10. A Stern reminder

In October, venerable economist and senior U.K. government adviser Sir Nicholas Stern released a major report on global warming. Its claims were explosive. On the grim side, global warming stands to shave up to 20 percent off the world's annual GDP by the end of the century. On the bright side, it will only cost 1 percent of the world's annual GDP to avoid the damage, if we act now.

That's perhaps history's largest...