Present level of technology and the survival instincts are too powerful not to do something about it. The aftermath of that something is . Despite everything, indications are that planet Earth is surging to become a powerhouse, a Superworld to join the leagues of Superworlds evolving throughout the universe. Then we get to share the cookies. There are no limits.
Nothing stays the same forever.
Nobody knows how soon. To ignore this fact is to remain like an ostrich with its head buried in the sand. We have awesome rocket science, computer technology, and mind power. If the comet had arrived earlier nothing could have been done about it. It would be a costly undertaking but made doable by slicing the bill into comet shares.