Yeah but colonizing Mars is just straight up cool.
>> Is it? Why?
> Well, if we get a self-sufficient mars colony up, nuking ourselves will become survivable.
Along with releasing an eco-system ravaging engineered biological organism. Or nanotechnology. Or AI. Or getting a bad luck roll with an asteroid. Or climate change blowing past a tipping point. Or something that I have no concept of anymore than an individual circa-1900 would understand the concerns of today.
Why?
Because we owe it to the !$%^ing universe to safeguard our (as near as we can tell) incredibly rare existence.
You know what happened to all those species that said "This planet is good enough?" Something bad happened. 1,000 years; 10,000 years; 100,000 years; at some point. And... poof... have fun starting another 3.5 billion year slog back to us.
Disclaimer: I don't think "us" is necessarily the pinnacle of evolution, but I tend to feel we're special enough to save another 3.5 billion years of history on recreating.
The Moon is much closer and you're facing similar problems - low gravity and virtually no atmosphere or no atmosphere. At the same time you eliminate the long trips that would complicate Mars colonization.
Also, even with the worst kind of nuclear war we can imagine, the number of people still clinging to the edge of survival on, say, New Zealand will easily surpass the biggest Martian colony we can optimistically imagine for the next 300 years.
So, if we're really that worried about our survival as a species, build a nuclear bunker in New Zealand. Actually, build one in every nation on earth. I'll bet it will be still cheaper than going to Mars.
Going to Mars is "cool", and I do want to see it in my lifetime, but treating it as some kind of insurance for mankind just doesn't make sense.
Mars has no air. That's downside.
But there's no snow to block your roads and no rain to turn them to mud. Then there's no permafrost to make ground undiggable. That's tremendous upside for e.g. mining operations.
There's no rivers, lakes or forests. There's probably some rough terrain and canyons, but you may build bridges that'll last long.
Whatever you build on Mars, stays on Mars. Whatever you build in the far north, detoriates rapidly.