I would share his concern over the long term sustainability of the ever growing billions of humans on the planet and the inevitable depletion of ever scarcer resources, climate change etc, or even a collision with a decent sized Near Eartth Object. Looked at from a universal perspective, humanity could be viewed as clinging precariously to a single favourable niche, living on the skin of just one planet.
Technologically speaking though, I find it difficult to envisage humanity making the required substantive breakthroughs in some of the technological knowledge and application "ceilings" that we are currently facing.
Without FTL, the idea of colonising planets outside of our own solar system looks unattainable. Maybe some very sophisticated generational or colony ships, using breakthrough cloning / DNA / suspended animation technologies could work, but in all those fields we are so far away from what would be needed that I have my doubts we could conquer those challenges within 100 years.
Failing that, we could colonise within the solar system - but none of the possible targets (Mars,Moon) represent credible opportunities for either long term sustainability or mass emigration.
So - someday maybe - but not within 100 years, and we would be better served trying to figure out how to ensure that humanity is sustainable on Earth over the next century ;)