I’ve recently been rereading some of Arthur Clarke’s science fiction stories, so I was primed and ready for this topic. Here’s the comment I offered on the post:
Step one would be to establish orbiting stations around Venus, with artificial gravity produced in centrifuges. On these stations, we would carry out step two, the genetic engineering and then the deployment of some kind of plant that would take the form of tiny particles that would float in the clouds of Venus. Even if these plants were too small to do much individually, they could be the basis of a future ecosystem if they could temporarily link together to absorb CO2, conduct photosynthesis, and reproduce. Those linkages would be brief, broken well before their weight caused them to sink very far into the atmosphere.
Step three would be to create and deploy a series of larger creatures that would feed on these microscopic plants, and step four to create and deploy smaller creatures that would be symbiotic with the larger creatures. From there, the ecosystem of the cloud tops would begin to evolve on its own; in step five, we would supervise and direct that evolution to produce food and other useful products for future floating cities, while also sequestering as much carbon and sulfur as possible in order to expand the habitable regions of the atmosphere.
All of those preliminaries would take generations, probably centuries. And all the while, the orbiting stations would be growing in population and complexity. So by the time we got around to building habitations in the atmosphere, it would be an open question of why we would bother. You talk about surfacism; decades ago, Gerard K. O’Neill derided planetism, and predicted that “The High Frontier” of human settlement in space would be on stations with artificial gravity, not on planets where gravity is fixed at levels lethal to human life. I suspect O’Neill will turn out to have been right, and that the prime spot for stations will be inside the orbit of Mercury, where solar power is at its most abundant. But it would still be nice to turn the clouds of Venus into a huge farm of some kind.
So I envision a future in which the majority of the human race will live in a collection of huge, solar-powered cylinders clustered near to the Sun, each spinning at a rate giving it an interior surface gravity equal to that under which their ancestors evolved on Earth. Presumably the interior surface areas of this collection of cylinders will be vastly greater than that of the Earth. I’m not at all sure this is a desirable future; if the Earth isn’t enough for humanity, then it’s unlikely that anything larger than the Earth will be. Rather than the peaceful age of abundance foreseen by Clarke, O’Neill, and others, the settlement of space may well be a new age of conflict among grasping, covetous powers. But it does seem likelier than settlement of any planetary body, either on its surface or in its atmosphere.