In a world deeply divided, there are few things that bring us together. One of those things is a need for water. That need is growing dramatically at a time when supply is draining away in places from Karachi to California. Michael Specter in The New Yorker: A Thirsty, Violent World: “There are ways to replace oil, gas, and coal, though we won’t do that unless economic necessity demands it. But there isn’t a tidy and synthetic invention to replace water.”