I think it’s pretty naive to claim that a species that has eradicated 83% of wild animals don’t have the power to turn this globe into a dead fish tank. We have precipitated an extinction event, and if we don’t turn our focus on reducing carbon the planet will run out of breathable atmosphere as early as 2100. This is not fantasy, but science. I do agree, however, that if we are to survive we must make real efforts a colonizing off world because yes, we are all one asteroid away from joining the fossil record.

https://www.eurekalert.org/pub_releases/2015-12/uol-gwd120115.php