Asklemmy

C) keep the planet we have habitable

If we can't manage to keep Earth's ecosystem thriving to support us, we certainly won't be able to create a new self-sustaining ecosystem elsewhere. And without that, there's no chance of any non-Earth settlement being able to sustain a healthy human society and culture long-term.

Without some serious (currently impossible) terraforming, Mars colonies are limited to deep caves or heavily shielded buildings, no outside to relax, nowhere else to go. Have a look at the list of crimes in Antarctica, a similar situation where people are stuck together, that's not a good environment for mental health, and it will be worse farther away. A Mars colony (edit: or space station) owned by a private company will be a corporate prison, the inhabitants are 100% dependent on that company - who would voluntarily put their lives into the hands of the whims of some narcissistic hoarder with no empathy or regard for workers?

Launch Billionaires into deep space without supplies

Men will do anything other than go to therapy.

D) Move manufacturing and other dirty processes off planet and live here.

Yes.

Seriously, we should be doing both as long term space habitats can serve as a way to reduce the cost of moving cargo around.

If we can do B, A doesn't provide many benefits.

A 1km diameter, 30km cylinder would provide enough area to feed ~140k people. 95km^2 of space.

That is assuming no imported food etc, based on 7000m^2 per person which is almost 2 acres each.

140k people is a small city.

We should be exploring both options, exploration can often lead to unexpected discoveries and technological advancement.

Why not both?

I'm guessing B will happen first, just because we have so much more control of the environment, but we're still so far away from either one... Maybe I'll get to see the early stages sometime in my life.

Why? Nice planet we've got here, we could focus on preventing it becoming inhabitable due to climate change instead.

Space colonies. That way they can be dropped to earth to start colony independence wars.

How about we focus our efforts on unshittifying Earth first, eh?

Porque no los dos?

All of the above. But start with cleaning up this planet. Build better / more sustainable and more diverse communities and energy production. Build arcologies in the arctic, deserts, oceans. Those are good “practice” for building the same off planet.

Fix our own planet first

A quote attributed to a few people, Heinlein and Pournelle for two, "If you can get your ship into orbit, you're halfway to anywhere." Both space and planets have shared and their separate problems to solve. In my head I prefer the image of most populations moving into habitats in space, customized to their preferences, with smaller settlements on various bodies for their own purposes. In my realistic view I don't see us getting that far before we get bogged down with all the problems we've created on this planet. The window to a permanent space civilization might have already shut. A sad thing, as a 70s kid I grew up convinced we were full speed into some version of what scifi had sold to me.

Ringworld.

Actually, both.

After reading A City on Mars by Kelly and Zach Weinersmith I think a O'Neill Cylinder spinning spaceship for artificial gravity type is more achievable than planarity colonisation.

But the main point of the book, and I am fairly convinced of the more I think about it, is that it is a lot of effort and risk for not a lot of gain and we are entirely unprepared for space colonisation.

Neither. There's plenty of room and resources here on Earth. I think it's fine to do space exploration and even have research bases on moons and other planets, but I just don't see the imperative for colonization.

Both.

Genetically modify ourselves so that we can live both in zero gravity (and maybe survive short exposure to vacuum) and on other planets.

How to survive in space: Develop ways to survive in space only first. Once you manage that all the other problems are trivial compared and you don't have a single point of failure (aka our planet) anymore. Isn't that obvious?

I don’t think space habitats any significant distance from Earth will be possible. Mitigating the increased radiation will be tough enough just trying to get to Mars, much less trying to stay in space out that far. At least on Mars we can hang out in old lava tubes or something.

If we are capable of doing one, then we can do both.

Both! All three!