That always bugs me. To live on Mars you’d need basically a perfect food production, recycling system and economic system to make it all happen. Why don’t we make that happen here on Earth first is before using a place a hundred million miles away as an experiment? You’re only the richest man in the planet being buddies with soon to be the most powerful man on the planet (again), so not much of an excuse except “don’t wanna”.

And that’s aside from all the demons that’d need killing.

I think the most important insight is that you can achieve the same result with far less effort if you stay on Earth.

On Mars, you’re basically building survival shelters with no trade network to rely on in a hostile downright deadly environment. In a place where we don’t even know how to get there, and how to bring all the stuff we need, and many more unknowns.

It might just be that the same effort can achieve more on Earth. And no matter how bad Earth becomes in terms of climate, toxicity, heck even if atmosphere AND oceans fully turn into dead zones, it’s still far more suitable than Mars (you mentioned two important factors), and the transport problem is nonexistent or already solved.

[Edit, emphasis: Even assuming decades of nuclear winter after WW3, it’s still far more practical to build a bunker shielded against radioactivity on Earth. On Mars, you’d had to do a similar thing.

Interestingly, this argument becomes stronger the more Earth is made uninhabitable. Because any Mars colony would heavily depend on reliable supplies from Earth for decades, if not longer. Which becomes increasingly harder / more unreliable the worse the situation on Earth becomes. At some point on the scale of how bad things can become, we cannot sustain space travel any longer.]

I hope we colonize Mars some day, but it makes zero sense as a means to escape an ecological catastrophe, since Mars is orders of magnitude worse and orders of magnitude harder.

This extremely high entry barrier might possibly seem as a good thing for people who are super rich and afraid of other humans, since it makes it practically impossible for all the poor and desperate to attempt to raid their luxury bunker. Best moat ever. But again, for the same budget you can easily get an automated army of killer machines which rivals most nations, if you simply stay on Earth.

So… you don’t need to find caves. Just bring some excavators, and some prefab-structures and bury them.

This would then let you set up some place with useful resources (light for solar power, ice for drinking and stuff.

Personally, though, I vote we send Musk to the other Sister Planet. The one that’s full-on angry-goth-girl, complete with the sulphuric acid. Don’t judge, as far as planets go, she’s freaking hot.