It's not actually a far-seeing perspective though. Right now, the rate at which we can get human beings off-world is outstripped by several orders of magnitude by the birthrate. I don't see that changing much even in a fantastic sci-fi future. Planetary colonisation is not a solution to overpopulation for this reason. At best, we'll get a tiny population of human beings on a new planet (the genetics of which will be fascinating. I expect that they will be almost entirely white, like old science fiction was, unless India and China overtake Europe and the US. Actually, that's pretty likely), which, if successfully nurtured, will grow and develop until we have two overpopulated planets.
But how about escaping from environmental change? Anywhere we find to live will have to be Earth-like, and I know all about terraforming. I know that even the best terraformed planet will be unlike Earth in peculiar ways (gravity, solar radiation, magnetic field protection etc) and will take so much more time to accomplish than we can expect to have before the arrival of an impending disaster. I should think, though, that if we can make another planet Earth-like, then we would be able to make the Earth Earth-like too. However, deliberately altering the Earth's climate on that scale, even to fix it, well... that's an experiment we would be really dumb to try. Exactly as dumb as fucking up the Earth in the first place.
We can ruin the Earth one way or another and flee to a new one. That is what decades of science fiction has taught us to hope for. I say that this is dumb. We should hope for something much better. In this scenario, we are not escaping from the problem, we are bringing it with us. People! Those fuckers! We are exactly the kind of species that can ruin its home, bring a privileged few into space to find a new one, painstakingly construct a new home from scratch, and learn absolutely nothing from the experience. Whatever problem we are running from, we can expect to create anew at our destination.
No. Colonise the galaxy if you can, sure, I'm all down with that. But I see no scenario where humanity survives at all in which the Earth has not also survived.
I think it is time, in more ways than one, that we move away from the narratives of our future that we told ourselves in the last century. They aren't healthy, they aren't likely. Most of the promises we made for science and technology did not come true and in the world our parents have forged for us, they probably won't. We have so many problems right here that won't go away simply by assuming that they one day will. Our ideas for the future skip over that fight. Optimism is entirely unjustified. I really mean that. There is not a single solution to any of the problems facing humanity that can be successfully implemented without three crucial elements: non-corrupt government, accountable leadership, and a general approval for the performance of civic duty, and we need all of these globally.
We will die here on this rock without them. What are our odds? The Earth will be both our cradle and our grave without a serious rethink, and science and technology by themselves are not enough. It's not enough to have solutions, you have to be able to employ them and be willing to pay the cost of doing so. We are spoiled, petulant, and privileged. I suspect that we will collectively refuse to do anything of the sort.
Try listening to all these while you play your videogames. Also, argue with the voices in your head all day long. They are clever, but they're also full of shit.