There's 500M to 1 billion years left for complex multi-cellular life on earth, due to increased solar output. That's around 100000x to 200000x longer than human recorded history. So clearly, not an imminent problem any rational human needs to worry about.
Trashing the planet in a few decades for such a far away "problem" is absurd. All it does is significantly shorten the time we have here. We could decide that 500M to 1B years is enough, stay here and enjoy all the time left.
If we really want to escape our fate on earth, well we could simply take our time to slowly develop ways go to space. Assuming that it is possible for humans to reach anything beyond the solar system, which may not be the case. There are practical physical and thermodynamic considerations that may prevent us from ever colonizing much in space, even if we were to try hard. In which case, preserving earth would not just be the best thing to do, it would be the only thing we can do.
> If you want to look at it in terms of natural resources, personally I think irrational fear of nuclear power is the biggest problem facing the world. Modern reactors pose almost no risk to the biosphere compared to coal, oil and the like, nor do they contribute to global warming. More people die every year from coal-burning related illness than have ever been killed by nuclear power accidents.
No disagreement here. Though it only addresses some of the issues we face, nuclear fission is probably the only semi-viable alternative to fossil fuels.