RE: How Long Do We Have Before A Doomsday Event?
This doomsday thinking is just an excuse to pursue an insane goal to try to colonize a planet that has nothing to do with us. As other people here have pointed out, no matter how bad Earth is screwed, it will still be a better place than Mars. If the problem is survival of our species, we should build self sustained bases on Earth (maybe underground) and good planetary defenses against asteroids. The real reason for this insane plan to colonize Mars is not our survival, it is because these people are still in the space age of the 20th century and they think a colony on Mars is very cool. And even if we decide to do it just for fun, it is reasonable to point to note that we are on the verge of an AI revolution, when machines will surpass humans in most of our abilities. Machines are perfect for the space and the hostile environments of other planets, so in 20 years will make no sense to send humans to work on colonization. It makes much more sense to send the machines, wait for them to build farms, factories, mining facilities and cities there, and then just go and chill.
You know, I actually wrote about it some days ago. That when a civilisation becomes technologically advanced enough, it would not need to do the exploring itself but have robots do it for them. I agree with this point.
But I also think that we should have some amount of human presence in other planets too. There are many things we do not have control of and if they destroy the entire Earth (despite our best efforts), there should be self sustaining colonies in other planets to keep our species going. That's what I feel anyways :)
In a few decades our science and technology will be so advanced that it will be easy, cheap and safe to send humans to space. AI will bring abundance on Earth and a lot of people may become bored, so, why not do some crazy thing like go to another planet? But to follow Elon Musk's inane dream is too early. Someone may say the clock for a catastrophe is ticking, but we can wait 50 or 100 years. It is possible, though, that a man made extinction can happen in this time (like a engineered virus), but it will still be much easier to build self sustained "colonies" on Earth than on Mars. The proponents of this plan should stop telling they are doing it for humankind, and admit it is just for fun. And, as I said, there is the problem of the second generation on Mars. We have no right to force people to live in a place that looks like hell. I do not see people discussing that.