> We might get new resources. There are many wars happening that are all about resources. Also, we might get space, which could reduce tensions on earth.
The problem is that we grow exponentially. How long would a 2nd earth last us at our current rate or expansion and resource consumption? Not to mention the massive amount of resources we'll have to take from earth in order to reach Mars and make in inhabitable.
> What could we possibly do to Mars, that in practical terms could make it worse? It's uninhabitable already. If it matters so much to you, then I ask you if the same applies to some planet a billion light years away from us.
It's uninhabitable for us alright, but it's not like we already knew everything about Mars. The whole point of my argument (and the reason NASA is careful about not contaminating marsian soil) is because we don't know what we could find.
And no, it wouldn't matter to me if mars was a billion light years away from us. If we could easily reach new and unexplored planets I wouldn't be objecting to messing with Mars (after all, there are billions of other specimen for us to study), but that's obviously not realistic in the short term (for a big value of "short").
> Or we could also work with what we can reach. I mean it's obviously bad, that Dodos are extinct now, but was life better a thousand years ago, when we were unable to reach and work with oil and gas, even though Dodos still existed?
I'm not sure what's the argument, do you think the colonization of Mauritius and the extinction of the dodo made humanity progress significantly?
As in all things, there's a middle ground to be found, we don't need to destroy in order to move forward.