Michael Price writes:

It was the worst time to be alive, according to some scientists. From 536 C.E. to 541 C.E., a series of volcanic eruptions in North and Central America sent tons of ash into the atmosphere, blocking sunlight, chilling the globe, and destroying crops worldwide. Societies everywhere struggled to survive. But for the Ancestral Pueblo people living in what today is the U.S. Southwest, this climate catastrophe planted the seeds for a more cohesive, technologically sophisticated society, a new study suggests.

“This story makes sense to me,” says Tim Kohler, an archaeologist at Washington State University, Pullman, who has studied climate impacts on the Pueblo people of different eras but was not involved in the new work. He says the disturbance and subsequent reorganization of the Ancestral Puebloans provide clues to what makes societies resilient in the face of dramatic climate change.

At the beginning of the sixth century, some Ancestral Puebloans—ancestors of modern Pueblo people who now live in the U.S. Southwest—grew maize, beans, and squash in small, mobile, kin-based groups across the Colorado Plateau. Other Ancestral Puebloans primarily hunted and foraged for their food, some using the bow and arrow, and others using an ancient spear-throwing technology called an atlatl.

By the turn of the next century, however, the Ancestral Puebloans had had a population boom. They were building large settlements with massive subterranean ceremonial buildings known as great kivas in Chaco Canyon in present-day northwestern New Mexico. The society had adopted large-scale farming, started to raise turkeys en masse, and began to make more durable, high-quality ceramics. Traditionally, researchers have argued this was a slow, gradual transition. But Reuven Sinensky, an anthropology graduate student at the University of California, Los Angeles, who led the new study, and his colleagues uncovered evidence of a much more rapid shift.

Over the course of his research, Sinensky had worked with contemporary Hopi farmers—descendants of the Ancestral Puebloans—and knew that they still employ a number of sophisticated traditional techniques to mitigate the impacts of bad weather, such as early frosts. His experiences led him to wonder how Ancestral Puebloan people might have handled a sudden, prolonged climate crisis. [Continue reading…]