The alternative is to prove Mark Twain right when he said: “Whiskey is for drinking; water is for fighting over.”

The key to managing water better is to price it properly, giving consumers a reason not to waste it and investors an incentive to build infrastructure to supply it.

. But a lot of the problem stems from lousy water management, and that is something the officials who meet in dusty Marrakesh this week for the next round of annual UN climate talks should ponder.

Suppose in the future there is a movement to ban the color yellow. Proposals to paint anything yellow are denounced as "yellowist", as is anyone suspected of liking the color. People who like orange are tolerated but viewed with suspicion. Suppose you realize there is nothing wrong with yellow. If you go around saying this, you'll be denounced as a yellowist too, and you'll find yourself having a lot of arguments with anti-yellowists. If your aim in life is to rehabilitate the color yellow, that may be what you want. But if you're mostly interested in other questions, being labelled as a yellowist will just be a distraction. Argue with idiots, and you become an idiot.