Adam Manning

“Stopping a battle is much harder than starting it. Starting it only requires you to shout ‘Attack!’ but when you want to stop it, everyone is busy.”
― Terry Pratchett, Monstrous Regiment

“A nonindustrial Earth with a population of perhaps one billion people could be far more beautiful than it is now.  Tourism from space could be a major industry, and would serve as a strong incentive to enlarge existing parks, create new ones, and restore historical sights.  The tourists, coming from a nearly pollution-free environment, would be rather intolerant of Earth's dirt and noise, and that too would encourage cleaning up the remaining sources of pollutants here.  Similar forces have had a strong beneficial effect on tourist centers in Europe and the United States during the past twenty years.  The vision of an industry free, pastoral Earth, with many of its spectacular scenic areas reverting to wilderness, with bird and animal populations increasing in number, and with a relatively small, affluent human population, is far more attractive to me than the alternative of a rigidly controlled world whose people tread precariously the narrow path of a steady-state society.  If the humanization of space occurs, the vision could be made real.”
― Gerard K. O'Neill, The High Frontier: Human Colonies in Space