What event in O'Connell's life caused him to enter a cycle of alternate hopefulness and despair?

O'Connell describes the way in which having children changed his outlook on the world. While he recognizes the negative trends pointing toward humanity's doom, he also feels compelled to feel hopeful and to act in a hopeful manner. Otherwise, he is admitting to having brought a child into a doomed world where he would have no real chance at a future.