The world in which we live is a small garden of well-explored territory surrounded by a dim and dark forest of disasters. Disasters lurking in the distance are legion: asteroids and comets; world-wide pandemics and plagues; nuclear and non-nuclear wars; droughts, famines, and floods; volcanic eruptions, earthquakes, and tsunamis; human over-population and extinction of non-humans; rising temperatures and sea-levels; falling temperatures and spreading ice ages; exhaustion of clean air and water; disappearance of forests, farms, and fish.