History, repeating itself

Bill Marsh has an article in The New York Times about drought in America:

Long before the current drought or the continuing conversation about  global warming, before the Dust Bowl, the climate in large portions of the American West was far drier than modern humans have become accustomed to. The nineteenth and twentieth centuries, ancient tree rings show, were a relative oasis of settlement-friendly weather. The most reliable annual climate records go back just eighty years. For the longer view, scientists studied sections of more than two hundred ponderosa pine and Douglas fir trees, some living, some dead, some almost a thousand years old. Reading the tree rings, researchers stitched together a historical record of rainfall in El Malpais National Monument in New Mexico. (The researchers extracted pencil-thin wood cores from the living trees so as not to kill them.)
Widely spaced rings indicate wetter seasons; narrower rings indicate parched years. The resulting two-millenniums-plus record, from 137B.C. to 1992, is graphed here. Individual droughts, like those in this young century, may be severe, but the bigger picture, from El Malpais, suggests that the West has endured far drier periods.
Uncomfortably drier.

Rico says people won't like it when the cycle gets even drier...