"The best of reasons," Leo said. "Survival. Survival of humanity, and of millions of endangered species. A chance for humanity to work its way out of heavy weather into real sunlight and blue skies again. We had a lot of chances to take steps to save our world, and we blew them all, Jane. All of them. We were greedy and stupid and shortsighted, and we threw all our chances away. Not you personally, not me personally, not any of us personally, just our ancestors, of course. No one convenient to blame. But you, and me, and the people here, we are all the children of heavy weather, and we have to live under consequences, and we have to deal with them. And the only real way to deal with them is ugly, just unbearably ugly."