Antibiotic resistance, giant mosquitos [1], mutant rats [2]. Pests are evolving to continue living despite our pesticides. We aren't going to make the Earth too hot to live on, or block out the sun with pollution. We're going to be forced off of the planet by evolved pests and predators.
Like species which were forced out of the water, onto dry land, because they were out-competed -- one of our evolutionary advantages is that we can survive in space.
We're going to be forced off of the planet by evolved pests and predators.
Doubtful. They may impact our growth or even trim back our numbers, but we're numerous and have lots of mutations too. If technology doesn't save us, it's likely that we'll experience some sort of evolution that allows us to adapt. Even back before modern medicine, the Plague only managed to wipe out 2/3 of the population.
one of our evolutionary advantages is that we can survive in space
I doubt we'll be getting many humans out into space any time before some sort of Singularity beyond which we're all just guessing anyway.
Like species which were forced out of the water, onto dry land, because they were out-competed -- one of our evolutionary advantages is that we can survive in space.
[1] http://www.gainesville.com/article/20130305/ARTICLES/1303098...
[2] http://www.thenational.ae/news/world/middle-east/iran-deploy...