Brian Fagan, author of The Great Warming: Climate Change and the Rise and Fall of Civilizations, tells John J. Miller that the warming period of 800-1200 A.D. had its good and bad sides. In Europe, Fagan says, “There was more food. The growing seasons lengthened. You got people growing cereal crops in Norway . . . They were growing wine in central England.” However, “I was shocked to find that over enormous areas of the world, there were prolonged, even epochal, droughts, particularly in the American west and over much of the Pacific.”