I doubt outside of gamma ray bursts if anything can actually wipe out all humanity. And even then, a nuclear bunker on the Earth is far more habitable than any non settlement.

In fact, I'll argue that any money spent on vanity Mars settlements is going to save more lives in a calamity if it is spent helping developing countries lift people out of poverty.

> although I have to think it should be easy enough to see how doing a trial run making mars habitable might translate into ways to save the Earth from becoming inhabitable.

That is hilarious. It is far easier to save the earth than make Mars habitable. It is far easier to study self sustainable pods on Earth than a settlement on Mars.

Atleast be frank why you are interested in a Mars settlement, it has nothing to do with saving humanity.

Meteor or comet strike can easily wipe us all out just as it did Dinosaurs. And new science is suggesting impacts such as the one that killed off dinosaurs are more frequent than previously thought. So a big one (not necessarily as big as to completely end life on Earth but with potential to kills hundreds of millions if not billions of people and/or at the very least end our civilisation and set us back hundreds of years) could be happening every couple of tens of thousands of years instead of hundreds of millions of years as previously thought.

And smaller impacts that might not completely wipe us off but could cause millions of casualties are possibly even more frequent. Something like Tunguska meteor can potentially kill millions of people if it hits a big metropolis given our current population density. If it hits Tokyo or New York instead of middle of nowhere in Siberia, it would be devastating.

I am not seeing what you mean to say. Will starting a costly Mars settlement dependent on Earth for resources prevent these asteroids? Isn't a self sufficient pod on Earth/space/moon much easier starting point? Isn't a nuclear bunker under the Earth as safe from these calamities as a settlement on Mars itself?

Finally, I don't think a meteor which wiped out dinosaurs will wipe out humans. We can always use a nuclear bunker and save a few hundred humans with years of food to survive on.

Moon has no atmosphere so there is very little protection against cosmic impacts. For Earth, at least, small meteorites burn when falling through upper atmosphere. I am not sure about Mars' atmosphere and how much it protects against impacts.

Just because I outline reasons why people might want to have a Mars terraforming project or similar does not mean that I am interested in a Mars settlement.