of miles in some cases between forrest and trees. If that glow in the dark compound that is in those mushrooms, or jellyfish/whatever, can be taken up into the trees, that would be really interesting and potentially eliminate the need for streetlights.

thank you for the intriguing post.