The Moon will not hit the Earth. The Moon is moving away form the Earth a few centimeters a year due to tidal interactions. An impact from an asteroid is definitely possible. Pole shifts as described by Hancock are not possible. But solar activity could be an issue. The predictions of solar activity are bad. It would be reasonable to say they are not as good as the weatherman. Clearly these are complex problems that will take some time to resolve if they ever are. As you so corrected state, "We don't know enough about it."
And here is the best statement, "but we humans very well could end up destroying this planet." We are capable of poisoning and damaging large parts of out planet.

