An East Coast blizzard howling, global temperatures peaking, the desert Southwest flooding, drought-stricken California drying up—surely there’s a common thread tying together this “extreme” weather. There is. But it has little to do with what recent headlines have been saying about the hottest year ever. It is called business as usual. Surface temperatures are indeed increasing slightly: They’ve been going up, in fits and starts, for more than 150 years, or since a miserably cold and pestilential period known as the Little Ice Age. Before carbon dioxide from economic activity could have warmed us up, temperatures rose three-quarters of a degree Fahrenheit between 1910 and World War II. They then cooled down a bit, only to warm again from the mid-1970s to the late ’90s, about the same amount as earlier in the century.