1491: New Revelations of the Americas Before Columbus

by Charles C. Mann

Housing perhaps seventy thousand souls, Wari was a dense, alley-packed craze of walled-off temples, hidden courtyards, royal tombs, and apartments up to six stories tall. Most of the buildings were sheathed in white plaster, making the city sparkle in the mountain sun. In 1000 A.D., at the time of our imaginary overflight, both societies were reeling from a succession of terrible droughts. Perhaps eighty years earlier, dust storms had engulfed the high plains, blackening the glaciers in the peaks above. (Ice samples, dug out in the 1990s, suggest the assault.) Then came a run of punishing dry spells, many more than a decade in duration, interrupted by gigantic floods. (Sediment and tree-ring records depict the sequence.) The disaster’s cause is still in dispute, but some climatologists believe that the Pacific is subject to “mega-Niño events,” murderously strong versions of the well-known El Niño patterns that play havoc with American weather today. Mega-Niños occurred every few centuries between 200 and 1600 A.D. In 1925 and 1926, a strong El Niño—not a mega-Niño, but one that was bigger than usual—blasted Amazonia with so much dry heat that sudden fires killed hundreds, perhaps thousands, of people in the forest. Rivers dried up, their bottoms carpeted with dead fish. A mega-Niño in the eleventh century may well have caused the droughts of those years.