Even just decent sublight space colonization would probably be enough to make human survival fairly reliable for the foreseeable future, but I don't think ANY space colonization is likely in the foreseeable future. On that count, I think we're stuck on this rock for a while (unless the singularity makes it easy) and will sooner or later screw up our rock. (war, probably)

There probably are ways we could steer into a stable human populated reasonably pleasant universe, but we're in a car filled with guns liquor and dynamite on a winding mountain road in the dark.